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![Andrea Parri (Microsoft)](/assets/img/avatar_default.png)
Use blk_mq_unique_tag() to generate requestIDs for StorVSC, avoiding all issues with allocating enough entries in the VMbus requestor. Suggested-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Acked-by: Martin K. Petersen <martin.petersen@oracle.com> Link: https://lore.kernel.org/r/20210510210841.370472-1-parri.andrea@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
1272 lines
36 KiB
C
1272 lines
36 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (c) 2009, Microsoft Corporation.
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*
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* Authors:
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* Haiyang Zhang <haiyangz@microsoft.com>
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* Hank Janssen <hjanssen@microsoft.com>
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/wait.h>
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <linux/hyperv.h>
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#include <linux/uio.h>
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#include <linux/interrupt.h>
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#include <asm/page.h>
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#include <asm/mshyperv.h>
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#include "hyperv_vmbus.h"
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/*
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* hv_gpadl_size - Return the real size of a gpadl, the size that Hyper-V uses
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*
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* For BUFFER gpadl, Hyper-V uses the exact same size as the guest does.
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*
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* For RING gpadl, in each ring, the guest uses one PAGE_SIZE as the header
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* (because of the alignment requirement), however, the hypervisor only
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* uses the first HV_HYP_PAGE_SIZE as the header, therefore leaving a
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* (PAGE_SIZE - HV_HYP_PAGE_SIZE) gap. And since there are two rings in a
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* ringbuffer, the total size for a RING gpadl that Hyper-V uses is the
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* total size that the guest uses minus twice of the gap size.
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*/
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static inline u32 hv_gpadl_size(enum hv_gpadl_type type, u32 size)
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{
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switch (type) {
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case HV_GPADL_BUFFER:
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return size;
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case HV_GPADL_RING:
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/* The size of a ringbuffer must be page-aligned */
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BUG_ON(size % PAGE_SIZE);
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/*
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* Two things to notice here:
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* 1) We're processing two ring buffers as a unit
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* 2) We're skipping any space larger than HV_HYP_PAGE_SIZE in
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* the first guest-size page of each of the two ring buffers.
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* So we effectively subtract out two guest-size pages, and add
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* back two Hyper-V size pages.
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*/
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return size - 2 * (PAGE_SIZE - HV_HYP_PAGE_SIZE);
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}
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BUG();
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return 0;
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}
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/*
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* hv_ring_gpadl_send_hvpgoffset - Calculate the send offset (in unit of
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* HV_HYP_PAGE) in a ring gpadl based on the
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* offset in the guest
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*
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* @offset: the offset (in bytes) where the send ringbuffer starts in the
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* virtual address space of the guest
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*/
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static inline u32 hv_ring_gpadl_send_hvpgoffset(u32 offset)
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{
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/*
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* For RING gpadl, in each ring, the guest uses one PAGE_SIZE as the
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* header (because of the alignment requirement), however, the
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* hypervisor only uses the first HV_HYP_PAGE_SIZE as the header,
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* therefore leaving a (PAGE_SIZE - HV_HYP_PAGE_SIZE) gap.
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*
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* And to calculate the effective send offset in gpadl, we need to
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* substract this gap.
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*/
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return (offset - (PAGE_SIZE - HV_HYP_PAGE_SIZE)) >> HV_HYP_PAGE_SHIFT;
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}
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/*
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* hv_gpadl_hvpfn - Return the Hyper-V page PFN of the @i th Hyper-V page in
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* the gpadl
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*
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* @type: the type of the gpadl
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* @kbuffer: the pointer to the gpadl in the guest
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* @size: the total size (in bytes) of the gpadl
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* @send_offset: the offset (in bytes) where the send ringbuffer starts in the
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* virtual address space of the guest
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* @i: the index
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*/
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static inline u64 hv_gpadl_hvpfn(enum hv_gpadl_type type, void *kbuffer,
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u32 size, u32 send_offset, int i)
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{
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int send_idx = hv_ring_gpadl_send_hvpgoffset(send_offset);
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unsigned long delta = 0UL;
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switch (type) {
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case HV_GPADL_BUFFER:
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break;
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case HV_GPADL_RING:
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if (i == 0)
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delta = 0;
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else if (i <= send_idx)
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delta = PAGE_SIZE - HV_HYP_PAGE_SIZE;
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else
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delta = 2 * (PAGE_SIZE - HV_HYP_PAGE_SIZE);
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break;
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default:
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BUG();
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break;
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}
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return virt_to_hvpfn(kbuffer + delta + (HV_HYP_PAGE_SIZE * i));
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}
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/*
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* vmbus_setevent- Trigger an event notification on the specified
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* channel.
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*/
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void vmbus_setevent(struct vmbus_channel *channel)
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{
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struct hv_monitor_page *monitorpage;
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trace_vmbus_setevent(channel);
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/*
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* For channels marked as in "low latency" mode
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* bypass the monitor page mechanism.
