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![Jason Wang](/assets/img/avatar_default.png)
The idx in vhost_vring_ioctl() was controlled by userspace, hence a potential exploitation of the Spectre variant 1 vulnerability. Fixing this by sanitizing idx before using it to index d->vqs. Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2435 lines
59 KiB
C
2435 lines
59 KiB
C
/* Copyright (C) 2009 Red Hat, Inc.
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* Copyright (C) 2006 Rusty Russell IBM Corporation
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*
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* Author: Michael S. Tsirkin <mst@redhat.com>
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*
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* Inspiration, some code, and most witty comments come from
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* Documentation/virtual/lguest/lguest.c, by Rusty Russell
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*
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* This work is licensed under the terms of the GNU GPL, version 2.
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*
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* Generic code for virtio server in host kernel.
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*/
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#include <linux/eventfd.h>
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#include <linux/vhost.h>
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#include <linux/uio.h>
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#include <linux/mm.h>
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#include <linux/mmu_context.h>
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#include <linux/miscdevice.h>
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#include <linux/mutex.h>
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#include <linux/poll.h>
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#include <linux/file.h>
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#include <linux/highmem.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include <linux/kthread.h>
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#include <linux/cgroup.h>
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#include <linux/module.h>
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#include <linux/sort.h>
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#include <linux/sched/mm.h>
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#include <linux/sched/signal.h>
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#include <linux/interval_tree_generic.h>
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#include <linux/nospec.h>
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#include "vhost.h"
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static ushort max_mem_regions = 64;
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module_param(max_mem_regions, ushort, 0444);
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MODULE_PARM_DESC(max_mem_regions,
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"Maximum number of memory regions in memory map. (default: 64)");
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static int max_iotlb_entries = 2048;
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module_param(max_iotlb_entries, int, 0444);
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MODULE_PARM_DESC(max_iotlb_entries,
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"Maximum number of iotlb entries. (default: 2048)");
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enum {
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VHOST_MEMORY_F_LOG = 0x1,
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};
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#define vhost_used_event(vq) ((__virtio16 __user *)&vq->avail->ring[vq->num])
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#define vhost_avail_event(vq) ((__virtio16 __user *)&vq->used->ring[vq->num])
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INTERVAL_TREE_DEFINE(struct vhost_umem_node,
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rb, __u64, __subtree_last,
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START, LAST, static inline, vhost_umem_interval_tree);
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#ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
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static void vhost_disable_cross_endian(struct vhost_virtqueue *vq)
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{
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vq->user_be = !virtio_legacy_is_little_endian();
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}
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static void vhost_enable_cross_endian_big(struct vhost_virtqueue *vq)
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{
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vq->user_be = true;
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}
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static void vhost_enable_cross_endian_little(struct vhost_virtqueue *vq)
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{
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vq->user_be = false;
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}
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static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp)
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{
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struct vhost_vring_state s;
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if (vq->private_data)
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return -EBUSY;
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if (copy_from_user(&s, argp, sizeof(s)))
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return -EFAULT;
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if (s.num != VHOST_VRING_LITTLE_ENDIAN &&
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s.num != VHOST_VRING_BIG_ENDIAN)
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return -EINVAL;
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if (s.num == VHOST_VRING_BIG_ENDIAN)
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vhost_enable_cross_endian_big(vq);
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else
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vhost_enable_cross_endian_little(vq);
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return 0;
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}
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static long vhost_get_vring_endian(struct vhost_virtqueue *vq, u32 idx,
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int __user *argp)
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{
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struct vhost_vring_state s = {
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.index = idx,
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.num = vq->user_be
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};
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if (copy_to_user(argp, &s, sizeof(s)))
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return -EFAULT;
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return 0;
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}
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static void vhost_init_is_le(struct vhost_virtqueue *vq)
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{
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/* Note for legacy virtio: user_be is initialized at reset time
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* according to the host endianness. If userspace does not set an
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* explicit endianness, the default behavior is native endian, as
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* expected by legacy virtio.
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*/
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vq->is_le = vhost_has_feature(vq, VIRTIO_F_VERSION_1) || !vq->user_be;
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}
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#else
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static void vhost_disable_cross_endian(struct vhost_virtqueue *vq)
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{
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}
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static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp)
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{
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return -ENOIOCTLCMD;
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}
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static long vhost_get_vring_endian(struct vhost_virtqueue *vq, u32 idx,
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int __user *argp)
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{
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return -ENOIOCTLCMD;
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}
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static void vhost_init_is_le(struct vhost_virtqueue *vq)
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{
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vq->is_le = vhost_has_feature(vq, VIRTIO_F_VERSION_1)
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|| virtio_legacy_is_little_endian();
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}
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#endif /* CONFIG_VHOST_CROSS_ENDIAN_LEGACY */
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static void vhost_reset_is_le(struct vhost_virtqueue *vq)
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{
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vhost_init_is_le(vq);
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}
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struct vhost_flush_struct {
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struct vhost_work work;
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struct completion wait_event;
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};
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static void vhost_flush_work(struct vhost_work *work)
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{
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struct vhost_flush_struct *s;
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s = container_of(work, struct vhost_flush_struct, work);
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complete(&s->wait_event);
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}
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static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh,
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poll_table *pt)
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{
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struct vhost_poll *poll;
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poll = container_of(pt, struct vhost_poll, table);
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poll->wqh = wqh;
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add_wait_queue(wqh, &poll->wait);
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}
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static int vhost_poll_wakeup(wait_queue_entry_t *wait, unsigned mode, int sync,
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void *key)
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{
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struct vhost_poll *poll = container_of(wait, struct vhost_poll, wait);
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if (!(key_to_poll(key) & poll->mask))
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return 0;
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vhost_poll_queue(poll);
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return 0;
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}
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void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn)
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{
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clear_bit(VHOST_WORK_QUEUED, &work->flags);
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work->fn = fn;
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}
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EXPORT_SYMBOL_GPL(vhost_work_init);
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/* Init poll structure */
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void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
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__poll_t mask, struct vhost_dev *dev)
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{
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init_waitqueue_func_entry(&poll->wait, vhost_poll_wakeup);
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init_poll_funcptr(&poll->table, vhost_poll_func);
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poll->mask = mask;
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poll->dev = dev;
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poll->wqh = NULL;
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vhost_work_init(&poll->work, fn);
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}
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EXPORT_SYMBOL_GPL(vhost_poll_init);
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/* Start polling a file. We add ourselves to file's wait queue. The caller must
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* keep a reference to a file until after vhost_poll_stop is called. */
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int vhost_poll_start(struct vhost_poll *poll, struct file *file)
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{
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__poll_t mask;
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int ret = 0;
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if (poll->wqh)
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return 0;
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mask = vfs_poll(file, &poll->table);
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if (mask)
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vhost_poll_wakeup(&poll->wait, 0, 0, poll_to_key(mask));
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if (mask & EPOLLERR) {
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vhost_poll_stop(poll);
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ret = -EINVAL;
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}
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return ret;
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}
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EXPORT_SYMBOL_GPL(vhost_poll_start);
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/* Stop polling a file. After this function returns, it becomes safe to drop the
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* file reference. You must also flush afterwards. */
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void vhost_poll_stop(struct vhost_poll *poll)
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{
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if (poll->wqh) {
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remove_wait_queue(poll->wqh, &poll->wait);
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poll->wqh = NULL;
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}
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}
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EXPORT_SYMBOL_GPL(vhost_poll_stop);
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void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work)
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{
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struct vhost_flush_struct flush;
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if (dev->worker) {
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init_completion(&flush.wait_event);
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vhost_work_init(&flush.work, vhost_flush_work);
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vhost_work_queue(dev, &flush.work);
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wait_for_completion(&flush.wait_event);
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}
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}
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EXPORT_SYMBOL_GPL(vhost_work_flush);
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/* Flush any work that has been scheduled. When calling this, don't hold any
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* locks that are also used by the callback. */
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void vhost_poll_flush(struct vhost_poll *poll)
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{
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vhost_work_flush(poll->dev, &poll->work);
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}
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EXPORT_SYMBOL_GPL(vhost_poll_flush);
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void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work)
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{
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if (!dev->worker)
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return;
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if (!test_and_set_bit(VHOST_WORK_QUEUED, &work->flags)) {
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/* We can only add the work to the list after we're
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* sure it was not in the list.
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* test_and_set_bit() implies a memory barrier.
