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![Gautam Dawar](/assets/img/avatar_default.png)
This patch introduces the control virtqueue support for vDPA simulator. This is a requirement for supporting advanced features like multiqueue. A requirement for control virtqueue is to isolate its memory access from the rx/tx virtqueues. This is because when using vDPA device for VM, the control virqueue is not directly assigned to VM. Userspace (Qemu) will present a shadow control virtqueue to control for recording the device states. The isolation is done via the virtqueue groups and ASID support in vDPA through vhost-vdpa. The simulator is extended to have: 1) three virtqueues: RXVQ, TXVQ and CVQ (control virtqueue) 2) two virtqueue groups: group 0 contains RXVQ and TXVQ; group 1 contains CVQ 3) two address spaces and the simulator simply implements the address spaces by mapping it 1:1 to IOTLB. For the VM use cases, userspace(Qemu) may set AS 0 to group 0 and AS 1 to group 1. So we have: 1) The IOTLB for virtqueue group 0 contains the mappings of guest, so RX and TX can be assigned to guest directly. 2) The IOTLB for virtqueue group 1 contains the mappings of CVQ which is the buffers that allocated and managed by VMM only. So CVQ of vhost-vdpa is visible to VMM only. And Guest can not access the CVQ of vhost-vdpa. For the other use cases, since AS 0 is associated to all virtqueue groups by default. All virtqueues share the same mapping by default. To demonstrate the function, VIRITO_NET_F_CTRL_MACADDR is implemented in the simulator for the driver to set mac address. Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Gautam Dawar <gdawar@xilinx.com> Message-Id: <20220330180436.24644-20-gdawar@xilinx.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
329 lines
7.8 KiB
C
329 lines
7.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* VDPA simulator for networking device.
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*
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* Copyright (c) 2020, Red Hat Inc. All rights reserved.
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* Author: Jason Wang <jasowang@redhat.com>
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*
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/device.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/etherdevice.h>
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#include <linux/vringh.h>
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#include <linux/vdpa.h>
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#include <uapi/linux/virtio_net.h>
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#include <uapi/linux/vdpa.h>
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#include "vdpa_sim.h"
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#define DRV_VERSION "0.1"
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#define DRV_AUTHOR "Jason Wang <jasowang@redhat.com>"
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#define DRV_DESC "vDPA Device Simulator for networking device"
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#define DRV_LICENSE "GPL v2"
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#define VDPASIM_NET_FEATURES (VDPASIM_FEATURES | \
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(1ULL << VIRTIO_NET_F_MAC) | \
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(1ULL << VIRTIO_NET_F_MTU) | \
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(1ULL << VIRTIO_NET_F_CTRL_VQ) | \
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(1ULL << VIRTIO_NET_F_CTRL_MAC_ADDR))
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/* 3 virtqueues, 2 address spaces, 2 virtqueue groups */
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#define VDPASIM_NET_VQ_NUM 3
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#define VDPASIM_NET_AS_NUM 2
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#define VDPASIM_NET_GROUP_NUM 2
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static void vdpasim_net_complete(struct vdpasim_virtqueue *vq, size_t len)
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{
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/* Make sure data is wrote before advancing index */
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smp_wmb();
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vringh_complete_iotlb(&vq->vring, vq->head, len);
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/* Make sure used is visible before rasing the interrupt. */
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smp_wmb();
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local_bh_disable();
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if (vringh_need_notify_iotlb(&vq->vring) > 0)
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vringh_notify(&vq->vring);
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local_bh_enable();
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}
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static bool receive_filter(struct vdpasim *vdpasim, size_t len)
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{
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bool modern = vdpasim->features & (1ULL << VIRTIO_F_VERSION_1);
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size_t hdr_len = modern ? sizeof(struct virtio_net_hdr_v1) :
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sizeof(struct virtio_net_hdr);
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struct virtio_net_config *vio_config = vdpasim->config;
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if (len < ETH_ALEN + hdr_len)
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return false;
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if (!strncmp(vdpasim->buffer + hdr_len, vio_config->mac, ETH_ALEN))
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return true;
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return false;
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}
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static virtio_net_ctrl_ack vdpasim_handle_ctrl_mac(struct vdpasim *vdpasim,
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u8 cmd)
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{
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struct virtio_net_config *vio_config = vdpasim->config;
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struct vdpasim_virtqueue *cvq = &vdpasim->vqs[2];
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virtio_net_ctrl_ack status = VIRTIO_NET_ERR;
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size_t read;
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switch (cmd) {
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case VIRTIO_NET_CTRL_MAC_ADDR_SET:
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read = vringh_iov_pull_iotlb(&cvq->vring, &cvq->in_iov,
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vio_config->mac, ETH_ALEN);
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if (read == ETH_ALEN)
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status = VIRTIO_NET_OK;
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break;
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default:
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break;
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}
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return status;
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}
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static void vdpasim_handle_cvq(struct vdpasim *vdpasim)