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*/
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if (channel->offermsg.monitor_allocated && !channel->low_latency) {
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vmbus_send_interrupt(channel->offermsg.child_relid);
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/* Get the child to parent monitor page */
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monitorpage = vmbus_connection.monitor_pages[1];
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sync_set_bit(channel->monitor_bit,
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(unsigned long *)&monitorpage->trigger_group
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[channel->monitor_grp].pending);
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} else {
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vmbus_set_event(channel);
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}
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}
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EXPORT_SYMBOL_GPL(vmbus_setevent);
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/* vmbus_free_ring - drop mapping of ring buffer */
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void vmbus_free_ring(struct vmbus_channel *channel)
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{
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hv_ringbuffer_cleanup(&channel->outbound);
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hv_ringbuffer_cleanup(&channel->inbound);
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if (channel->ringbuffer_page) {
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__free_pages(channel->ringbuffer_page,
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get_order(channel->ringbuffer_pagecount
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<< PAGE_SHIFT));
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channel->ringbuffer_page = NULL;
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}
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}
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EXPORT_SYMBOL_GPL(vmbus_free_ring);
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/* vmbus_alloc_ring - allocate and map pages for ring buffer */
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int vmbus_alloc_ring(struct vmbus_channel *newchannel,
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u32 send_size, u32 recv_size)
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{
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struct page *page;
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int order;
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if (send_size % PAGE_SIZE || recv_size % PAGE_SIZE)
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return -EINVAL;
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/* Allocate the ring buffer */
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order = get_order(send_size + recv_size);
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page = alloc_pages_node(cpu_to_node(newchannel->target_cpu),
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GFP_KERNEL|__GFP_ZERO, order);
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if (!page)
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page = alloc_pages(GFP_KERNEL|__GFP_ZERO, order);
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if (!page)
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return -ENOMEM;
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newchannel->ringbuffer_page = page;
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newchannel->ringbuffer_pagecount = (send_size + recv_size) >> PAGE_SHIFT;
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newchannel->ringbuffer_send_offset = send_size >> PAGE_SHIFT;
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return 0;
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}
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EXPORT_SYMBOL_GPL(vmbus_alloc_ring);
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/* Used for Hyper-V Socket: a guest client's connect() to the host */
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int vmbus_send_tl_connect_request(const guid_t *shv_guest_servie_id,
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const guid_t *shv_host_servie_id)
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{
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struct vmbus_channel_tl_connect_request conn_msg;
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int ret;
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memset(&conn_msg, 0, sizeof(conn_msg));
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conn_msg.header.msgtype = CHANNELMSG_TL_CONNECT_REQUEST;
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conn_msg.guest_endpoint_id = *shv_guest_servie_id;
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conn_msg.host_service_id = *shv_host_servie_id;
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ret = vmbus_post_msg(&conn_msg, sizeof(conn_msg), true);
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trace_vmbus_send_tl_connect_request(&conn_msg, ret);
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return ret;
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}
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EXPORT_SYMBOL_GPL(vmbus_send_tl_connect_request);
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static int send_modifychannel_without_ack(struct vmbus_channel *channel, u32 target_vp)
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{
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struct vmbus_channel_modifychannel msg;
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int ret;
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memset(&msg, 0, sizeof(msg));
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msg.header.msgtype = CHANNELMSG_MODIFYCHANNEL;
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msg.child_relid = channel->offermsg.child_relid;
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msg.target_vp = target_vp;
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ret = vmbus_post_msg(&msg, sizeof(msg), true);
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trace_vmbus_send_modifychannel(&msg, ret);
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return ret;
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}
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static int send_modifychannel_with_ack(struct vmbus_channel *channel, u32 target_vp)
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{
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struct vmbus_channel_modifychannel *msg;
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struct vmbus_channel_msginfo *info;
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unsigned long flags;
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int ret;
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info = kzalloc(sizeof(struct vmbus_channel_msginfo) +
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sizeof(struct vmbus_channel_modifychannel),
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GFP_KERNEL);
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if (!info)
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return -ENOMEM;
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init_completion(&info->waitevent);
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info->waiting_channel = channel;
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msg = (struct vmbus_channel_modifychannel *)info->msg;
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msg->header.msgtype = CHANNELMSG_MODIFYCHANNEL;
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msg->child_relid = channel->offermsg.child_relid;
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msg->target_vp = target_vp;
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spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
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list_add_tail(&info->msglistentry, &vmbus_connection.chn_msg_list);
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spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
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ret = vmbus_post_msg(msg, sizeof(*msg), true);
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trace_vmbus_send_modifychannel(msg, ret);
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if (ret != 0) {
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spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
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list_del(&info->msglistentry);
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spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
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goto free_info;
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}
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/*
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* Release channel_mutex; otherwise, vmbus_onoffer_rescind() could block on
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* the mutex and be unable to signal the completion.
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*
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* See the caller target_cpu_store() for information about the usage of the
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* mutex.
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*/
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mutex_unlock(&vmbus_connection.channel_mutex);
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wait_for_completion(&info->waitevent);
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mutex_lock(&vmbus_connection.channel_mutex);
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spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
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list_del(&info->msglistentry);
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spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
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if (info->response.modify_response.status)
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ret = -EAGAIN;
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free_info:
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kfree(info);
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return ret;
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}
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/*
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* Set/change the vCPU (@target_vp) the channel (@child_relid) will interrupt.
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*
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* CHANNELMSG_MODIFYCHANNEL messages are aynchronous. When VMbus version 5.3
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* or later is negotiated, Hyper-V always sends an ACK in response to such a
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* message. For VMbus version 5.2 and earlier, it never sends an ACK. With-
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* out an ACK, we can not know when the host will stop interrupting the "old"
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* vCPU and start interrupting the "new" vCPU for the given channel.
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*
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* The CHANNELMSG_MODIFYCHANNEL message type is supported since VMBus version
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* VERSION_WIN10_V4_1.
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*/
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int vmbus_send_modifychannel(struct vmbus_channel *channel, u32 target_vp)
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{
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if (vmbus_proto_version >= VERSION_WIN10_V5_3)
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return send_modifychannel_with_ack(channel, target_vp);
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return send_modifychannel_without_ack(channel, target_vp);
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}
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EXPORT_SYMBOL_GPL(vmbus_send_modifychannel);
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/*
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* create_gpadl_header - Creates a gpadl for the specified buffer
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*/
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static int create_gpadl_header(enum hv_gpadl_type type, void *kbuffer,
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u32 size, u32 send_offset,
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struct vmbus_channel_msginfo **msginfo)
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{
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int i;
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int pagecount;
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struct vmbus_channel_gpadl_header *gpadl_header;
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struct vmbus_channel_gpadl_body *gpadl_body;
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struct vmbus_channel_msginfo *msgheader;
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struct vmbus_channel_msginfo *msgbody = NULL;
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u32 msgsize;
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int pfnsum, pfncount, pfnleft, pfncurr, pfnsize;
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pagecount = hv_gpadl_size(type, size) >> HV_HYP_PAGE_SHIFT;
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/* do we need a gpadl body msg */
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pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
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sizeof(struct vmbus_channel_gpadl_header) -
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sizeof(struct gpa_range);
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pfncount = pfnsize / sizeof(u64);
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if (pagecount > pfncount) {
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/* we need a gpadl body */
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/* fill in the header */
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msgsize = sizeof(struct vmbus_channel_msginfo) +
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sizeof(struct vmbus_channel_gpadl_header) +
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sizeof(struct gpa_range) + pfncount * sizeof(u64);
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msgheader = kzalloc(msgsize, GFP_KERNEL);
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if (!msgheader)
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goto nomem;
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INIT_LIST_HEAD(&msgheader->submsglist);
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msgheader->msgsize = msgsize;
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gpadl_header = (struct vmbus_channel_gpadl_header *)
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msgheader->msg;
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gpadl_header->rangecount = 1;
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gpadl_header->range_buflen = sizeof(struct gpa_range) +
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pagecount * sizeof(u64);
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gpadl_header->range[0].byte_offset = 0;
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gpadl_header->range[0].byte_count = hv_gpadl_size(type, size);
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for (i = 0; i < pfncount; i++)
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gpadl_header->range[0].pfn_array[i] = hv_gpadl_hvpfn(
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type, kbuffer, size, send_offset, i);
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*msginfo = msgheader;
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pfnsum = pfncount;
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pfnleft = pagecount - pfncount;
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/* how many pfns can we fit */
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pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
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sizeof(struct vmbus_channel_gpadl_body);
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pfncount = pfnsize / sizeof(u64);
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/* fill in the body */
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while (pfnleft) {
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if (pfnleft > pfncount)
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pfncurr = pfncount;
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else
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pfncurr = pfnleft;
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msgsize = sizeof(struct vmbus_channel_msginfo) +
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sizeof(struct vmbus_channel_gpadl_body) +
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pfncurr * sizeof(u64);
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msgbody = kzalloc(msgsize, GFP_KERNEL);
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if (!msgbody) {
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struct vmbus_channel_msginfo *pos = NULL;
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struct vmbus_channel_msginfo *tmp = NULL;
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/*
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* Free up all the allocated messages.