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*/
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llist_add(&work->node, &dev->work_list);
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wake_up_process(dev->worker);
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}
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}
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EXPORT_SYMBOL_GPL(vhost_work_queue);
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/* A lockless hint for busy polling code to exit the loop */
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bool vhost_has_work(struct vhost_dev *dev)
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{
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return !llist_empty(&dev->work_list);
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}
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EXPORT_SYMBOL_GPL(vhost_has_work);
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void vhost_poll_queue(struct vhost_poll *poll)
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{
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vhost_work_queue(poll->dev, &poll->work);
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}
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EXPORT_SYMBOL_GPL(vhost_poll_queue);
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static void __vhost_vq_meta_reset(struct vhost_virtqueue *vq)
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{
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int j;
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for (j = 0; j < VHOST_NUM_ADDRS; j++)
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vq->meta_iotlb[j] = NULL;
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}
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static void vhost_vq_meta_reset(struct vhost_dev *d)
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{
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int i;
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for (i = 0; i < d->nvqs; ++i) {
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mutex_lock(&d->vqs[i]->mutex);
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__vhost_vq_meta_reset(d->vqs[i]);
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mutex_unlock(&d->vqs[i]->mutex);
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}
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}
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static void vhost_vq_reset(struct vhost_dev *dev,
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struct vhost_virtqueue *vq)
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{
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vq->num = 1;
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vq->desc = NULL;
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vq->avail = NULL;
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vq->used = NULL;
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vq->last_avail_idx = 0;
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vq->avail_idx = 0;
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vq->last_used_idx = 0;
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vq->signalled_used = 0;
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vq->signalled_used_valid = false;
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vq->used_flags = 0;
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vq->log_used = false;
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vq->log_addr = -1ull;
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vq->private_data = NULL;
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vq->acked_features = 0;
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vq->acked_backend_features = 0;
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vq->log_base = NULL;
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vq->error_ctx = NULL;
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vq->kick = NULL;
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vq->call_ctx = NULL;
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vq->log_ctx = NULL;
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vhost_reset_is_le(vq);
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vhost_disable_cross_endian(vq);
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vq->busyloop_timeout = 0;
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vq->umem = NULL;
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vq->iotlb = NULL;
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__vhost_vq_meta_reset(vq);
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}
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static int vhost_worker(void *data)
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{
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struct vhost_dev *dev = data;
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struct vhost_work *work, *work_next;
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struct llist_node *node;
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mm_segment_t oldfs = get_fs();
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set_fs(USER_DS);
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use_mm(dev->mm);
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for (;;) {
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/* mb paired w/ kthread_stop */
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set_current_state(TASK_INTERRUPTIBLE);
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if (kthread_should_stop()) {
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__set_current_state(TASK_RUNNING);
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break;
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}
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node = llist_del_all(&dev->work_list);
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if (!node)
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schedule();
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node = llist_reverse_order(node);
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/* make sure flag is seen after deletion */
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smp_wmb();
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llist_for_each_entry_safe(work, work_next, node, node) {
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clear_bit(VHOST_WORK_QUEUED, &work->flags);
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__set_current_state(TASK_RUNNING);
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work->fn(work);
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if (need_resched())
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schedule();
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}
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}
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unuse_mm(dev->mm);
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set_fs(oldfs);
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return 0;
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}
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static void vhost_vq_free_iovecs(struct vhost_virtqueue *vq)
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{
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kfree(vq->indirect);
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vq->indirect = NULL;
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kfree(vq->log);
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vq->log = NULL;
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kfree(vq->heads);
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vq->heads = NULL;
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}
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/* Helper to allocate iovec buffers for all vqs. */
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static long vhost_dev_alloc_iovecs(struct vhost_dev *dev)
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{
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struct vhost_virtqueue *vq;
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int i;
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for (i = 0; i < dev->nvqs; ++i) {
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vq = dev->vqs[i];
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vq->indirect = kmalloc_array(UIO_MAXIOV,
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sizeof(*vq->indirect),
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GFP_KERNEL);
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vq->log = kmalloc_array(UIO_MAXIOV, sizeof(*vq->log),
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GFP_KERNEL);
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vq->heads = kmalloc_array(UIO_MAXIOV, sizeof(*vq->heads),
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GFP_KERNEL);
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if (!vq->indirect || !vq->log || !vq->heads)
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goto err_nomem;
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}
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return 0;
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err_nomem:
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for (; i >= 0; --i)
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vhost_vq_free_iovecs(dev->vqs[i]);
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return -ENOMEM;
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}
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static void vhost_dev_free_iovecs(struct vhost_dev *dev)
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{
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int i;
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for (i = 0; i < dev->nvqs; ++i)
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vhost_vq_free_iovecs(dev->vqs[i]);
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}
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void vhost_dev_init(struct vhost_dev *dev,
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struct vhost_virtqueue **vqs, int nvqs)
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{
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struct vhost_virtqueue *vq;
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int i;
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dev->vqs = vqs;
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dev->nvqs = nvqs;
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mutex_init(&dev->mutex);
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dev->log_ctx = NULL;
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dev->umem = NULL;
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dev->iotlb = NULL;
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dev->mm = NULL;
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dev->worker = NULL;
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init_llist_head(&dev->work_list);
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init_waitqueue_head(&dev->wait);
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INIT_LIST_HEAD(&dev->read_list);
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INIT_LIST_HEAD(&dev->pending_list);
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spin_lock_init(&dev->iotlb_lock);
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|
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for (i = 0; i < dev->nvqs; ++i) {
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vq = dev->vqs[i];
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vq->log = NULL;
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vq->indirect = NULL;
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vq->heads = NULL;
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vq->dev = dev;
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mutex_init(&vq->mutex);
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vhost_vq_reset(dev, vq);
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if (vq->handle_kick)
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vhost_poll_init(&vq->poll, vq->handle_kick,
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EPOLLIN, dev);
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}
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}
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EXPORT_SYMBOL_GPL(vhost_dev_init);
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/* Caller should have device mutex */
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long vhost_dev_check_owner(struct vhost_dev *dev)
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{
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/* Are you the owner? If not, I don't think you mean to do that */
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return dev->mm == current->mm ? 0 : -EPERM;
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}
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EXPORT_SYMBOL_GPL(vhost_dev_check_owner);
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struct vhost_attach_cgroups_struct {
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struct vhost_work work;
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struct task_struct *owner;
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int ret;
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};
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static void vhost_attach_cgroups_work(struct vhost_work *work)
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{
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struct vhost_attach_cgroups_struct *s;
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s = container_of(work, struct vhost_attach_cgroups_struct, work);
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s->ret = cgroup_attach_task_all(s->owner, current);
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}
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static int vhost_attach_cgroups(struct vhost_dev *dev)
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{
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struct vhost_attach_cgroups_struct attach;
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attach.owner = current;
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vhost_work_init(&attach.work, vhost_attach_cgroups_work);
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vhost_work_queue(dev, &attach.work);
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vhost_work_flush(dev, &attach.work);
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return attach.ret;
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}
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/* Caller should have device mutex */
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bool vhost_dev_has_owner(struct vhost_dev *dev)
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{
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return dev->mm;
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}
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EXPORT_SYMBOL_GPL(vhost_dev_has_owner);
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/* Caller should have device mutex */
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long vhost_dev_set_owner(struct vhost_dev *dev)
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{
|
|
struct task_struct *worker;
|
|
int err;
|
|
|
|
/* Is there an owner already? */
|
|
if (vhost_dev_has_owner(dev)) {
|
|
err = -EBUSY;
|
|
goto err_mm;
|
|
}
|
|
|
|
/* No owner, become one */
|
|
dev->mm = get_task_mm(current);
|
|
worker = kthread_create(vhost_worker, dev, "vhost-%d", current->pid);
|
|
if (IS_ERR(worker)) {
|
|
err = PTR_ERR(worker);
|
|
goto err_worker;
|
|
}
|
|
|
|
dev->worker = worker;
|
|
wake_up_process(worker); /* avoid contributing to loadavg */
|
|
|
|
err = vhost_attach_cgroups(dev);
|
|
if (err)
|
|
goto err_cgroup;
|
|
|
|
err = vhost_dev_alloc_iovecs(dev);
|
|
if (err)
|
|
goto err_cgroup;
|
|
|
|
return 0;
|
|
err_cgroup:
|
|
kthread_stop(worker);
|
|
dev->worker = NULL;
|
|
err_worker:
|
|
if (dev->mm)
|
|
mmput(dev->mm);
|
|
dev->mm = NULL;
|
|
err_mm:
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL_GPL(vhost_dev_set_owner);
|
|
|
|
struct vhost_umem *vhost_dev_reset_owner_prepare(void)
|
|
{
|
|
return kvzalloc(sizeof(struct vhost_umem), GFP_KERNEL);
|
|
}
|
|
EXPORT_SYMBOL_GPL(vhost_dev_reset_owner_prepare);
|
|
|
|
/* Caller should have device mutex */
|
|
void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_umem *umem)
|
|
{
|
|
int i;
|
|
|
|
vhost_dev_cleanup(dev);
|
|
|
|
/* Restore memory to default empty mapping. */
|
|
INIT_LIST_HEAD(&umem->umem_list);
|
|
dev->umem = umem;
|
|
/* We don't need VQ locks below since vhost_dev_cleanup makes sure
|
|
* VQs aren't running.
|
|
*/
|
|
for (i = 0; i < dev->nvqs; ++i)
|
|
dev->vqs[i]->umem = umem;
|
|
}
|
|
EXPORT_SYMBOL_GPL(vhost_dev_reset_owner);
|
|
|
|
void vhost_dev_stop(struct vhost_dev *dev)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < dev->nvqs; ++i) {
|
|
if (dev->vqs[i]->kick && dev->vqs[i]->handle_kick) {
|
|
vhost_poll_stop(&dev->vqs[i]->poll);
|
|
vhost_poll_flush(&dev->vqs[i]->poll);
|
|
}
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(vhost_dev_stop);
|
|
|
|
static void vhost_umem_free(struct vhost_umem *umem,
|
|
struct vhost_umem_node *node)
|
|
{
|
|
vhost_umem_interval_tree_remove(node, &umem->umem_tree);
|
|
list_del(&node->link);
|
|
kfree(node);
|
|
umem->numem--;
|
|
}
|
|
|
|
static void vhost_umem_clean(struct vhost_umem *umem)
|
|
{
|
|
struct vhost_umem_node *node, *tmp;
|
|
|
|
if (!umem)
|
|
return;
|
|
|
|
list_for_each_entry_safe(node, tmp, &umem->umem_list, link)
|
|
vhost_umem_free(umem, node);
|
|
|
|
kvfree(umem);
|
|
}
|
|
|
|
static void vhost_clear_msg(struct vhost_dev *dev)
|
|
{
|
|
struct vhost_msg_node *node, *n;
|
|
|
|
spin_lock(&dev->iotlb_lock);
|
|
|
|
list_for_each_entry_safe(node, n, &dev->read_list, node) {
|
|
list_del(&node->node);
|
|
kfree(node);
|
|
}
|
|
|
|
list_for_each_entry_safe(node, n, &dev->pending_list, node) {
|
|
list_del(&node->node);
|
|
kfree(node);
|
|
}
|
|
|
|
spin_unlock(&dev->iotlb_lock);
|
|
}
|
|
|
|
void vhost_dev_cleanup(struct vhost_dev *dev)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < dev->nvqs; ++i) {
|
|
if (dev->vqs[i]->error_ctx)
|
|
eventfd_ctx_put(dev->vqs[i]->error_ctx);
|
|
if (dev->vqs[i]->kick)
|
|
fput(dev->vqs[i]->kick);
|
|
if (dev->vqs[i]->call_ctx)
|
|
eventfd_ctx_put(dev->vqs[i]->call_ctx);
|
|
vhost_vq_reset(dev, dev->vqs[i]);
|
|
}
|
|
vhost_dev_free_iovecs(dev);
|
|
if (dev->log_ctx)
|
|
eventfd_ctx_put(dev->log_ctx);
|
|
dev->log_ctx = NULL;
|
|
/* No one will access memory at this point */
|
|
vhost_umem_clean(dev->umem);
|
|
dev->umem = NULL;
|
|
vhost_umem_clean(dev->iotlb);
|
|
dev->iotlb = NULL;
|
|
vhost_clear_msg(dev);
|
|
wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM);
|
|
WARN_ON(!llist_empty(&dev->work_list));
|
|
if (dev->worker) {
|
|
kthread_stop(dev->worker);
|
|
dev->worker = NULL;
|
|
}
|
|
if (dev->mm)
|
|
mmput(dev->mm);
|
|
dev->mm = NULL;
|
|
}
|
|
EXPORT_SYMBOL_GPL(vhost_dev_cleanup);
|
|
|
|
static bool log_access_ok(void __user *log_base, u64 addr, unsigned long sz)
|
|
{
|
|
u64 a = addr / VHOST_PAGE_SIZE / 8;
|
|
|
|
/* Make sure 64 bit math will not overflow. */
|
|
if (a > ULONG_MAX - (unsigned long)log_base ||
|
|
a + (unsigned long)log_base > ULONG_MAX)
|
|
return false;
|
|
|
|
return access_ok(VERIFY_WRITE, log_base + a,
|
|
(sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8);
|
|
}
|
|
|
|
static bool vhost_overflow(u64 uaddr, u64 size)
|
|
{
|
|
/* Make sure 64 bit math will not overflow. */
|
|
return uaddr > ULONG_MAX || size > ULONG_MAX || uaddr > ULONG_MAX - size;
|
|
}
|
|
|
|
/* Caller should have vq mutex and device mutex. */
|
|
static bool vq_memory_access_ok(void __user *log_base, struct vhost_umem *umem,
|
|
int log_all)
|
|
{
|
|
struct vhost_umem_node *node;
|
|
|
|
if (!umem)
|
|
return false;
|
|
|
|
list_for_each_entry(node, &umem->umem_list, link) {
|
|
unsigned long a = node->userspace_addr;
|
|
|
|
if (vhost_overflow(node->userspace_addr, node->size))
|
|
return false;
|
|
|
|
|
|
if (!access_ok(VERIFY_WRITE, (void __user *)a,
|
|
node->size))
|
|
return false;
|
|
else if (log_all && !log_access_ok(log_base,
|
|
node->start,
|
|
node->size))
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
static inline void __user *vhost_vq_meta_fetch(struct vhost_virtqueue *vq,
|
|
u64 addr, unsigned int size,
|
|
int type)
|
|
{
|
|
const struct vhost_umem_node *node = vq->meta_iotlb[type];
|
|
|
|
if (!node)
|
|
return NULL;
|
|
|
|
return (void *)(uintptr_t)(node->userspace_addr + addr - node->start);
|
|
}
|
|
|
|
/* Can we switch to this memory table? */
|
|
/* Caller should have device mutex but not vq mutex */
|
|
static bool memory_access_ok(struct vhost_dev *d, struct vhost_umem *umem,
|
|
int log_all)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < d->nvqs; ++i) {
|
|
bool ok;
|
|
bool log;
|
|
|
|
mutex_lock(&d->vqs[i]->mutex);
|
|
log = log_all || vhost_has_feature(d->vqs[i], VHOST_F_LOG_ALL);
|
|
/* If ring is inactive, will check when it's enabled. */
|
|
if (d->vqs[i]->private_data)
|
|
ok = vq_memory_access_ok(d->vqs[i]->log_base,
|
|
umem, log);
|
|
else
|
|
ok = true;
|
|
mutex_unlock(&d->vqs[i]->mutex);
|
|
if (!ok)
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
|
|
struct iovec iov[], int iov_size, int access);
|
|
|
|
static int vhost_copy_to_user(struct vhost_virtqueue *vq, void __user *to,
|
|
const void *from, unsigned size)
|
|
{
|
|
int ret;
|
|
|
|
if (!vq->iotlb)
|
|
return __copy_to_user(to, from, size);
|
|
else {
|
|
/* This function should be called after iotlb
|
|
* prefetch, which means we're sure that all vq
|
|
* could be access through iotlb. So -EAGAIN should
|
|
* not happen in this case.