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{
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struct vdpasim_virtqueue *cvq = &vdpasim->vqs[2];
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virtio_net_ctrl_ack status = VIRTIO_NET_ERR;
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struct virtio_net_ctrl_hdr ctrl;
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size_t read, write;
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int err;
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if (!(vdpasim->features & (1ULL << VIRTIO_NET_F_CTRL_VQ)))
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return;
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if (!cvq->ready)
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return;
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while (true) {
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err = vringh_getdesc_iotlb(&cvq->vring, &cvq->in_iov,
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&cvq->out_iov,
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&cvq->head, GFP_ATOMIC);
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if (err <= 0)
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break;
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read = vringh_iov_pull_iotlb(&cvq->vring, &cvq->in_iov, &ctrl,
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sizeof(ctrl));
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if (read != sizeof(ctrl))
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break;
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switch (ctrl.class) {
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case VIRTIO_NET_CTRL_MAC:
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status = vdpasim_handle_ctrl_mac(vdpasim, ctrl.cmd);
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break;
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default:
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break;
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}
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/* Make sure data is wrote before advancing index */
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smp_wmb();
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write = vringh_iov_push_iotlb(&cvq->vring, &cvq->out_iov,
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&status, sizeof(status));
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vringh_complete_iotlb(&cvq->vring, cvq->head, write);
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vringh_kiov_cleanup(&cvq->in_iov);
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vringh_kiov_cleanup(&cvq->out_iov);
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/* Make sure used is visible before rasing the interrupt. */
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smp_wmb();
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local_bh_disable();
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if (cvq->cb)
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cvq->cb(cvq->private);
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local_bh_enable();
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}
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}
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static void vdpasim_net_work(struct work_struct *work)
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{
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struct vdpasim *vdpasim = container_of(work, struct vdpasim, work);
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struct vdpasim_virtqueue *txq = &vdpasim->vqs[1];
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struct vdpasim_virtqueue *rxq = &vdpasim->vqs[0];
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ssize_t read, write;
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int pkts = 0;
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int err;
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spin_lock(&vdpasim->lock);
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if (!(vdpasim->status & VIRTIO_CONFIG_S_DRIVER_OK))
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goto out;
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vdpasim_handle_cvq(vdpasim);
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if (!txq->ready || !rxq->ready)
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goto out;
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while (true) {
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err = vringh_getdesc_iotlb(&txq->vring, &txq->out_iov, NULL,
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&txq->head, GFP_ATOMIC);
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if (err <= 0)
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break;
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read = vringh_iov_pull_iotlb(&txq->vring, &txq->out_iov,
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vdpasim->buffer,
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PAGE_SIZE);
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if (!receive_filter(vdpasim, read)) {
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vdpasim_net_complete(txq, 0);
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continue;
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}
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err = vringh_getdesc_iotlb(&rxq->vring, NULL, &rxq->in_iov,
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&rxq->head, GFP_ATOMIC);
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if (err <= 0) {
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vdpasim_net_complete(txq, 0);
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break;
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}
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write = vringh_iov_push_iotlb(&rxq->vring, &rxq->in_iov,
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vdpasim->buffer, read);
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if (write <= 0)
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break;
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vdpasim_net_complete(txq, 0);
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vdpasim_net_complete(rxq, write);
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if (++pkts > 4) {
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schedule_work(&vdpasim->work);
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goto out;
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}
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}
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out:
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spin_unlock(&vdpasim->lock);
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}
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static void vdpasim_net_get_config(struct vdpasim *vdpasim, void *config)
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{
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struct virtio_net_config *net_config = config;
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net_config->status = cpu_to_vdpasim16(vdpasim, VIRTIO_NET_S_LINK_UP);
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}
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static void vdpasim_net_setup_config(struct vdpasim *vdpasim,
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const struct vdpa_dev_set_config *config)
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{
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struct virtio_net_config *vio_config = vdpasim->config;