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*/
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list_for_each_entry_safe(pos, tmp,
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&msgheader->submsglist,
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msglistentry) {
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list_del(&pos->msglistentry);
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kfree(pos);
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}
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goto nomem;
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}
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msgbody->msgsize = msgsize;
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gpadl_body =
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(struct vmbus_channel_gpadl_body *)msgbody->msg;
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/*
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* Gpadl is u32 and we are using a pointer which could
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* be 64-bit
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* This is governed by the guest/host protocol and
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* so the hypervisor guarantees that this is ok.
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*/
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for (i = 0; i < pfncurr; i++)
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gpadl_body->pfn[i] = hv_gpadl_hvpfn(type,
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kbuffer, size, send_offset, pfnsum + i);
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/* add to msg header */
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list_add_tail(&msgbody->msglistentry,
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&msgheader->submsglist);
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pfnsum += pfncurr;
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pfnleft -= pfncurr;
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}
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} else {
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/* everything fits in a header */
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msgsize = sizeof(struct vmbus_channel_msginfo) +
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sizeof(struct vmbus_channel_gpadl_header) +
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sizeof(struct gpa_range) + pagecount * sizeof(u64);
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msgheader = kzalloc(msgsize, GFP_KERNEL);
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if (msgheader == NULL)
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goto nomem;
|
|
|
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INIT_LIST_HEAD(&msgheader->submsglist);
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msgheader->msgsize = msgsize;
|
|
|
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gpadl_header = (struct vmbus_channel_gpadl_header *)
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msgheader->msg;
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gpadl_header->rangecount = 1;
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gpadl_header->range_buflen = sizeof(struct gpa_range) +
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pagecount * sizeof(u64);
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gpadl_header->range[0].byte_offset = 0;
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gpadl_header->range[0].byte_count = hv_gpadl_size(type, size);
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for (i = 0; i < pagecount; i++)
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gpadl_header->range[0].pfn_array[i] = hv_gpadl_hvpfn(
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type, kbuffer, size, send_offset, i);
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|
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*msginfo = msgheader;
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}
|
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return 0;
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nomem:
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kfree(msgheader);
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kfree(msgbody);
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return -ENOMEM;
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}
|
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|
|
/*
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* __vmbus_establish_gpadl - Establish a GPADL for a buffer or ringbuffer
|
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*
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* @channel: a channel
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* @type: the type of the corresponding GPADL, only meaningful for the guest.
|
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* @kbuffer: from kmalloc or vmalloc
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* @size: page-size multiple
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* @send_offset: the offset (in bytes) where the send ring buffer starts,
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* should be 0 for BUFFER type gpadl
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* @gpadl_handle: some funky thing
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*/
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static int __vmbus_establish_gpadl(struct vmbus_channel *channel,
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enum hv_gpadl_type type, void *kbuffer,
|
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u32 size, u32 send_offset,
|
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u32 *gpadl_handle)
|
|
{
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|
struct vmbus_channel_gpadl_header *gpadlmsg;
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struct vmbus_channel_gpadl_body *gpadl_body;
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struct vmbus_channel_msginfo *msginfo = NULL;
|
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struct vmbus_channel_msginfo *submsginfo, *tmp;
|
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struct list_head *curr;
|
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u32 next_gpadl_handle;
|
|
unsigned long flags;
|
|
int ret = 0;
|
|
|
|
next_gpadl_handle =
|
|
(atomic_inc_return(&vmbus_connection.next_gpadl_handle) - 1);
|
|
|
|
ret = create_gpadl_header(type, kbuffer, size, send_offset, &msginfo);
|
|
if (ret)
|
|
return ret;
|
|
|
|
init_completion(&msginfo->waitevent);
|
|
msginfo->waiting_channel = channel;
|
|
|
|