|
|
*/
|
|
struct iov_iter t;
|
|
void __user *uaddr = vhost_vq_meta_fetch(vq,
|
|
(u64)(uintptr_t)to, size,
|
|
VHOST_ADDR_USED);
|
|
|
|
if (uaddr)
|
|
return __copy_to_user(uaddr, from, size);
|
|
|
|
ret = translate_desc(vq, (u64)(uintptr_t)to, size, vq->iotlb_iov,
|
|
ARRAY_SIZE(vq->iotlb_iov),
|
|
VHOST_ACCESS_WO);
|
|
if (ret < 0)
|
|
goto out;
|
|
iov_iter_init(&t, WRITE, vq->iotlb_iov, ret, size);
|
|
ret = copy_to_iter(from, size, &t);
|
|
if (ret == size)
|
|
ret = 0;
|
|
}
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
static int vhost_copy_from_user(struct vhost_virtqueue *vq, void *to,
|
|
void __user *from, unsigned size)
|
|
{
|
|
int ret;
|
|
|
|
if (!vq->iotlb)
|
|
return __copy_from_user(to, from, size);
|
|
else {
|
|
/* This function should be called after iotlb
|
|
* prefetch, which means we're sure that vq
|
|
* could be access through iotlb. So -EAGAIN should
|
|
* not happen in this case.
|
|
*/
|
|
void __user *uaddr = vhost_vq_meta_fetch(vq,
|
|
(u64)(uintptr_t)from, size,
|
|
VHOST_ADDR_DESC);
|
|
struct iov_iter f;
|
|
|
|
if (uaddr)
|
|
return __copy_from_user(to, uaddr, size);
|
|
|
|
ret = translate_desc(vq, (u64)(uintptr_t)from, size, vq->iotlb_iov,
|
|
ARRAY_SIZE(vq->iotlb_iov),
|
|
VHOST_ACCESS_RO);
|
|
if (ret < 0) {
|
|
vq_err(vq, "IOTLB translation failure: uaddr "
|
|
"%p size 0x%llx\n", from,
|
|
(unsigned long long) size);
|
|
goto out;
|
|
}
|
|
iov_iter_init(&f, READ, vq->iotlb_iov, ret, size);
|
|
ret = copy_from_iter(to, size, &f);
|
|
if (ret == size)
|
|
ret = 0;
|
|
}
|
|
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
static void __user *__vhost_get_user_slow(struct vhost_virtqueue *vq,
|
|
void __user *addr, unsigned int size,
|
|
int type)
|
|
{
|
|
int ret;
|
|
|
|
ret = translate_desc(vq, (u64)(uintptr_t)addr, size, vq->iotlb_iov,
|
|
ARRAY_SIZE(vq->iotlb_iov),
|
|
VHOST_ACCESS_RO);
|
|
if (ret < 0) {
|
|
vq_err(vq, "IOTLB translation failure: uaddr "
|
|
"%p size 0x%llx\n", addr,
|
|
(unsigned long long) size);
|
|
return NULL;
|
|
}
|
|
|
|
if (ret != 1 || vq->iotlb_iov[0].iov_len != size) {
|
|
vq_err(vq, "Non atomic userspace memory access: uaddr "
|
|
"%p size 0x%llx\n", addr,
|
|
(unsigned long long) size);
|
|
return NULL;
|
|
}
|
|
|
|
return vq->iotlb_iov[0].iov_base;
|
|
}
|
|
|
|
/* This function should be called after iotlb
|
|
* prefetch, which means we're sure that vq
|
|
* could be access through iotlb. So -EAGAIN should
|
|
* not happen in this case.
|
|
*/
|
|
static inline void __user *__vhost_get_user(struct vhost_virtqueue *vq,
|
|
void *addr, unsigned int size,
|
|
int type)
|
|
{
|
|
void __user *uaddr = vhost_vq_meta_fetch(vq,
|
|
(u64)(uintptr_t)addr, size, type);
|
|
if (uaddr)
|
|
return uaddr;
|
|
|
|
return __vhost_get_user_slow(vq, addr, size, type);
|
|
}
|
|
|
|
#define vhost_put_user(vq, x, ptr) \
|
|
({ \
|
|
int ret = -EFAULT; \
|
|
if (!vq->iotlb) { \
|
|
ret = __put_user(x, ptr); \
|
|
} else { \
|
|
__typeof__(ptr) to = \
|
|
(__typeof__(ptr)) __vhost_get_user(vq, ptr, \
|
|
sizeof(*ptr), VHOST_ADDR_USED); \
|
|
if (to != NULL) \
|
|
ret = __put_user(x, to); \
|
|
else \
|
|
ret = -EFAULT; \
|
|
} \
|
|
ret; \
|
|
})
|
|
|
|
#define vhost_get_user(vq, x, ptr, type) \
|
|
({ \
|
|
int ret; \
|
|
if (!vq->iotlb) { \
|
|
ret = __get_user(x, ptr); \
|
|
} else { \
|
|
__typeof__(ptr) from = \
|
|
(__typeof__(ptr)) __vhost_get_user(vq, ptr, \
|
|
sizeof(*ptr), \
|
|
type); \
|
|
if (from != NULL) \
|
|
ret = __get_user(x, from); \
|
|
else \
|
|
ret = -EFAULT; \
|
|
} \
|
|
ret; \
|
|
})
|
|
|
|
#define vhost_get_avail(vq, x, ptr) \
|
|
vhost_get_user(vq, x, ptr, VHOST_ADDR_AVAIL)
|
|
|
|
#define vhost_get_used(vq, x, ptr) \
|
|
vhost_get_user(vq, x, ptr, VHOST_ADDR_USED)
|
|
|
|
static int vhost_new_umem_range(struct vhost_umem *umem,
|
|
u64 start, u64 size, u64 end,
|
|
u64 userspace_addr, int perm)
|
|
{
|
|
struct vhost_umem_node *tmp, *node = kmalloc(sizeof(*node), GFP_ATOMIC);
|
|
|
|
if (!node)
|
|
return -ENOMEM;
|
|
|
|
if (umem->numem == max_iotlb_entries) {
|
|
tmp = list_first_entry(&umem->umem_list, typeof(*tmp), link);
|
|
vhost_umem_free(umem, tmp);
|
|
}
|
|
|
|
node->start = start;
|
|
node->size = size;
|
|
node->last = end;
|
|
node->userspace_addr = userspace_addr;
|
|
node->perm = perm;
|
|
INIT_LIST_HEAD(&node->link);
|
|
list_add_tail(&node->link, &umem->umem_list);
|
|
vhost_umem_interval_tree_insert(node, &umem->umem_tree);
|
|
umem->numem++;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void vhost_del_umem_range(struct vhost_umem *umem,
|
|
u64 start, u64 end)
|
|
{
|
|
struct vhost_umem_node *node;
|
|
|
|
while ((node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
|
|
start, end)))
|
|
vhost_umem_free(umem, node);
|
|
}
|
|
|
|
static void vhost_iotlb_notify_vq(struct vhost_dev *d,
|
|
struct vhost_iotlb_msg *msg)
|
|
{
|
|
struct vhost_msg_node *node, *n;
|
|
|
|
spin_lock(&d->iotlb_lock);
|
|
|
|
list_for_each_entry_safe(node, n, &d->pending_list, node) {
|
|
struct vhost_iotlb_msg *vq_msg = &node->msg.iotlb;
|
|
if (msg->iova <= vq_msg->iova &&
|
|
msg->iova + msg->size - 1 >= vq_msg->iova &&
|
|
vq_msg->type == VHOST_IOTLB_MISS) {
|
|
mutex_lock(&node->vq->mutex);
|
|
vhost_poll_queue(&node->vq->poll);
|
|
mutex_unlock(&node->vq->mutex);
|
|
|
|
list_del(&node->node);
|
|
kfree(node);
|
|
}
|
|
}
|
|
|
|
spin_unlock(&d->iotlb_lock);
|
|
}
|
|
|
|
static bool umem_access_ok(u64 uaddr, u64 size, int access)
|
|
{
|
|
unsigned long a = uaddr;
|
|
|
|
/* Make sure 64 bit math will not overflow. */
|
|
if (vhost_overflow(uaddr, size))
|
|
return false;
|
|
|
|
if ((access & VHOST_ACCESS_RO) &&
|
|
!access_ok(VERIFY_READ, (void __user *)a, size))
|
|
return false;
|
|
if ((access & VHOST_ACCESS_WO) &&
|
|
!access_ok(VERIFY_WRITE, (void __user *)a, size))
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
static int vhost_process_iotlb_msg(struct vhost_dev *dev,
|
|
struct vhost_iotlb_msg *msg)
|
|
{
|
|
int ret = 0;
|
|
|
|
mutex_lock(&dev->mutex);
|
|
switch (msg->type) {
|
|
case VHOST_IOTLB_UPDATE:
|
|
if (!dev->iotlb) {
|
|
ret = -EFAULT;
|
|
break;
|
|
}
|
|
if (!umem_access_ok(msg->uaddr, msg->size, msg->perm)) {
|
|
ret = -EFAULT;
|
|
break;
|
|
}
|
|
vhost_vq_meta_reset(dev);
|
|
if (vhost_new_umem_range(dev->iotlb, msg->iova, msg->size,
|
|
msg->iova + msg->size - 1,
|
|
msg->uaddr, msg->perm)) {
|
|
ret = -ENOMEM;
|
|
break;
|
|
}
|
|
vhost_iotlb_notify_vq(dev, msg);
|
|
break;
|
|
case VHOST_IOTLB_INVALIDATE:
|
|
if (!dev->iotlb) {
|
|
ret = -EFAULT;
|
|
break;
|
|
}
|
|
vhost_vq_meta_reset(dev);
|
|
vhost_del_umem_range(dev->iotlb, msg->iova,
|
|
msg->iova + msg->size - 1);
|
|
break;
|
|
default:
|
|
ret = -EINVAL;
|
|
break;
|
|
}
|
|
|
|
mutex_unlock(&dev->mutex);
|
|
|
|
return ret;
|
|
}
|
|
ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
|
|
struct iov_iter *from)
|
|
{
|
|
struct vhost_iotlb_msg msg;
|
|
size_t offset;
|
|
int type, ret;
|
|
|
|
ret = copy_from_iter(&type, sizeof(type), from);
|
|
if (ret != sizeof(type))
|
|
goto done;
|
|
|
|
switch (type) {
|
|
case VHOST_IOTLB_MSG:
|
|
/* There maybe a hole after type for V1 message type,
|
|
* so skip it here.