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if (config->mask & (1 << VDPA_ATTR_DEV_NET_CFG_MACADDR))
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memcpy(vio_config->mac, config->net.mac, ETH_ALEN);
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if (config->mask & (1 << VDPA_ATTR_DEV_NET_CFG_MTU))
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vio_config->mtu = cpu_to_vdpasim16(vdpasim, config->net.mtu);
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else
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/* Setup default MTU to be 1500 */
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vio_config->mtu = cpu_to_vdpasim16(vdpasim, 1500);
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}
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static void vdpasim_net_mgmtdev_release(struct device *dev)
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{
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}
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static struct device vdpasim_net_mgmtdev = {
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.init_name = "vdpasim_net",
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.release = vdpasim_net_mgmtdev_release,
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};
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static int vdpasim_net_dev_add(struct vdpa_mgmt_dev *mdev, const char *name,
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const struct vdpa_dev_set_config *config)
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{
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struct vdpasim_dev_attr dev_attr = {};
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struct vdpasim *simdev;
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int ret;
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dev_attr.mgmt_dev = mdev;
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dev_attr.name = name;
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dev_attr.id = VIRTIO_ID_NET;
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dev_attr.supported_features = VDPASIM_NET_FEATURES;
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dev_attr.nvqs = VDPASIM_NET_VQ_NUM;
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dev_attr.ngroups = VDPASIM_NET_GROUP_NUM;
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dev_attr.nas = VDPASIM_NET_AS_NUM;
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dev_attr.config_size = sizeof(struct virtio_net_config);
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dev_attr.get_config = vdpasim_net_get_config;
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dev_attr.work_fn = vdpasim_net_work;
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dev_attr.buffer_size = PAGE_SIZE;
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simdev = vdpasim_create(&dev_attr);
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if (IS_ERR(simdev))
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return PTR_ERR(simdev);
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vdpasim_net_setup_config(simdev, config);
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ret = _vdpa_register_device(&simdev->vdpa, VDPASIM_NET_VQ_NUM);
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if (ret)
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goto reg_err;
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return 0;
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reg_err:
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put_device(&simdev->vdpa.dev);
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return ret;
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}
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static void vdpasim_net_dev_del(struct vdpa_mgmt_dev *mdev,
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struct vdpa_device *dev)
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{
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struct vdpasim *simdev = container_of(dev, struct vdpasim, vdpa);
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_vdpa_unregister_device(&simdev->vdpa);
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}
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static const struct vdpa_mgmtdev_ops vdpasim_net_mgmtdev_ops = {
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.dev_add = vdpasim_net_dev_add,
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.dev_del = vdpasim_net_dev_del
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};
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static struct virtio_device_id id_table[] = {
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{ VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
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{ 0 },
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};
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static struct vdpa_mgmt_dev mgmt_dev = {
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.device = &vdpasim_net_mgmtdev,
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.id_table = id_table,
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.ops = &vdpasim_net_mgmtdev_ops,
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.config_attr_mask = (1 << VDPA_ATTR_DEV_NET_CFG_MACADDR |
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1 << VDPA_ATTR_DEV_NET_CFG_MTU),
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.max_supported_vqs = VDPASIM_NET_VQ_NUM,
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.supported_features = VDPASIM_NET_FEATURES,
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};
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static int __init vdpasim_net_init(void)
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{
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int ret;
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ret = device_register(&vdpasim_net_mgmtdev);
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if (ret)
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return ret;
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ret = vdpa_mgmtdev_register(&mgmt_dev);
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if (ret)
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goto parent_err;
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return 0;
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parent_err:
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device_unregister(&vdpasim_net_mgmtdev);
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return ret;
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}
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static void __exit vdpasim_net_exit(void)
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{
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vdpa_mgmtdev_unregister(&mgmt_dev);
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device_unregister(&vdpasim_net_mgmtdev);
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}
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module_init(vdpasim_net_init);
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module_exit(vdpasim_net_exit);
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MODULE_VERSION(DRV_VERSION);
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MODULE_LICENSE(DRV_LICENSE);
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MODULE_AUTHOR(DRV_AUTHOR);
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MODULE_DESCRIPTION(DRV_DESC);
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