gpadlmsg = (struct vmbus_channel_gpadl_header *)msginfo->msg;
|
|
gpadlmsg->header.msgtype = CHANNELMSG_GPADL_HEADER;
|
|
gpadlmsg->child_relid = channel->offermsg.child_relid;
|
|
gpadlmsg->gpadl = next_gpadl_handle;
|
|
|
|
|
|
spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
|
|
list_add_tail(&msginfo->msglistentry,
|
|
&vmbus_connection.chn_msg_list);
|
|
|
|
spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
|
|
|
|
if (channel->rescind) {
|
|
ret = -ENODEV;
|
|
goto cleanup;
|
|
}
|
|
|
|
ret = vmbus_post_msg(gpadlmsg, msginfo->msgsize -
|
|
sizeof(*msginfo), true);
|
|
|
|
trace_vmbus_establish_gpadl_header(gpadlmsg, ret);
|
|
|
|
if (ret != 0)
|
|
goto cleanup;
|
|
|
|
list_for_each(curr, &msginfo->submsglist) {
|
|
submsginfo = (struct vmbus_channel_msginfo *)curr;
|
|
gpadl_body =
|
|
(struct vmbus_channel_gpadl_body *)submsginfo->msg;
|
|
|
|
gpadl_body->header.msgtype =
|
|
CHANNELMSG_GPADL_BODY;
|
|
gpadl_body->gpadl = next_gpadl_handle;
|
|
|
|
ret = vmbus_post_msg(gpadl_body,
|
|
submsginfo->msgsize - sizeof(*submsginfo),
|
|
true);
|
|
|
|
trace_vmbus_establish_gpadl_body(gpadl_body, ret);
|
|
|
|
if (ret != 0)
|
|
goto cleanup;
|
|
|
|
}
|
|
wait_for_completion(&msginfo->waitevent);
|
|
|
|
if (msginfo->response.gpadl_created.creation_status != 0) {
|
|
pr_err("Failed to establish GPADL: err = 0x%x\n",
|
|
msginfo->response.gpadl_created.creation_status);
|
|
|
|
ret = -EDQUOT;
|
|
goto cleanup;
|
|
}
|
|
|
|
if (channel->rescind) {
|
|
ret = -ENODEV;
|
|
goto cleanup;
|
|
}
|
|
|
|
/* At this point, we received the gpadl created msg */
|
|
*gpadl_handle = gpadlmsg->gpadl;
|
|
|
|
cleanup:
|
|
spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
|
|
list_del(&msginfo->msglistentry);
|
|
spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
|
|
list_for_each_entry_safe(submsginfo, tmp, &msginfo->submsglist,
|
|
msglistentry) {
|
|
kfree(submsginfo);
|
|
}
|
|
|
|
kfree(msginfo);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* vmbus_establish_gpadl - Establish a GPADL for the specified buffer
|
|
*
|
|
* @channel: a channel
|
|
* @kbuffer: from kmalloc or vmalloc
|
|
* @size: page-size multiple
|
|
* @gpadl_handle: some funky thing
|
|
*/
|
|
int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
|
|
u32 size, u32 *gpadl_handle)
|
|
{
|
|
return __vmbus_establish_gpadl(channel, HV_GPADL_BUFFER, kbuffer, size,
|
|
0U, gpadl_handle);
|
|
}
|
|
EXPORT_SYMBOL_GPL(vmbus_establish_gpadl);
|
|
|
|
/**
|
|
* request_arr_init - Allocates memory for the requestor array. Each slot
|
|
* keeps track of the next available slot in the array. Initially, each
|
|
* slot points to the next one (as in a Linked List). The last slot
|
|
* does not point to anything, so its value is U64_MAX by default.
|
|
* @size The size of the array
|
|
*/
|
|
static u64 *request_arr_init(u32 size)
|
|
{
|
|
int i;
|
|
u64 *req_arr;
|
|
|
|
req_arr = kcalloc(size, sizeof(u64), GFP_KERNEL);
|
|
if (!req_arr)
|
|
return NULL;
|
|
|
|
for (i = 0; i < size - 1; i++)
|
|
req_arr[i] = i + 1;
|
|
|
|
/* Last slot (no more available slots) */
|
|
req_arr[i] = U64_MAX;
|
|
|
|
return req_arr;
|
|
}
|
|
|
|
/*
|
|
* vmbus_alloc_requestor - Initializes @rqstor's fields.
|
|
* Index 0 is the first free slot
|
|
* @size: Size of the requestor array
|
|
*/
|
|
static int vmbus_alloc_requestor(struct vmbus_requestor *rqstor, u32 size)
|
|
{
|
|
u64 *rqst_arr;
|
|
unsigned long *bitmap;
|
|
|
|
rqst_arr = request_arr_init(size);
|
|
if (!rqst_arr)
|
|
return -ENOMEM;
|
|
|
|
bitmap = bitmap_zalloc(size, GFP_KERNEL);
|
|
if (!bitmap) {
|
|
kfree(rqst_arr);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
rqstor->req_arr = rqst_arr;
|
|
rqstor->req_bitmap = bitmap;
|
|
rqstor->size = size;
|
|
rqstor->next_request_id = 0;
|
|
spin_lock_init(&rqstor->req_lock);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* vmbus_free_requestor - Frees memory allocated for @rqstor
|
|
* @rqstor: Pointer to the requestor struct
|
|
*/
|
|
static void vmbus_free_requestor(struct vmbus_requestor *rqstor)
|
|
{
|
|
kfree(rqstor->req_arr);
|
|
bitmap_free(rqstor->req_bitmap);
|
|
}
|
|
|
|
static int __vmbus_open(struct vmbus_channel *newchannel,
|
|
void *userdata, u32 userdatalen,
|
|
void (*onchannelcallback)(void *context), void *context)
|
|
{
|
|
struct vmbus_channel_open_channel *open_msg;
|
|
struct vmbus_channel_msginfo *open_info = NULL;
|
|
struct page *page = newchannel->ringbuffer_page;
|
|
u32 send_pages, recv_pages;
|
|
unsigned long flags;
|
|
int err;
|
|
|
|
if (userdatalen > MAX_USER_DEFINED_BYTES)
|
|
return -EINVAL;
|
|
|
|
send_pages = newchannel->ringbuffer_send_offset;
|
|
recv_pages = newchannel->ringbuffer_pagecount - send_pages;
|
|
|
|
if (newchannel->state != CHANNEL_OPEN_STATE)
|
|
return -EINVAL;
|
|
|
|
/* Create and init requestor */
|
|
if (newchannel->rqstor_size) {
|
|
if (vmbus_alloc_requestor(&newchannel->requestor, newchannel->rqstor_size))
|
|
return -ENOMEM;
|
|
}
|
|
|
|
newchannel->state = CHANNEL_OPENING_STATE;
|
|
newchannel->onchannel_callback = onchannelcallback;
|
|
newchannel->channel_callback_context = context;
|
|
|
|
if (!newchannel->max_pkt_size)
|
|
newchannel->max_pkt_size = VMBUS_DEFAULT_MAX_PKT_SIZE;
|
|
|
|
err = hv_ringbuffer_init(&newchannel->outbound, page, send_pages, 0);
|
|
if (err)
|
|
goto error_clean_ring;
|
|
|
|
err = hv_ringbuffer_init(&newchannel->inbound, &page[send_pages],
|
|
recv_pages, newchannel->max_pkt_size);
|
|
if (err)
|
|
goto error_clean_ring;
|
|
|
|
/* Establish the gpadl for the ring buffer */
|
|
newchannel->ringbuffer_gpadlhandle = 0;
|
|
|
|
err = __vmbus_establish_gpadl(newchannel, HV_GPADL_RING,
|
|
page_address(newchannel->ringbuffer_page),
|
|
(send_pages + recv_pages) << PAGE_SHIFT,
|
|
newchannel->ringbuffer_send_offset << PAGE_SHIFT,
|
|
&newchannel->ringbuffer_gpadlhandle);
|
|
if (err)
|
|
goto error_clean_ring;
|
|
|
|
/* Create and init the channel open message */
|
|
open_info = kzalloc(sizeof(*open_info) +
|
|
sizeof(struct vmbus_channel_open_channel),
|
|
GFP_KERNEL);
|
|
if (!open_info) {
|
|
err = -ENOMEM;
|
|
goto error_free_gpadl;
|
|
}
|
|
|
|
init_completion(&open_info->waitevent);
|
|
open_info->waiting_channel = newchannel;
|
|
|
|
open_msg = (struct vmbus_channel_open_channel *)open_info->msg;
|
|
open_msg->header.msgtype = CHANNELMSG_OPENCHANNEL;
|
|
open_msg->openid = newchannel->offermsg.child_relid;
|
|
open_msg->child_relid = newchannel->offermsg.child_relid;
|
|
open_msg->ringbuffer_gpadlhandle = newchannel->ringbuffer_gpadlhandle;
|
|
/*
|
|
* The unit of ->downstream_ringbuffer_pageoffset is HV_HYP_PAGE and
|
|
* the unit of ->ringbuffer_send_offset (i.e. send_pages) is PAGE, so
|
|
* here we calculate it into HV_HYP_PAGE.