|
|
*/
|
|
offset = offsetof(struct vhost_msg, iotlb) - sizeof(int);
|
|
break;
|
|
case VHOST_IOTLB_MSG_V2:
|
|
offset = sizeof(__u32);
|
|
break;
|
|
default:
|
|
ret = -EINVAL;
|
|
goto done;
|
|
}
|
|
|
|
iov_iter_advance(from, offset);
|
|
ret = copy_from_iter(&msg, sizeof(msg), from);
|
|
if (ret != sizeof(msg))
|
|
goto done;
|
|
if (vhost_process_iotlb_msg(dev, &msg)) {
|
|
ret = -EFAULT;
|
|
goto done;
|
|
}
|
|
|
|
ret = (type == VHOST_IOTLB_MSG) ? sizeof(struct vhost_msg) :
|
|
sizeof(struct vhost_msg_v2);
|
|
done:
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(vhost_chr_write_iter);
|
|
|
|
__poll_t vhost_chr_poll(struct file *file, struct vhost_dev *dev,
|
|
poll_table *wait)
|
|
{
|
|
__poll_t mask = 0;
|
|
|
|
poll_wait(file, &dev->wait, wait);
|
|
|
|
if (!list_empty(&dev->read_list))
|
|
mask |= EPOLLIN | EPOLLRDNORM;
|
|
|
|
return mask;
|
|
}
|
|
EXPORT_SYMBOL(vhost_chr_poll);
|
|
|
|
ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to,
|
|
int noblock)
|
|
{
|
|
DEFINE_WAIT(wait);
|
|
struct vhost_msg_node *node;
|
|
ssize_t ret = 0;
|
|
unsigned size = sizeof(struct vhost_msg);
|
|
|
|
if (iov_iter_count(to) < size)
|
|
return 0;
|
|
|
|
while (1) {
|
|
if (!noblock)
|
|
prepare_to_wait(&dev->wait, &wait,
|
|
TASK_INTERRUPTIBLE);
|
|
|
|
node = vhost_dequeue_msg(dev, &dev->read_list);
|
|
if (node)
|
|
break;
|
|
if (noblock) {
|
|
ret = -EAGAIN;
|
|
break;
|
|
}
|
|
if (signal_pending(current)) {
|
|
ret = -ERESTARTSYS;
|
|
break;
|
|
}
|
|
if (!dev->iotlb) {
|
|
ret = -EBADFD;
|
|
break;
|
|
}
|
|
|
|
schedule();
|
|
}
|
|
|
|
if (!noblock)
|
|
finish_wait(&dev->wait, &wait);
|
|
|
|
if (node) {
|
|
struct vhost_iotlb_msg *msg;
|
|
void *start = &node->msg;
|
|
|
|
switch (node->msg.type) {
|
|
case VHOST_IOTLB_MSG:
|
|
size = sizeof(node->msg);
|
|
msg = &node->msg.iotlb;
|
|
break;
|
|
case VHOST_IOTLB_MSG_V2:
|
|
size = sizeof(node->msg_v2);
|
|
msg = &node->msg_v2.iotlb;
|
|
break;
|
|
default:
|
|
BUG();
|
|
break;
|
|
}
|
|
|
|
ret = copy_to_iter(start, size, to);
|
|
if (ret != size || msg->type != VHOST_IOTLB_MISS) {
|
|
kfree(node);
|
|
return ret;
|
|
}
|
|
vhost_enqueue_msg(dev, &dev->pending_list, node);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(vhost_chr_read_iter);
|
|
|
|
static int vhost_iotlb_miss(struct vhost_virtqueue *vq, u64 iova, int access)
|
|
{
|
|
struct vhost_dev *dev = vq->dev;
|
|
struct vhost_msg_node *node;
|
|
struct vhost_iotlb_msg *msg;
|
|
bool v2 = vhost_backend_has_feature(vq, VHOST_BACKEND_F_IOTLB_MSG_V2);
|
|
|
|
node = vhost_new_msg(vq, v2 ? VHOST_IOTLB_MSG_V2 : VHOST_IOTLB_MSG);
|
|
if (!node)
|
|
return -ENOMEM;
|
|
|
|
if (v2) {
|
|
node->msg_v2.type = VHOST_IOTLB_MSG_V2;
|
|
msg = &node->msg_v2.iotlb;
|
|
} else {
|
|
msg = &node->msg.iotlb;
|
|
}
|
|
|
|
msg->type = VHOST_IOTLB_MISS;
|
|
msg->iova = iova;
|
|
msg->perm = access;
|
|
|
|
vhost_enqueue_msg(dev, &dev->read_list, node);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static bool vq_access_ok(struct vhost_virtqueue *vq, unsigned int num,
|
|
struct vring_desc __user *desc,
|
|
struct vring_avail __user *avail,
|
|
struct vring_used __user *used)
|
|
|
|
{
|
|
size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
|
|
|
|
return access_ok(VERIFY_READ, desc, num * sizeof *desc) &&
|
|
access_ok(VERIFY_READ, avail,
|
|
sizeof *avail + num * sizeof *avail->ring + s) &&
|
|
access_ok(VERIFY_WRITE, used,
|
|
sizeof *used + num * sizeof *used->ring + s);
|
|
}
|
|
|
|
static void vhost_vq_meta_update(struct vhost_virtqueue *vq,
|
|
const struct vhost_umem_node *node,
|
|
int type)
|
|
{
|
|
int access = (type == VHOST_ADDR_USED) ?
|
|
VHOST_ACCESS_WO : VHOST_ACCESS_RO;
|
|
|
|
if (likely(node->perm & access))
|
|
vq->meta_iotlb[type] = node;
|
|
}
|
|
|
|
static bool iotlb_access_ok(struct vhost_virtqueue *vq,
|
|
int access, u64 addr, u64 len, int type)
|
|
{
|
|
const struct vhost_umem_node *node;
|
|
struct vhost_umem *umem = vq->iotlb;
|
|
u64 s = 0, size, orig_addr = addr, last = addr + len - 1;
|
|
|
|
if (vhost_vq_meta_fetch(vq, addr, len, type))
|
|
return true;
|
|
|
|
while (len > s) {
|
|
node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
|
|
addr,
|
|
last);
|
|
if (node == NULL || node->start > addr) {
|
|
vhost_iotlb_miss(vq, addr, access);
|
|
return false;
|
|
} else if (!(node->perm & access)) {
|
|
/* Report the possible access violation by
|
|
* request another translation from userspace.
|
|
*/
|
|
return false;
|
|
}
|
|
|
|
size = node->size - addr + node->start;
|
|
|
|
if (orig_addr == addr && size >= len)
|
|
vhost_vq_meta_update(vq, node, type);
|
|
|
|
s += size;
|
|
addr += size;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
int vq_iotlb_prefetch(struct vhost_virtqueue *vq)
|
|
{
|
|
size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
|
|
unsigned int num = vq->num;
|
|
|
|
if (!vq->iotlb)
|
|
return 1;
|
|
|
|
return iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->desc,
|
|
num * sizeof(*vq->desc), VHOST_ADDR_DESC) &&
|
|
iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->avail,
|
|
sizeof *vq->avail +
|
|
num * sizeof(*vq->avail->ring) + s,
|
|
VHOST_ADDR_AVAIL) &&
|
|
iotlb_access_ok(vq, VHOST_ACCESS_WO, (u64)(uintptr_t)vq->used,
|
|
sizeof *vq->used +
|
|
num * sizeof(*vq->used->ring) + s,
|
|
VHOST_ADDR_USED);
|
|
}
|
|
EXPORT_SYMBOL_GPL(vq_iotlb_prefetch);
|
|
|
|
/* Can we log writes? */
|
|
/* Caller should have device mutex but not vq mutex */
|
|
bool vhost_log_access_ok(struct vhost_dev *dev)
|
|
{
|
|
return memory_access_ok(dev, dev->umem, 1);
|
|
}
|
|
EXPORT_SYMBOL_GPL(vhost_log_access_ok);
|
|
|
|
/* Verify access for write logging. */
|
|
/* Caller should have vq mutex and device mutex */
|
|
static bool vq_log_access_ok(struct vhost_virtqueue *vq,
|
|
void __user *log_base)
|
|
{
|
|
size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
|
|
|
|
return vq_memory_access_ok(log_base, vq->umem,
|
|
vhost_has_feature(vq, VHOST_F_LOG_ALL)) &&
|
|
(!vq->log_used || log_access_ok(log_base, vq->log_addr,
|
|
sizeof *vq->used +
|
|
vq->num * sizeof *vq->used->ring + s));
|
|
}
|
|
|
|
/* Can we start vq? */
|
|
/* Caller should have vq mutex and device mutex */
|
|
bool vhost_vq_access_ok(struct vhost_virtqueue *vq)
|
|
{
|
|
if (!vq_log_access_ok(vq, vq->log_base))
|
|
return false;
|
|
|
|
/* Access validation occurs at prefetch time with IOTLB */
|
|
if (vq->iotlb)
|
|
return true;
|
|
|
|
return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used);
|
|
}
|
|
EXPORT_SYMBOL_GPL(vhost_vq_access_ok);
|
|
|
|
static struct vhost_umem *vhost_umem_alloc(void)
|
|
{
|
|
struct vhost_umem *umem = kvzalloc(sizeof(*umem), GFP_KERNEL);
|
|
|
|
if (!umem)
|
|
return NULL;
|
|
|
|
umem->umem_tree = RB_ROOT_CACHED;
|
|
umem->numem = 0;
|
|
INIT_LIST_HEAD(&umem->umem_list);
|
|
|
|
return umem;
|
|
}
|
|
|
|
static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
|
|
{
|
|
struct vhost_memory mem, *newmem;
|
|
struct vhost_memory_region *region;
|
|
struct vhost_umem *newumem, *oldumem;
|
|
unsigned long size = offsetof(struct vhost_memory, regions);
|
|
int i;
|
|
|
|
if (copy_from_user(&mem, m, size))
|
|
return -EFAULT;
|
|
if (mem.padding)
|
|
return -EOPNOTSUPP;
|
|
if (mem.nregions > max_mem_regions)
|
|
return -E2BIG;
|
|
newmem = kvzalloc(struct_size(newmem, regions, mem.nregions),
|
|
GFP_KERNEL);
|
|
if (!newmem)
|
|
return -ENOMEM;
|
|
|
|
memcpy(newmem, &mem, size);
|
|
if (copy_from_user(newmem->regions, m->regions,
|
|
mem.nregions * sizeof *m->regions)) {
|
|
kvfree(newmem);
|
|
return -EFAULT;
|
|
}
|
|
|
|
newumem = vhost_umem_alloc();
|
|
if (!newumem) {
|
|
kvfree(newmem);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
for (region = newmem->regions;
|
|
region < newmem->regions + mem.nregions;
|
|
region++) {
|
|
if (vhost_new_umem_range(newumem,
|
|
region->guest_phys_addr,
|
|
region->memory_size,
|
|
region->guest_phys_addr +
|
|
region->memory_size - 1,
|
|
region->userspace_addr,
|
|
VHOST_ACCESS_RW))
|
|
goto err;
|
|
}
|
|
|
|
if (!memory_access_ok(d, newumem, 0))
|
|
goto err;
|
|
|
|
oldumem = d->umem;
|
|
d->umem = newumem;
|
|
|
|
/* All memory accesses are done under some VQ mutex. */
|
|
for (i = 0; i < d->nvqs; ++i) {
|
|
mutex_lock(&d->vqs[i]->mutex);
|
|
d->vqs[i]->umem = newumem;
|
|
mutex_unlock(&d->vqs[i]->mutex);
|
|
}
|
|
|
|
kvfree(newmem);
|
|
vhost_umem_clean(oldumem);
|
|
return 0;
|
|
|
|
err:
|
|
vhost_umem_clean(newumem);
|
|
kvfree(newmem);
|
|
return -EFAULT;
|
|
}
|
|
|
|
long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
|
|
{
|
|
struct file *eventfp, *filep = NULL;
|
|
bool pollstart = false, pollstop = false;
|
|
struct eventfd_ctx *ctx = NULL;
|
|
u32 __user *idxp = argp;
|
|
struct vhost_virtqueue *vq;
|
|
struct vhost_vring_state s;
|
|
struct vhost_vring_file f;
|
|
struct vhost_vring_addr a;
|
|
u32 idx;
|
|
long r;
|
|
|
|
r = get_user(idx, idxp);
|
|
if (r < 0)
|
|
return r;
|
|
if (idx >= d->nvqs)
|
|
return -ENOBUFS;
|
|
|
|
idx = array_index_nospec(idx, d->nvqs);
|
|
vq = d->vqs[idx];
|
|
|
|
mutex_lock(&vq->mutex);
|
|
|
|
switch (ioctl) {
|
|
case VHOST_SET_VRING_NUM:
|
|
/* Resizing ring with an active backend?
|
|
* You don't want to do that. */
|
|
if (vq->private_data) {
|
|
r = -EBUSY;
|
|
break;
|
|
}
|
|
if (copy_from_user(&s, argp, sizeof s)) {
|
|
r = -EFAULT;
|
|
break;
|
|
}
|
|
if (!s.num || s.num > 0xffff || (s.num & (s.num - 1))) {
|
|
r = -EINVAL;
|
|
break;
|
|
}
|
|
vq->num = s.num;
|
|
break;
|
|
case VHOST_SET_VRING_BASE:
|
|
/* Moving base with an active backend?
|
|
* You don't want to do that. */
|
|
if (vq->private_data) {
|
|
r = -EBUSY;
|
|
break;
|
|
}
|
|
if (copy_from_user(&s, argp, sizeof s)) {
|
|
r = -EFAULT;
|
|
break;
|
|
}
|
|
if (s.num > 0xffff) {
|
|
r = -EINVAL;
|
|
break;
|
|
}
|
|
vq->last_avail_idx = s.num;
|
|
/* Forget the cached index value. */
|
|
vq->avail_idx = vq->last_avail_idx;
|
|
break;
|
|
case VHOST_GET_VRING_BASE:
|
|
s.index = idx;
|
|
s.num = vq->last_avail_idx;
|
|
if (copy_to_user(argp, &s, sizeof s))
|
|
r = -EFAULT;
|
|
break;
|
|
case VHOST_SET_VRING_ADDR:
|
|
if (copy_from_user(&a, argp, sizeof a)) {
|
|
r = -EFAULT;
|
|
break;
|
|
}
|
|
if (a.flags & ~(0x1 << VHOST_VRING_F_LOG)) {
|
|
r = -EOPNOTSUPP;
|
|
break;
|
|
}
|
|
/* For 32bit, verify that the top 32bits of the user
|
|
data are set to zero. */
|
|
if ((u64)(unsigned long)a.desc_user_addr != a.desc_user_addr ||
|
|
(u64)(unsigned long)a.used_user_addr != a.used_user_addr ||
|
|
(u64)(unsigned long)a.avail_user_addr != a.avail_user_addr) {
|
|
r = -EFAULT;
|
|
break;
|
|
}
|
|
|
|
/* Make sure it's safe to cast pointers to vring types. */
|
|
BUILD_BUG_ON(__alignof__ *vq->avail > VRING_AVAIL_ALIGN_SIZE);
|
|
BUILD_BUG_ON(__alignof__ *vq->used > VRING_USED_ALIGN_SIZE);
|
|
if ((a.avail_user_addr & (VRING_AVAIL_ALIGN_SIZE - 1)) ||
|
|
(a.used_user_addr & (VRING_USED_ALIGN_SIZE - 1)) ||
|
|
(a.log_guest_addr & (VRING_USED_ALIGN_SIZE - 1))) {
|
|
r = -EINVAL;
|
|
break;
|
|
}
|
|
|
|
/* We only verify access here if backend is configured.
|
|
* If it is not, we don't as size might not have been setup.
|
|
* We will verify when backend is configured. */
|
|
if (vq->private_data) {
|
|
if (!vq_access_ok(vq, vq->num,
|
|
(void __user *)(unsigned long)a.desc_user_addr,
|
|
(void __user *)(unsigned long)a.avail_user_addr,
|
|
(void __user *)(unsigned long)a.used_user_addr)) {
|
|
r = -EINVAL;
|
|
break;
|
|
}
|
|
|
|
/* Also validate log access for used ring if enabled. */
|
|
if ((a.flags & (0x1 << VHOST_VRING_F_LOG)) &&
|
|
!log_access_ok(vq->log_base, a.log_guest_addr,
|
|
sizeof *vq->used +
|
|
vq->num * sizeof *vq->used->ring)) {
|
|
r = -EINVAL;
|
|
break;
|
|
}
|
|
}
|
|
|
|
vq->log_used = !!(a.flags & (0x1 << VHOST_VRING_F_LOG));
|
|
vq->desc = (void __user *)(unsigned long)a.desc_user_addr;
|
|
vq->avail = (void __user *)(unsigned long)a.avail_user_addr;
|
|
vq->log_addr = a.log_guest_addr;
|
|
vq->used = (void __user *)(unsigned long)a.used_user_addr;
|
|
break;
|
|
case VHOST_SET_VRING_KICK:
|
|
if (copy_from_user(&f, argp, sizeof f)) {
|
|
r = -EFAULT;
|
|
break;
|
|
}
|
|
eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd);
|
|
if (IS_ERR(eventfp)) {
|
|
r = PTR_ERR(eventfp);
|
|
break;
|
|
}
|
|
if (eventfp != vq->kick) {
|
|
pollstop = (filep = vq->kick) != NULL;
|
|
pollstart = (vq->kick = eventfp) != NULL;
|
|
} else
|
|
filep = eventfp;
|
|
break;
|
|
case VHOST_SET_VRING_CALL:
|
|
if (copy_from_user(&f, argp, sizeof f)) {
|
|
r = -EFAULT;
|
|
break;
|
|
}
|
|
ctx = f.fd == -1 ? NULL : eventfd_ctx_fdget(f.fd);
|
|
if (IS_ERR(ctx)) {
|
|
r = PTR_ERR(ctx);
|
|
break;
|
|
}
|
|
swap(ctx, vq->call_ctx);
|
|
break;
|
|
case VHOST_SET_VRING_ERR:
|
|
if (copy_from_user(&f, argp, sizeof f)) {
|
|
r = -EFAULT;
|
|
break;
|
|
}
|
|
ctx = f.fd == -1 ? NULL : eventfd_ctx_fdget(f.fd);
|
|
if (IS_ERR(ctx)) {
|
|
r = PTR_ERR(ctx);
|
|
break;
|
|
}
|
|
swap(ctx, vq->error_ctx);
|
|
break;
|