|
|
*/
|
|
open_msg->downstream_ringbuffer_pageoffset =
|
|
hv_ring_gpadl_send_hvpgoffset(send_pages << PAGE_SHIFT);
|
|
open_msg->target_vp = hv_cpu_number_to_vp_number(newchannel->target_cpu);
|
|
|
|
if (userdatalen)
|
|
memcpy(open_msg->userdata, userdata, userdatalen);
|
|
|
|
spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
|
|
list_add_tail(&open_info->msglistentry,
|
|
&vmbus_connection.chn_msg_list);
|
|
spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
|
|
|
|
if (newchannel->rescind) {
|
|
err = -ENODEV;
|
|
goto error_clean_msglist;
|
|
}
|
|
|
|
err = vmbus_post_msg(open_msg,
|
|
sizeof(struct vmbus_channel_open_channel), true);
|
|
|
|
trace_vmbus_open(open_msg, err);
|
|
|
|
if (err != 0)
|
|
goto error_clean_msglist;
|
|
|
|
wait_for_completion(&open_info->waitevent);
|
|
|
|
spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
|
|
list_del(&open_info->msglistentry);
|
|
spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
|
|
|
|
if (newchannel->rescind) {
|
|
err = -ENODEV;
|
|
goto error_free_info;
|
|
}
|
|
|
|
if (open_info->response.open_result.status) {
|
|
err = -EAGAIN;
|
|
goto error_free_info;
|
|
}
|
|
|
|
newchannel->state = CHANNEL_OPENED_STATE;
|
|
kfree(open_info);
|
|
return 0;
|
|
|
|
error_clean_msglist:
|
|
spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
|
|
list_del(&open_info->msglistentry);
|
|
spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
|
|
error_free_info:
|
|
kfree(open_info);
|
|
error_free_gpadl:
|
|
vmbus_teardown_gpadl(newchannel, newchannel->ringbuffer_gpadlhandle);
|
|
newchannel->ringbuffer_gpadlhandle = 0;
|
|
error_clean_ring:
|
|
hv_ringbuffer_cleanup(&newchannel->outbound);
|
|
hv_ringbuffer_cleanup(&newchannel->inbound);
|
|
vmbus_free_requestor(&newchannel->requestor);
|
|
newchannel->state = CHANNEL_OPEN_STATE;
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* vmbus_connect_ring - Open the channel but reuse ring buffer
|
|
*/
|
|
int vmbus_connect_ring(struct vmbus_channel *newchannel,
|
|
void (*onchannelcallback)(void *context), void *context)
|
|
{
|
|
return __vmbus_open(newchannel, NULL, 0, onchannelcallback, context);
|
|
}
|
|
EXPORT_SYMBOL_GPL(vmbus_connect_ring);
|
|
|
|
/*
|
|
* vmbus_open - Open the specified channel.
|
|
*/
|
|
int vmbus_open(struct vmbus_channel *newchannel,
|
|
u32 send_ringbuffer_size, u32 recv_ringbuffer_size,
|
|
void *userdata, u32 userdatalen,
|
|
void (*onchannelcallback)(void *context), void *context)
|
|
{
|
|
int err;
|
|
|
|
err = vmbus_alloc_ring(newchannel, send_ringbuffer_size,
|
|
recv_ringbuffer_size);
|
|
if (err)
|
|
return err;
|
|
|
|
err = __vmbus_open(newchannel, userdata, userdatalen,
|
|
onchannelcallback, context);
|
|
if (err)
|
|
vmbus_free_ring(newchannel);
|
|
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL_GPL(vmbus_open);
|
|
|
|
/*
|
|
* vmbus_teardown_gpadl -Teardown the specified GPADL handle
|
|
*/
|
|
int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32 gpadl_handle)
|
|
{
|
|
struct vmbus_channel_gpadl_teardown *msg;
|
|
struct vmbus_channel_msginfo *info;
|
|
unsigned long flags;
|
|
int ret;
|
|
|
|
info = kzalloc(sizeof(*info) +
|
|
sizeof(struct vmbus_channel_gpadl_teardown), GFP_KERNEL);
|
|
if (!info)
|
|
return -ENOMEM;
|
|
|
|
init_completion(&info->waitevent);
|
|
info->waiting_channel = channel;
|
|
|
|
msg = (struct vmbus_channel_gpadl_teardown *)info->msg;
|
|
|
|
msg->header.msgtype = CHANNELMSG_GPADL_TEARDOWN;
|
|
msg->child_relid = channel->offermsg.child_relid;
|
|
msg->gpadl = gpadl_handle;
|
|
|
|
spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
|
|
list_add_tail(&info->msglistentry,
|
|
&vmbus_connection.chn_msg_list);
|
|
spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
|
|
|
|
if (channel->rescind)
|
|
goto post_msg_err;
|
|
|
|
ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_gpadl_teardown),
|
|
true);
|
|
|
|
trace_vmbus_teardown_gpadl(msg, ret);
|
|
|
|
if (ret)
|
|
goto post_msg_err;
|
|
|
|
wait_for_completion(&info->waitevent);
|
|
|
|
post_msg_err:
|
|
/*
|
|
* If the channel has been rescinded;
|
|
* we will be awakened by the rescind
|
|
* handler; set the error code to zero so we don't leak memory.