|
case VHOST_SET_VRING_ENDIAN:
|
|
r = vhost_set_vring_endian(vq, argp);
|
|
break;
|
|
case VHOST_GET_VRING_ENDIAN:
|
|
r = vhost_get_vring_endian(vq, idx, argp);
|
|
break;
|
|
case VHOST_SET_VRING_BUSYLOOP_TIMEOUT:
|
|
if (copy_from_user(&s, argp, sizeof(s))) {
|
|
r = -EFAULT;
|
|
break;
|
|
}
|
|
vq->busyloop_timeout = s.num;
|
|
break;
|
|
case VHOST_GET_VRING_BUSYLOOP_TIMEOUT:
|
|
s.index = idx;
|
|
s.num = vq->busyloop_timeout;
|
|
if (copy_to_user(argp, &s, sizeof(s)))
|
|
r = -EFAULT;
|
|
break;
|
|
default:
|
|
r = -ENOIOCTLCMD;
|
|
}
|
|
|
|
if (pollstop && vq->handle_kick)
|
|
vhost_poll_stop(&vq->poll);
|
|
|
|
if (!IS_ERR_OR_NULL(ctx))
|
|
eventfd_ctx_put(ctx);
|
|
if (filep)
|
|
fput(filep);
|
|
|
|
if (pollstart && vq->handle_kick)
|
|
r = vhost_poll_start(&vq->poll, vq->kick);
|
|
|
|
mutex_unlock(&vq->mutex);
|
|
|
|
if (pollstop && vq->handle_kick)
|
|
vhost_poll_flush(&vq->poll);
|
|
return r;
|
|
}
|
|
EXPORT_SYMBOL_GPL(vhost_vring_ioctl);
|
|
|
|
int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled)
|
|
{
|
|
struct vhost_umem *niotlb, *oiotlb;
|
|
int i;
|
|
|
|
niotlb = vhost_umem_alloc();
|
|
if (!niotlb)
|
|
return -ENOMEM;
|
|
|
|
oiotlb = d->iotlb;
|
|
d->iotlb = niotlb;
|
|
|
|
for (i = 0; i < d->nvqs; ++i) {
|
|
struct vhost_virtqueue *vq = d->vqs[i];
|
|
|
|
mutex_lock(&vq->mutex);
|
|
vq->iotlb = niotlb;
|
|
__vhost_vq_meta_reset(vq);
|
|
mutex_unlock(&vq->mutex);
|
|
}
|
|
|
|
vhost_umem_clean(oiotlb);
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(vhost_init_device_iotlb);
|
|
|
|
/* Caller must have device mutex */
|
|
long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
|
|
{
|
|
struct eventfd_ctx *ctx;
|
|
u64 p;
|
|
long r;
|
|
int i, fd;
|
|
|
|
/* If you are not the owner, you can become one */
|
|
if (ioctl == VHOST_SET_OWNER) {
|
|
r = vhost_dev_set_owner(d);
|
|
goto done;
|
|
}
|
|
|
|
/* You must be the owner to do anything else */
|
|
r = vhost_dev_check_owner(d);
|
|
if (r)
|
|
goto done;
|
|
|
|
switch (ioctl) {
|
|
case VHOST_SET_MEM_TABLE:
|
|
r = vhost_set_memory(d, argp);
|
|
break;
|
|
case VHOST_SET_LOG_BASE:
|
|
if (copy_from_user(&p, argp, sizeof p)) {
|
|
r = -EFAULT;
|
|
break;
|
|
}
|
|
if ((u64)(unsigned long)p != p) {
|
|
r = -EFAULT;
|
|
break;
|
|
}
|
|
for (i = 0; i < d->nvqs; ++i) {
|
|
struct vhost_virtqueue *vq;
|
|
void __user *base = (void __user *)(unsigned long)p;
|
|
vq = d->vqs[i];
|
|
mutex_lock(&vq->mutex);
|
|
/* If ring is inactive, will check when it's enabled. */
|
|
if (vq->private_data && !vq_log_access_ok(vq, base))
|
|
r = -EFAULT;
|
|
else
|
|
vq->log_base = base;
|
|
mutex_unlock(&vq->mutex);
|
|
}
|
|
break;
|
|
case VHOST_SET_LOG_FD:
|
|
r = get_user(fd, (int __user *)argp);
|
|
if (r < 0)
|
|
break;
|
|
ctx = fd == -1 ? NULL : eventfd_ctx_fdget(fd);
|
|
if (IS_ERR(ctx)) {
|
|
r = PTR_ERR(ctx);
|
|
break;
|
|
}
|
|
swap(ctx, d->log_ctx);
|
|
for (i = 0; i < d->nvqs; ++i) {
|
|
mutex_lock(&d->vqs[i]->mutex);
|
|
d->vqs[i]->log_ctx = d->log_ctx;
|
|
mutex_unlock(&d->vqs[i]->mutex);
|
|
}
|
|
if (ctx)
|
|
eventfd_ctx_put(ctx);
|
|
break;
|
|
default:
|
|
r = -ENOIOCTLCMD;
|
|
break;
|
|
}
|
|
done:
|
|
return r;
|
|
}
|
|
EXPORT_SYMBOL_GPL(vhost_dev_ioctl);
|
|
|
|
/* TODO: This is really inefficient. We need something like get_user()
|
|
* (instruction directly accesses the data, with an exception table entry
|
|
* returning -EFAULT). See Documentation/x86/exception-tables.txt.
|
|
*/
|
|
static int set_bit_to_user(int nr, void __user *addr)
|
|
{
|
|
unsigned long log = (unsigned long)addr;
|
|
struct page *page;
|
|
void *base;
|
|
int bit = nr + (log % PAGE_SIZE) * 8;
|
|
int r;
|
|
|
|
r = get_user_pages_fast(log, 1, 1, &page);
|
|
if (r < 0)
|
|
return r;
|
|
BUG_ON(r != 1);
|
|
base = kmap_atomic(page);
|
|
set_bit(bit, base);
|
|
kunmap_atomic(base);
|
|
set_page_dirty_lock(page);
|
|
put_page(page);
|
|
return 0;
|
|
}
|
|
|
|
static int log_write(void __user *log_base,
|
|
u64 write_address, u64 write_length)
|
|
{
|
|
u64 write_page = write_address / VHOST_PAGE_SIZE;
|
|
int r;
|
|
|
|
if (!write_length)
|
|
return 0;
|
|
write_length += write_address % VHOST_PAGE_SIZE;
|
|
for (;;) {
|
|
u64 base = (u64)(unsigned long)log_base;
|
|
u64 log = base + write_page / 8;
|
|
int bit = write_page % 8;
|
|
if ((u64)(unsigned long)log != log)
|
|
return -EFAULT;
|
|
r = set_bit_to_user(bit, (void __user *)(unsigned long)log);
|
|
if (r < 0)
|
|
return r;
|
|
if (write_length <= VHOST_PAGE_SIZE)
|
|
break;
|
|
write_length -= VHOST_PAGE_SIZE;
|
|
write_page += 1;
|
|
}
|
|
return r;
|
|
}
|
|
|
|
int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
|
|
unsigned int log_num, u64 len)
|
|
{
|
|
int i, r;
|
|
|
|
/* Make sure data written is seen before log. */
|
|
smp_wmb();
|
|
for (i = 0; i < log_num; ++i) {
|
|
u64 l = min(log[i].len, len);
|
|
r = log_write(vq->log_base, log[i].addr, l);
|
|
if (r < 0)
|
|
return r;
|
|
len -= l;
|
|
if (!len) {
|
|
if (vq->log_ctx)
|
|
eventfd_signal(vq->log_ctx, 1);
|
|
return 0;
|
|
}
|
|
}
|
|
/* Length written exceeds what we have stored. This is a bug. */
|
|
BUG();
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(vhost_log_write);
|
|
|
|
static int vhost_update_used_flags(struct vhost_virtqueue *vq)
|
|
{
|
|
void __user *used;
|
|
if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->used_flags),
|
|
&vq->used->flags) < 0)
|
|
return -EFAULT;
|
|
if (unlikely(vq->log_used)) {
|
|
/* Make sure the flag is seen before log. */
|
|
smp_wmb();
|
|
/* Log used flag write. */
|
|
used = &vq->used->flags;
|
|
log_write(vq->log_base, vq->log_addr +
|
|
(used - (void __user *)vq->used),
|
|
sizeof vq->used->flags);
|
|
if (vq->log_ctx)
|
|
eventfd_signal(vq->log_ctx, 1);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event)
|
|
{
|
|
if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->avail_idx),
|
|
vhost_avail_event(vq)))
|
|
return -EFAULT;
|
|
if (unlikely(vq->log_used)) {
|
|
void __user *used;
|
|
/* Make sure the event is seen before log. */
|
|
smp_wmb();
|
|
/* Log avail event write */
|
|
used = vhost_avail_event(vq);
|
|
log_write(vq->log_base, vq->log_addr +
|
|
(used - (void __user *)vq->used),
|
|
sizeof *vhost_avail_event(vq));
|
|
if (vq->log_ctx)
|
|
eventfd_signal(vq->log_ctx, 1);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
int vhost_vq_init_access(struct vhost_virtqueue *vq)
|
|
{
|
|
__virtio16 last_used_idx;
|
|
int r;
|
|
bool is_le = vq->is_le;
|
|
|
|
if (!vq->private_data)
|
|
return 0;
|
|
|
|
vhost_init_is_le(vq);
|
|
|
|
r = vhost_update_used_flags(vq);
|
|
if (r)
|
|
goto err;
|
|
vq->signalled_used_valid = false;
|
|
if (!vq->iotlb &&
|
|
!access_ok(VERIFY_READ, &vq->used->idx, sizeof vq->used->idx)) {
|
|
r = -EFAULT;
|
|
goto err;
|
|
}
|
|
r = vhost_get_used(vq, last_used_idx, &vq->used->idx);
|
|
if (r) {
|
|
vq_err(vq, "Can't access used idx at %p\n",
|
|
&vq->used->idx);
|
|
goto err;
|
|
}
|
|
vq->last_used_idx = vhost16_to_cpu(vq, last_used_idx);
|
|
return 0;
|
|
|
|
err:
|
|
vq->is_le = is_le;
|
|
return r;
|
|
}
|
|
EXPORT_SYMBOL_GPL(vhost_vq_init_access);
|
|
|
|
static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
|
|
struct iovec iov[], int iov_size, int access)
|
|
{
|
|
const struct vhost_umem_node *node;
|
|
struct vhost_dev *dev = vq->dev;
|
|
struct vhost_umem *umem = dev->iotlb ? dev->iotlb : dev->umem;
|
|
struct iovec *_iov;
|
|
u64 s = 0;
|
|
int ret = 0;
|
|
|
|
while ((u64)len > s) {
|
|
u64 size;
|
|
if (unlikely(ret >= iov_size)) {
|
|
ret = -ENOBUFS;
|
|
break;
|
|
}
|
|
|
|
node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
|
|
addr, addr + len - 1);
|
|
if (node == NULL || node->start > addr) {
|
|
if (umem != dev->iotlb) {
|
|
ret = -EFAULT;
|
|
break;
|
|
}
|
|
ret = -EAGAIN;
|
|
break;
|
|
} else if (!(node->perm & access)) {
|
|
ret = -EPERM;
|
|
break;
|
|
}
|
|
|
|
_iov = iov + ret;
|
|
size = node->size - addr + node->start;
|
|
_iov->iov_len = min((u64)len - s, size);
|
|
_iov->iov_base = (void __user *)(unsigned long)
|
|
(node->userspace_addr + addr - node->start);
|
|
s += size;
|
|
addr += size;
|
|
++ret;
|
|
}
|
|
|
|
if (ret == -EAGAIN)
|
|
vhost_iotlb_miss(vq, addr, access);
|
|
return ret;
|
|
}
|
|
|
|
/* Each buffer in the virtqueues is actually a chain of descriptors. This
|
|
* function returns the next descriptor in the chain,
|
|
* or -1U if we're at the end. */
|
|
static unsigned next_desc(struct vhost_virtqueue *vq, struct vring_desc *desc)
|
|
{
|
|
unsigned int next;
|
|
|