|
|
*/
|
|
if (channel->rescind)
|
|
ret = 0;
|
|
|
|
spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
|
|
list_del(&info->msglistentry);
|
|
spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
|
|
|
|
kfree(info);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(vmbus_teardown_gpadl);
|
|
|
|
void vmbus_reset_channel_cb(struct vmbus_channel *channel)
|
|
{
|
|
unsigned long flags;
|
|
|
|
/*
|
|
* vmbus_on_event(), running in the per-channel tasklet, can race
|
|
* with vmbus_close_internal() in the case of SMP guest, e.g., when
|
|
* the former is accessing channel->inbound.ring_buffer, the latter
|
|
* could be freeing the ring_buffer pages, so here we must stop it
|
|
* first.
|
|
*
|
|
* vmbus_chan_sched() might call the netvsc driver callback function
|
|
* that ends up scheduling NAPI work that accesses the ring buffer.
|
|
* At this point, we have to ensure that any such work is completed
|
|
* and that the channel ring buffer is no longer being accessed, cf.
|
|
* the calls to napi_disable() in netvsc_device_remove().
|
|
*/
|
|
tasklet_disable(&channel->callback_event);
|
|
|
|
/* See the inline comments in vmbus_chan_sched(). */
|
|
spin_lock_irqsave(&channel->sched_lock, flags);
|
|
channel->onchannel_callback = NULL;
|
|
spin_unlock_irqrestore(&channel->sched_lock, flags);
|
|
|
|
channel->sc_creation_callback = NULL;
|
|
|
|
/* Re-enable tasklet for use on re-open */
|
|
tasklet_enable(&channel->callback_event);
|
|
}
|
|
|
|
static int vmbus_close_internal(struct vmbus_channel *channel)
|
|
{
|
|
struct vmbus_channel_close_channel *msg;
|
|
int ret;
|
|
|
|
vmbus_reset_channel_cb(channel);
|
|
|
|
/*
|
|
* In case a device driver's probe() fails (e.g.,
|
|
* util_probe() -> vmbus_open() returns -ENOMEM) and the device is
|
|
* rescinded later (e.g., we dynamically disable an Integrated Service
|
|
* in Hyper-V Manager), the driver's remove() invokes vmbus_close():
|
|
* here we should skip most of the below cleanup work.
|
|
*/
|
|
if (channel->state != CHANNEL_OPENED_STATE)
|
|
return -EINVAL;
|
|
|
|
channel->state = CHANNEL_OPEN_STATE;
|
|
|
|
/* Send a closing message */
|
|
|
|
msg = &channel->close_msg.msg;
|
|
|
|
msg->header.msgtype = CHANNELMSG_CLOSECHANNEL;
|
|
msg->child_relid = channel->offermsg.child_relid;
|
|
|
|
ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_close_channel),
|
|
true);
|
|
|
|
trace_vmbus_close_internal(msg, ret);
|
|
|
|
if (ret) {
|
|
pr_err("Close failed: close post msg return is %d\n", ret);
|
|
/*
|
|
* If we failed to post the close msg,
|
|
* it is perhaps better to leak memory.
|
|
*/
|
|
}
|
|
|
|
/* Tear down the gpadl for the channel's ring buffer */
|
|
else if (channel->ringbuffer_gpadlhandle) {
|
|
ret = vmbus_teardown_gpadl(channel,
|
|
channel->ringbuffer_gpadlhandle);
|
|
if (ret) {
|
|
pr_err("Close failed: teardown gpadl return %d\n", ret);
|
|
/*
|
|
* If we failed to teardown gpadl,
|
|
* it is perhaps better to leak memory.
|
|
*/
|
|
}
|
|
|
|
channel->ringbuffer_gpadlhandle = 0;
|
|
}
|
|
|
|
if (!ret)
|
|
vmbus_free_requestor(&channel->requestor);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* disconnect ring - close all channels */
|
|
int vmbus_disconnect_ring(struct vmbus_channel *channel)
|
|
{
|
|
struct vmbus_channel *cur_channel, *tmp;
|
|
int ret;
|
|
|
|
if (channel->primary_channel != NULL)
|
|
return -EINVAL;
|
|
|
|
list_for_each_entry_safe(cur_channel, tmp, &channel->sc_list, sc_list) {
|
|
if (cur_channel->rescind)
|
|
wait_for_completion(&cur_channel->rescind_event);
|
|
|
|
mutex_lock(&vmbus_connection.channel_mutex);
|
|
if (vmbus_close_internal(cur_channel) == 0) {
|
|
vmbus_free_ring(cur_channel);
|
|
|
|
if (cur_channel->rescind)
|
|
hv_process_channel_removal(cur_channel);
|
|
}
|
|
mutex_unlock(&vmbus_connection.channel_mutex);
|
|
}
|
|
|
|
/*
|
|
* Now close the primary.
|
|
*/
|
|
mutex_lock(&vmbus_connection.channel_mutex);
|
|
ret = vmbus_close_internal(channel);
|
|
mutex_unlock(&vmbus_connection.channel_mutex);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(vmbus_disconnect_ring);
|
|
|
|
/*
|
|
* vmbus_close - Close the specified channel
|
|
*/
|
|
void vmbus_close(struct vmbus_channel *channel)
|
|
{
|
|
if (vmbus_disconnect_ring(channel) == 0)
|
|
vmbus_free_ring(channel);
|
|
}
|
|
EXPORT_SYMBOL_GPL(vmbus_close);
|
|
|
|
/**
|
|
* vmbus_sendpacket() - Send the specified buffer on the given channel
|
|
* @channel: Pointer to vmbus_channel structure
|
|
* @buffer: Pointer to the buffer you want to send the data from.