|
/* If this descriptor says it doesn't chain, we're done. */
|
|
if (!(desc->flags & cpu_to_vhost16(vq, VRING_DESC_F_NEXT)))
|
|
return -1U;
|
|
|
|
/* Check they're not leading us off end of descriptors. */
|
|
next = vhost16_to_cpu(vq, READ_ONCE(desc->next));
|
|
return next;
|
|
}
|
|
|
|
static int get_indirect(struct vhost_virtqueue *vq,
|
|
struct iovec iov[], unsigned int iov_size,
|
|
unsigned int *out_num, unsigned int *in_num,
|
|
struct vhost_log *log, unsigned int *log_num,
|
|
struct vring_desc *indirect)
|
|
{
|
|
struct vring_desc desc;
|
|
unsigned int i = 0, count, found = 0;
|
|
u32 len = vhost32_to_cpu(vq, indirect->len);
|
|
struct iov_iter from;
|
|
int ret, access;
|
|
|
|
/* Sanity check */
|
|
if (unlikely(len % sizeof desc)) {
|
|
vq_err(vq, "Invalid length in indirect descriptor: "
|
|
"len 0x%llx not multiple of 0x%zx\n",
|
|
(unsigned long long)len,
|
|
sizeof desc);
|
|
return -EINVAL;
|
|
}
|
|
|
|
ret = translate_desc(vq, vhost64_to_cpu(vq, indirect->addr), len, vq->indirect,
|
|
UIO_MAXIOV, VHOST_ACCESS_RO);
|
|
if (unlikely(ret < 0)) {
|
|
if (ret != -EAGAIN)
|
|
vq_err(vq, "Translation failure %d in indirect.\n", ret);
|
|
return ret;
|
|
}
|
|
iov_iter_init(&from, READ, vq->indirect, ret, len);
|
|
|
|
/* We will use the result as an address to read from, so most
|
|
* architectures only need a compiler barrier here. */
|
|
read_barrier_depends();
|
|
|
|
count = len / sizeof desc;
|
|
/* Buffers are chained via a 16 bit next field, so
|
|
* we can have at most 2^16 of these. */
|
|
if (unlikely(count > USHRT_MAX + 1)) {
|
|
vq_err(vq, "Indirect buffer length too big: %d\n",
|
|
indirect->len);
|
|
return -E2BIG;
|
|
}
|
|
|
|
do {
|
|
unsigned iov_count = *in_num + *out_num;
|
|
if (unlikely(++found > count)) {
|
|
vq_err(vq, "Loop detected: last one at %u "
|
|
"indirect size %u\n",
|
|
i, count);
|
|
return -EINVAL;
|
|
}
|
|
if (unlikely(!copy_from_iter_full(&desc, sizeof(desc), &from))) {
|
|
vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n",
|
|
i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc);
|
|
return -EINVAL;
|
|
}
|
|
if (unlikely(desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT))) {
|
|
vq_err(vq, "Nested indirect descriptor: idx %d, %zx\n",
|
|
i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc);
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE))
|
|
access = VHOST_ACCESS_WO;
|
|
else
|
|
access = VHOST_ACCESS_RO;
|
|
|
|
ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
|
|
vhost32_to_cpu(vq, desc.len), iov + iov_count,
|
|
iov_size - iov_count, access);
|
|
if (unlikely(ret < 0)) {
|
|
if (ret != -EAGAIN)
|
|
vq_err(vq, "Translation failure %d indirect idx %d\n",
|
|
ret, i);
|
|
return ret;
|
|
}
|
|
/* If this is an input descriptor, increment that count. */
|
|
if (access == VHOST_ACCESS_WO) {
|
|
*in_num += ret;
|
|
if (unlikely(log)) {
|
|
log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
|
|
log[*log_num].len = vhost32_to_cpu(vq, desc.len);
|
|
++*log_num;
|
|
}
|
|
} else {
|
|
/* If it's an output descriptor, they're all supposed
|
|
* to come before any input descriptors. */
|
|
if (unlikely(*in_num)) {
|
|
vq_err(vq, "Indirect descriptor "
|
|
"has out after in: idx %d\n", i);
|
|
return -EINVAL;
|
|
}
|
|
*out_num += ret;
|
|
}
|
|
} while ((i = next_desc(vq, &desc)) != -1);
|
|
return 0;
|
|
}
|
|
|
|
/* This looks in the virtqueue and for the first available buffer, and converts
|
|
* it to an iovec for convenient access. Since descriptors consist of some
|
|
* number of output then some number of input descriptors, it's actually two
|
|
* iovecs, but we pack them into one and note how many of each there were.
|
|
*
|
|
* This function returns the descriptor number found, or vq->num (which is
|
|
* never a valid descriptor number) if none was found. A negative code is
|
|
* returned on error. */
|
|
int vhost_get_vq_desc(struct vhost_virtqueue *vq,
|
|
struct iovec iov[], unsigned int iov_size,
|
|
unsigned int *out_num, unsigned int *in_num,
|
|
struct vhost_log *log, unsigned int *log_num)
|
|
{
|
|
struct vring_desc desc;
|
|
unsigned int i, head, found = 0;
|
|
u16 last_avail_idx;
|
|
__virtio16 avail_idx;
|
|
__virtio16 ring_head;
|
|
int ret, access;
|
|
|
|
/* Check it isn't doing very strange things with descriptor numbers. */
|
|
last_avail_idx = vq->last_avail_idx;
|
|
|
|
if (vq->avail_idx == vq->last_avail_idx) {
|
|
if (unlikely(vhost_get_avail(vq, avail_idx, &vq->avail->idx))) {
|
|
vq_err(vq, "Failed to access avail idx at %p\n",
|
|
&vq->avail->idx);
|
|
return -EFAULT;
|
|
}
|
|
vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
|
|
|
|
if (unlikely((u16)(vq->avail_idx - last_avail_idx) > vq->num)) {
|
|
vq_err(vq, "Guest moved used index from %u to %u",
|
|
last_avail_idx, vq->avail_idx);
|
|
return -EFAULT;
|
|
}
|
|
|
|
/* If there's nothing new since last we looked, return
|
|
* invalid.
|
|
*/
|
|
if (vq->avail_idx == last_avail_idx)
|
|
return vq->num;
|
|
|
|
/* Only get avail ring entries after they have been
|
|
* exposed by guest.
|
|
*/
|
|
smp_rmb();
|
|
}
|
|
|
|
/* Grab the next descriptor number they're advertising, and increment
|
|
* the index we've seen. */
|
|
if (unlikely(vhost_get_avail(vq, ring_head,
|
|
&vq->avail->ring[last_avail_idx & (vq->num - 1)]))) {
|
|
vq_err(vq, "Failed to read head: idx %d address %p\n",
|
|
last_avail_idx,
|
|
&vq->avail->ring[last_avail_idx % vq->num]);
|
|
return -EFAULT;
|
|
}
|
|
|
|
head = vhost16_to_cpu(vq, ring_head);
|
|
|
|
/* If their number is silly, that's an error. */
|
|
if (unlikely(head >= vq->num)) {
|
|
vq_err(vq, "Guest says index %u > %u is available",
|
|
head, vq->num);
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* When we start there are none of either input nor output. */
|
|
*out_num = *in_num = 0;
|
|
if (unlikely(log))
|
|
*log_num = 0;
|
|
|
|
i = head;
|
|
do {
|
|
unsigned iov_count = *in_num + *out_num;
|
|
if (unlikely(i >= vq->num)) {
|
|
vq_err(vq, "Desc index is %u > %u, head = %u",
|
|
i, vq->num, head);
|
|
return -EINVAL;
|
|
}
|
|
if (unlikely(++found > vq->num)) {
|
|
vq_err(vq, "Loop detected: last one at %u "
|
|
"vq size %u head %u\n",
|
|
i, vq->num, head);
|
|
return -EINVAL;
|
|
}
|
|
ret = vhost_copy_from_user(vq, &desc, vq->desc + i,
|
|
sizeof desc);
|
|
if (unlikely(ret)) {
|
|
vq_err(vq, "Failed to get descriptor: idx %d addr %p\n",
|
|
i, vq->desc + i);
|
|
return -EFAULT;
|
|
}
|
|
if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT)) {
|
|
ret = get_indirect(vq, iov, iov_size,
|
|
out_num, in_num,
|
|
log, log_num, &desc);
|
|
if (unlikely(ret < 0)) {
|
|
if (ret != -EAGAIN)
|
|
vq_err(vq, "Failure detected "
|
|
"in indirect descriptor at idx %d\n", i);
|
|
return ret;
|
|
}
|
|
continue;
|
|
}
|
|
|
|
if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE))
|
|
access = VHOST_ACCESS_WO;
|
|
else
|
|
access = VHOST_ACCESS_RO;
|
|
ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
|
|
vhost32_to_cpu(vq, desc.len), iov + iov_count,
|
|
iov_size - iov_count, access);
|
|
if (unlikely(ret < 0)) {
|
|
if (ret != -EAGAIN)
|
|
vq_err(vq, "Translation failure %d descriptor idx %d\n",
|
|
ret, i);
|
|
return ret;
|
|
}
|
|
if (access == VHOST_ACCESS_WO) {
|
|
/* If this is an input descriptor,
|
|
* increment that count. */
|
|
*in_num += ret;
|
|
if (unlikely(log)) {
|
|
log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
|
|
log[*log_num].len = vhost32_to_cpu(vq, desc.len);
|
|
++*log_num;
|
|
}
|
|
} else {
|
|
/* If it's an output descriptor, they're all supposed
|
|
* to come before any input descriptors. */
|
|
if (unlikely(*in_num)) {
|
|
vq_err(vq, "Descriptor has out after in: "
|
|
"idx %d\n", i);
|
|
return -EINVAL;
|
|
}
|
|
*out_num += ret;
|
|
}
|
|
} while ((i = next_desc(vq, &desc)) != -1);
|
|
|
|
/* On success, increment avail index. */
|
|
vq->last_avail_idx++;
|
|
|
|
/* Assume notifications from guest are disabled at this point,
|
|
* if they aren't we would need to update avail_event index. */
|
|
BUG_ON(!(vq->used_flags & VRING_USED_F_NO_NOTIFY));
|
|
return head;
|
|
}
|
|
EXPORT_SYMBOL_GPL(vhost_get_vq_desc);
|
|
|
|
/* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */
|
|
void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n)
|
|
{
|
|
vq->last_avail_idx -= n;
|
|
}
|
|
EXPORT_SYMBOL_GPL(vhost_discard_vq_desc);
|
|
|
|
/* After we've used one of their buffers, we tell them about it. We'll then
|
|
* want to notify the guest, using eventfd. */
|
|