|
|
* @bufferlen: Maximum size of what the buffer holds.
|
|
* @requestid: Identifier of the request
|
|
* @type: Type of packet that is being sent e.g. negotiate, time
|
|
* packet etc.
|
|
* @flags: 0 or VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED
|
|
*
|
|
* Sends data in @buffer directly to Hyper-V via the vmbus.
|
|
* This will send the data unparsed to Hyper-V.
|
|
*
|
|
* Mainly used by Hyper-V drivers.
|
|
*/
|
|
int vmbus_sendpacket(struct vmbus_channel *channel, void *buffer,
|
|
u32 bufferlen, u64 requestid,
|
|
enum vmbus_packet_type type, u32 flags)
|
|
{
|
|
struct vmpacket_descriptor desc;
|
|
u32 packetlen = sizeof(struct vmpacket_descriptor) + bufferlen;
|
|
u32 packetlen_aligned = ALIGN(packetlen, sizeof(u64));
|
|
struct kvec bufferlist[3];
|
|
u64 aligned_data = 0;
|
|
int num_vecs = ((bufferlen != 0) ? 3 : 1);
|
|
|
|
|
|
/* Setup the descriptor */
|
|
desc.type = type; /* VmbusPacketTypeDataInBand; */
|
|
desc.flags = flags; /* VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED; */
|
|
/* in 8-bytes granularity */
|
|
desc.offset8 = sizeof(struct vmpacket_descriptor) >> 3;
|
|
desc.len8 = (u16)(packetlen_aligned >> 3);
|
|
desc.trans_id = VMBUS_RQST_ERROR; /* will be updated in hv_ringbuffer_write() */
|
|
|
|
bufferlist[0].iov_base = &desc;
|
|
bufferlist[0].iov_len = sizeof(struct vmpacket_descriptor);
|
|
bufferlist[1].iov_base = buffer;
|
|
bufferlist[1].iov_len = bufferlen;
|
|
bufferlist[2].iov_base = &aligned_data;
|
|
bufferlist[2].iov_len = (packetlen_aligned - packetlen);
|
|
|
|
return hv_ringbuffer_write(channel, bufferlist, num_vecs, requestid);
|
|
}
|
|
EXPORT_SYMBOL(vmbus_sendpacket);
|
|
|
|
/*
|
|
* vmbus_sendpacket_pagebuffer - Send a range of single-page buffer
|
|
* packets using a GPADL Direct packet type. This interface allows you
|
|
* to control notifying the host. This will be useful for sending
|
|
* batched data. Also the sender can control the send flags
|
|
* explicitly.
|
|
*/
|
|
int vmbus_sendpacket_pagebuffer(struct vmbus_channel *channel,
|
|
struct hv_page_buffer pagebuffers[],
|
|
u32 pagecount, void *buffer, u32 bufferlen,
|
|
u64 requestid)
|
|
{
|
|
int i;
|
|
struct vmbus_channel_packet_page_buffer desc;
|
|
u32 descsize;
|
|
u32 packetlen;
|
|
u32 packetlen_aligned;
|
|
struct kvec bufferlist[3];
|
|
u64 aligned_data = 0;
|
|
|
|
if (pagecount > MAX_PAGE_BUFFER_COUNT)
|
|
return -EINVAL;
|
|
|
|
/*
|
|
* Adjust the size down since vmbus_channel_packet_page_buffer is the
|
|
* largest size we support
|
|
*/
|
|
descsize = sizeof(struct vmbus_channel_packet_page_buffer) -
|
|
((MAX_PAGE_BUFFER_COUNT - pagecount) *
|
|
sizeof(struct hv_page_buffer));
|
|
packetlen = descsize + bufferlen;
|
|
packetlen_aligned = ALIGN(packetlen, sizeof(u64));
|
|
|
|
/* Setup the descriptor */
|
|
desc.type = VM_PKT_DATA_USING_GPA_DIRECT;
|
|
desc.flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
|
|
desc.dataoffset8 = descsize >> 3; /* in 8-bytes granularity */
|
|
desc.length8 = (u16)(packetlen_aligned >> 3);
|
|
desc.transactionid = VMBUS_RQST_ERROR; /* will be updated in hv_ringbuffer_write() */
|
|
desc.reserved = 0;
|
|
desc.rangecount = pagecount;
|
|
|
|
for (i = 0; i < pagecount; i++) {
|
|
desc.range[i].len = pagebuffers[i].len;
|
|
desc.range[i].offset = pagebuffers[i].offset;
|
|
desc.range[i].pfn = pagebuffers[i].pfn;
|
|
}
|
|
|
|
bufferlist[0].iov_base = &desc;
|
|
bufferlist[0].iov_len = descsize;
|
|
bufferlist[1].iov_base = buffer;
|
|
bufferlist[1].iov_len = bufferlen;
|
|
bufferlist[2].iov_base = &aligned_data;
|
|
bufferlist[2].iov_len = (packetlen_aligned - packetlen);
|
|
|
|
return hv_ringbuffer_write(channel, bufferlist, 3, requestid);
|
|
}
|
|
EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer);
|
|
|
|
/*
|
|
* vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
|
|
* using a GPADL Direct packet type.
|
|
* The buffer includes the vmbus descriptor.
|
|
*/
|
|
int vmbus_sendpacket_mpb_desc(struct vmbus_channel *channel,
|
|
struct vmbus_packet_mpb_array *desc,
|
|
u32 desc_size,
|
|
void *buffer, u32 bufferlen, u64 requestid)
|
|
{
|
|
u32 packetlen;
|
|
u32 packetlen_aligned;
|
|
struct kvec bufferlist[3];
|
|
u64 aligned_data = 0;
|
|
|
|
packetlen = desc_size + bufferlen;
|
|
packetlen_aligned = ALIGN(packetlen, sizeof(u64));
|
|
|
|
/* Setup the descriptor */
|
|
desc->type = VM_PKT_DATA_USING_GPA_DIRECT;
|
|
desc->flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
|
|
desc->dataoffset8 = desc_size >> 3; /* in 8-bytes granularity */
|
|
desc->length8 = (u16)(packetlen_aligned >> 3);
|
|
desc->transactionid = VMBUS_RQST_ERROR; /* will be updated in hv_ringbuffer_write() */
|
|
desc->reserved = 0;
|
|
desc->rangecount = 1;
|
|
|
|
bufferlist[0].iov_base = desc;
|
|
bufferlist[0].iov_len = desc_size;
|
|
bufferlist[1].iov_base = buffer;
|
|
bufferlist[1].iov_len = bufferlen;
|
|
bufferlist[2].iov_base = &aligned_data;
|
|
bufferlist[2].iov_len = (packetlen_aligned - packetlen);
|
|
|
|
return hv_ringbuffer_write(channel, bufferlist, 3, requestid);
|
|
}
|
|
EXPORT_SYMBOL_GPL(vmbus_sendpacket_mpb_desc);
|
|
|
|
/**
|
|
* __vmbus_recvpacket() - Retrieve the user packet on the specified channel
|
|
* @channel: Pointer to vmbus_channel structure
|
|
* @buffer: Pointer to the buffer you want to receive the data into.