int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len)
|
|
{
|
|
struct vring_used_elem heads = {
|
|
cpu_to_vhost32(vq, head),
|
|
cpu_to_vhost32(vq, len)
|
|
};
|
|
|
|
return vhost_add_used_n(vq, &heads, 1);
|
|
}
|
|
EXPORT_SYMBOL_GPL(vhost_add_used);
|
|
|
|
static int __vhost_add_used_n(struct vhost_virtqueue *vq,
|
|
struct vring_used_elem *heads,
|
|
unsigned count)
|
|
{
|
|
struct vring_used_elem __user *used;
|
|
u16 old, new;
|
|
int start;
|
|
|
|
start = vq->last_used_idx & (vq->num - 1);
|
|
used = vq->used->ring + start;
|
|
if (count == 1) {
|
|
if (vhost_put_user(vq, heads[0].id, &used->id)) {
|
|
vq_err(vq, "Failed to write used id");
|
|
return -EFAULT;
|
|
}
|
|
if (vhost_put_user(vq, heads[0].len, &used->len)) {
|
|
vq_err(vq, "Failed to write used len");
|
|
return -EFAULT;
|
|
}
|
|
} else if (vhost_copy_to_user(vq, used, heads, count * sizeof *used)) {
|
|
vq_err(vq, "Failed to write used");
|
|
return -EFAULT;
|
|
}
|
|
if (unlikely(vq->log_used)) {
|
|
/* Make sure data is seen before log. */
|
|
smp_wmb();
|
|
/* Log used ring entry write. */
|
|
log_write(vq->log_base,
|
|
vq->log_addr +
|
|
((void __user *)used - (void __user *)vq->used),
|
|
count * sizeof *used);
|
|
}
|
|
old = vq->last_used_idx;
|
|
new = (vq->last_used_idx += count);
|
|
/* If the driver never bothers to signal in a very long while,
|
|
* used index might wrap around. If that happens, invalidate
|
|
* signalled_used index we stored. TODO: make sure driver
|
|
* signals at least once in 2^16 and remove this. */
|
|
if (unlikely((u16)(new - vq->signalled_used) < (u16)(new - old)))
|
|
vq->signalled_used_valid = false;
|
|
return 0;
|
|
}
|
|
|
|
/* After we've used one of their buffers, we tell them about it. We'll then
|
|
* want to notify the guest, using eventfd. */
|
|
int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
|
|
unsigned count)
|
|
{
|
|
int start, n, r;
|
|
|
|
start = vq->last_used_idx & (vq->num - 1);
|
|
n = vq->num - start;
|
|
if (n < count) {
|
|
r = __vhost_add_used_n(vq, heads, n);
|
|
if (r < 0)
|
|
return r;
|
|
heads += n;
|
|
count -= n;
|
|
}
|
|
r = __vhost_add_used_n(vq, heads, count);
|
|
|
|
/* Make sure buffer is written before we update index. */
|
|
smp_wmb();
|
|
if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->last_used_idx),
|
|
&vq->used->idx)) {
|
|
vq_err(vq, "Failed to increment used idx");
|
|
return -EFAULT;
|
|
}
|
|
if (unlikely(vq->log_used)) {
|
|
/* Log used index update. */
|
|
log_write(vq->log_base,
|
|
vq->log_addr + offsetof(struct vring_used, idx),
|
|
sizeof vq->used->idx);
|
|
if (vq->log_ctx)
|
|
eventfd_signal(vq->log_ctx, 1);
|
|
}
|
|
return r;
|
|
}
|
|
EXPORT_SYMBOL_GPL(vhost_add_used_n);
|
|
|
|
static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
|
|
{
|
|
__u16 old, new;
|
|
__virtio16 event;
|
|
bool v;
|
|
/* Flush out used index updates. This is paired
|
|
* with the barrier that the Guest executes when enabling
|
|
* interrupts. */
|
|
smp_mb();
|
|
|
|
if (vhost_has_feature(vq, VIRTIO_F_NOTIFY_ON_EMPTY) &&
|
|
unlikely(vq->avail_idx == vq->last_avail_idx))
|
|
return true;
|
|
|
|
if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
|
|
__virtio16 flags;
|
|
if (vhost_get_avail(vq, flags, &vq->avail->flags)) {
|
|
vq_err(vq, "Failed to get flags");
|
|
return true;
|
|
}
|
|
return !(flags & cpu_to_vhost16(vq, VRING_AVAIL_F_NO_INTERRUPT));
|
|
}
|
|
old = vq->signalled_used;
|
|
v = vq->signalled_used_valid;
|
|
new = vq->signalled_used = vq->last_used_idx;
|
|
vq->signalled_used_valid = true;
|
|
|
|
if (unlikely(!v))
|
|
return true;
|
|
|
|
if (vhost_get_avail(vq, event, vhost_used_event(vq))) {
|
|
vq_err(vq, "Failed to get used event idx");
|
|
return true;
|
|
}
|
|
return vring_need_event(vhost16_to_cpu(vq, event), new, old);
|
|
}
|
|
|
|
/* This actually signals the guest, using eventfd. */
|
|
void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq)
|
|
{
|
|
/* Signal the Guest tell them we used something up. */
|
|
if (vq->call_ctx && vhost_notify(dev, vq))
|
|
eventfd_signal(vq->call_ctx, 1);
|
|
}
|
|
EXPORT_SYMBOL_GPL(vhost_signal);
|
|
|
|
/* And here's the combo meal deal. Supersize me! */
|
|
void vhost_add_used_and_signal(struct vhost_dev *dev,
|
|
struct vhost_virtqueue *vq,
|
|
unsigned int head, int len)
|
|
{
|
|
vhost_add_used(vq, head, len);
|
|
vhost_signal(dev, vq);
|
|
}
|
|
EXPORT_SYMBOL_GPL(vhost_add_used_and_signal);
|
|
|
|
/* multi-buffer version of vhost_add_used_and_signal */
|
|
void vhost_add_used_and_signal_n(struct vhost_dev *dev,
|
|
struct vhost_virtqueue *vq,
|
|
struct vring_used_elem *heads, unsigned count)
|
|
{
|
|
vhost_add_used_n(vq, heads, count);
|
|
vhost_signal(dev, vq);
|
|
}
|
|
EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n);
|
|
|
|
/* return true if we're sure that avaiable ring is empty */
|
|
bool vhost_vq_avail_empty(struct vhost_dev *dev, struct vhost_virtqueue *vq)
|
|
{
|
|
__virtio16 avail_idx;
|
|
int r;
|
|
|
|
if (vq->avail_idx != vq->last_avail_idx)
|
|
return false;
|
|
|
|
r = vhost_get_avail(vq, avail_idx, &vq->avail->idx);
|
|
if (unlikely(r))
|
|
return false;
|
|
vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
|
|
|
|
return vq->avail_idx == vq->last_avail_idx;
|
|
}
|
|
EXPORT_SYMBOL_GPL(vhost_vq_avail_empty);
|
|
|
|
/* OK, now we need to know about added descriptors. */
|
|
bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
|
|
{
|
|
__virtio16 avail_idx;
|
|
int r;
|
|
|
|
if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY))
|
|
return false;
|
|
vq->used_flags &= ~VRING_USED_F_NO_NOTIFY;
|
|
if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
|
|
r = vhost_update_used_flags(vq);
|
|
if (r) {
|
|
vq_err(vq, "Failed to enable notification at %p: %d\n",
|
|
&vq->used->flags, r);
|
|
return false;
|
|
}
|
|
} else {
|
|
r = vhost_update_avail_event(vq, vq->avail_idx);
|
|
if (r) {
|
|
vq_err(vq, "Failed to update avail event index at %p: %d\n",
|
|
vhost_avail_event(vq), r);
|
|
return false;
|
|
}
|
|
}
|
|
/* They could have slipped one in as we were doing that: make
|
|
* sure it's written, then check again. */
|
|
smp_mb();
|
|
r = vhost_get_avail(vq, avail_idx, &vq->avail->idx);
|
|
if (r) {
|
|
vq_err(vq, "Failed to check avail idx at %p: %d\n",
|
|
&vq->avail->idx, r);
|
|
return false;
|
|
}
|
|
|
|
return vhost16_to_cpu(vq, avail_idx) != vq->avail_idx;
|
|
}
|
|
EXPORT_SYMBOL_GPL(vhost_enable_notify);
|
|
|
|
/* We don't need to be notified again. */
|
|
void vhost_disable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
|
|
{
|
|
int r;
|
|
|
|
if (vq->used_flags & VRING_USED_F_NO_NOTIFY)
|
|
return;
|
|
vq->used_flags |= VRING_USED_F_NO_NOTIFY;
|
|
if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
|
|
r = vhost_update_used_flags(vq);
|
|
if (r)
|
|
vq_err(vq, "Failed to enable notification at %p: %d\n",
|
|
&vq->used->flags, r);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(vhost_disable_notify);
|
|
|
|
/* Create a new message. */
|
|
struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type)
|
|
{
|
|
struct vhost_msg_node *node = kmalloc(sizeof *node, GFP_KERNEL);
|
|
if (!node)
|
|
return NULL;
|
|
|
|
/* Make sure all padding within the structure is initialized. */
|
|
memset(&node->msg, 0, sizeof node->msg);
|
|
node->vq = vq;
|
|
node->msg.type = type;
|
|
return node;
|
|
}
|
|
EXPORT_SYMBOL_GPL(vhost_new_msg);
|
|
|
|
void vhost_enqueue_msg(struct vhost_dev *dev, struct list_head *head,
|
|
struct vhost_msg_node *node)
|
|
{
|
|
spin_lock(&dev->iotlb_lock);
|
|
list_add_tail(&node->node, head);
|
|
spin_unlock(&dev->iotlb_lock);
|
|
|
|
wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM);
|
|
}
|
|
EXPORT_SYMBOL_GPL(vhost_enqueue_msg);
|
|
|
|
struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
|
|
struct list_head *head)
|
|
{
|
|
struct vhost_msg_node *node = NULL;
|
|
|
|
spin_lock(&dev->iotlb_lock);
|
|
if (!list_empty(head)) {
|
|
node = list_first_entry(head, struct vhost_msg_node,
|
|
node);
|
|
list_del(&node->node);
|
|
}
|
|
spin_unlock(&dev->iotlb_lock);
|
|
|
|
return node;
|
|
}
|
|
EXPORT_SYMBOL_GPL(vhost_dequeue_msg);
|
|
|
|
|
|
static int __init vhost_init(void)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static void __exit vhost_exit(void)
|
|
{
|
|
}
|
|
|
|
module_init(vhost_init);
|
|
module_exit(vhost_exit);
|
|
|
|
MODULE_VERSION("0.0.1");
|
|
MODULE_LICENSE("GPL v2");
|
|
MODULE_AUTHOR("Michael S. Tsirkin");
|
|
MODULE_DESCRIPTION("Host kernel accelerator for virtio");
|