|
|
* @bufferlen: Maximum size of what the buffer can hold.
|
|
* @buffer_actual_len: The actual size of the data after it was received.
|
|
* @requestid: Identifier of the request
|
|
* @raw: true means keep the vmpacket_descriptor header in the received data.
|
|
*
|
|
* Receives directly from the hyper-v vmbus and puts the data it received
|
|
* into Buffer. This will receive the data unparsed from hyper-v.
|
|
*
|
|
* Mainly used by Hyper-V drivers.
|
|
*/
|
|
static inline int
|
|
__vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
|
|
u32 bufferlen, u32 *buffer_actual_len, u64 *requestid,
|
|
bool raw)
|
|
{
|
|
return hv_ringbuffer_read(channel, buffer, bufferlen,
|
|
buffer_actual_len, requestid, raw);
|
|
|
|
}
|
|
|
|
int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
|
|
u32 bufferlen, u32 *buffer_actual_len,
|
|
u64 *requestid)
|
|
{
|
|
return __vmbus_recvpacket(channel, buffer, bufferlen,
|
|
buffer_actual_len, requestid, false);
|
|
}
|
|
EXPORT_SYMBOL(vmbus_recvpacket);
|
|
|
|
/*
|
|
* vmbus_recvpacket_raw - Retrieve the raw packet on the specified channel
|
|
*/
|
|
int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer,
|
|
u32 bufferlen, u32 *buffer_actual_len,
|
|
u64 *requestid)
|
|
{
|
|
return __vmbus_recvpacket(channel, buffer, bufferlen,
|
|
buffer_actual_len, requestid, true);
|
|
}
|
|
EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);
|
|
|
|
/*
|
|
* vmbus_next_request_id - Returns a new request id. It is also
|
|
* the index at which the guest memory address is stored.
|
|
* Uses a spin lock to avoid race conditions.
|
|
* @channel: Pointer to the VMbus channel struct
|
|
* @rqst_add: Guest memory address to be stored in the array
|
|
*/
|
|
u64 vmbus_next_request_id(struct vmbus_channel *channel, u64 rqst_addr)
|
|
{
|
|
struct vmbus_requestor *rqstor = &channel->requestor;
|
|
unsigned long flags;
|
|
u64 current_id;
|
|
|
|
/* Check rqstor has been initialized */
|
|
if (!channel->rqstor_size)
|
|
return VMBUS_NO_RQSTOR;
|
|
|
|
spin_lock_irqsave(&rqstor->req_lock, flags);
|
|
current_id = rqstor->next_request_id;
|
|
|
|
/* Requestor array is full */
|
|
if (current_id >= rqstor->size) {
|
|
spin_unlock_irqrestore(&rqstor->req_lock, flags);
|
|
return VMBUS_RQST_ERROR;
|
|
}
|
|
|
|
rqstor->next_request_id = rqstor->req_arr[current_id];
|
|
rqstor->req_arr[current_id] = rqst_addr;
|
|
|
|
/* The already held spin lock provides atomicity */
|
|
bitmap_set(rqstor->req_bitmap, current_id, 1);
|
|
|
|
spin_unlock_irqrestore(&rqstor->req_lock, flags);
|
|
|
|
/*
|
|
* Cannot return an ID of 0, which is reserved for an unsolicited
|
|
* message from Hyper-V.
|
|
*/
|
|
return current_id + 1;
|
|
}
|
|
EXPORT_SYMBOL_GPL(vmbus_next_request_id);
|
|
|
|
/*
|
|
* vmbus_request_addr - Returns the memory address stored at @trans_id
|
|
* in @rqstor. Uses a spin lock to avoid race conditions.
|
|
* @channel: Pointer to the VMbus channel struct
|
|
* @trans_id: Request id sent back from Hyper-V. Becomes the requestor's
|
|
* next request id.
|
|
*/
|
|
u64 vmbus_request_addr(struct vmbus_channel *channel, u64 trans_id)
|
|
{
|
|
struct vmbus_requestor *rqstor = &channel->requestor;
|
|
unsigned long flags;
|
|
u64 req_addr;
|
|
|
|
/* Check rqstor has been initialized */
|
|
if (!channel->rqstor_size)
|
|
return VMBUS_NO_RQSTOR;
|
|
|
|
/* Hyper-V can send an unsolicited message with ID of 0 */
|
|
if (!trans_id)
|
|
return trans_id;
|
|
|
|
spin_lock_irqsave(&rqstor->req_lock, flags);
|
|
|
|
/* Data corresponding to trans_id is stored at trans_id - 1 */
|
|
trans_id--;
|
|
|
|
/* Invalid trans_id */
|
|
if (trans_id >= rqstor->size || !test_bit(trans_id, rqstor->req_bitmap)) {
|
|
spin_unlock_irqrestore(&rqstor->req_lock, flags);
|
|
return VMBUS_RQST_ERROR;
|
|
}
|
|
|
|
req_addr = rqstor->req_arr[trans_id];
|
|
rqstor->req_arr[trans_id] = rqstor->next_request_id;
|
|
rqstor->next_request_id = trans_id;
|
|
|
|
/* The already held spin lock provides atomicity */
|
|
bitmap_clear(rqstor->req_bitmap, trans_id, 1);
|
|
|
|
spin_unlock_irqrestore(&rqstor->req_lock, flags);
|
|
return req_addr;
|
|
}
|
|
EXPORT_SYMBOL_GPL(vmbus_request_addr);
|