qemu/hw/virtio/vhost-vsock.c
Stefano Garzarella 384c2561bd vhost-vsock: set vhostfd to non-blocking mode
vhost IOTLB API uses read()/write() to exchange iotlb messages with
the kernel module.
The QEMU implementation expects a non-blocking fd, indeed commit
c471ad0e9b ("vhost_net: device IOTLB support") set it for vhost-net.

Without this patch, if we enable iommu for the vhost-vsock device,
QEMU can hang when exchanging IOTLB messages.

As commit 894022e616 ("net: check if the file descriptor is valid
before using it") did for tap, let's use qemu_try_set_nonblock()
when fd is provided by the user.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Message-Id: <20201029144849.70958-1-sgarzare@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2020-10-30 04:29:13 -04:00

244 lines
6.6 KiB
C

/*
* Virtio vsock device
*
* Copyright 2015 Red Hat, Inc.
*
* Authors:
* Stefan Hajnoczi <stefanha@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or
* (at your option) any later version. See the COPYING file in the
* top-level directory.
*/
#include "qemu/osdep.h"
#include "standard-headers/linux/virtio_vsock.h"
#include "qapi/error.h"
#include "hw/virtio/virtio-access.h"
#include "qemu/error-report.h"
#include "qemu/sockets.h"
#include "hw/qdev-properties.h"
#include "hw/virtio/vhost-vsock.h"
#include "monitor/monitor.h"
static void vhost_vsock_get_config(VirtIODevice *vdev, uint8_t *config)
{
VHostVSock *vsock = VHOST_VSOCK(vdev);
struct virtio_vsock_config vsockcfg = {};
virtio_stq_p(vdev, &vsockcfg.guest_cid, vsock->conf.guest_cid);
memcpy(config, &vsockcfg, sizeof(vsockcfg));
}
static int vhost_vsock_set_guest_cid(VirtIODevice *vdev)
{
VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(vdev);
VHostVSock *vsock = VHOST_VSOCK(vdev);
const VhostOps *vhost_ops = vvc->vhost_dev.vhost_ops;
int ret;
if (!vhost_ops->vhost_vsock_set_guest_cid) {
return -ENOSYS;
}
ret = vhost_ops->vhost_vsock_set_guest_cid(&vvc->vhost_dev,
vsock->conf.guest_cid);
if (ret < 0) {
return -errno;
}
return 0;
}
static int vhost_vsock_set_running(VirtIODevice *vdev, int start)
{
VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(vdev);
const VhostOps *vhost_ops = vvc->vhost_dev.vhost_ops;
int ret;
if (!vhost_ops->vhost_vsock_set_running) {
return -ENOSYS;
}
ret = vhost_ops->vhost_vsock_set_running(&vvc->vhost_dev, start);
if (ret < 0) {
return -errno;
}
return 0;
}
static void vhost_vsock_set_status(VirtIODevice *vdev, uint8_t status)
{
VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(vdev);
bool should_start = status & VIRTIO_CONFIG_S_DRIVER_OK;
int ret;
if (!vdev->vm_running) {
should_start = false;
}
if (vvc->vhost_dev.started == should_start) {
return;
}
if (should_start) {
ret = vhost_vsock_common_start(vdev);
if (ret < 0) {
return;
}
ret = vhost_vsock_set_running(vdev, 1);
if (ret < 0) {
vhost_vsock_common_stop(vdev);
error_report("Error starting vhost vsock: %d", -ret);
return;
}
} else {
ret = vhost_vsock_set_running(vdev, 0);
if (ret < 0) {
error_report("vhost vsock set running failed: %d", ret);
return;
}
vhost_vsock_common_stop(vdev);
}
}
static uint64_t vhost_vsock_get_features(VirtIODevice *vdev,
uint64_t requested_features,
Error **errp)
{
/* No feature bits used yet */
return requested_features;
}
static const VMStateDescription vmstate_virtio_vhost_vsock = {
.name = "virtio-vhost_vsock",
.minimum_version_id = VHOST_VSOCK_SAVEVM_VERSION,
.version_id = VHOST_VSOCK_SAVEVM_VERSION,
.fields = (VMStateField[]) {
VMSTATE_VIRTIO_DEVICE,
VMSTATE_END_OF_LIST()
},
.pre_save = vhost_vsock_common_pre_save,
.post_load = vhost_vsock_common_post_load,
};
static void vhost_vsock_device_realize(DeviceState *dev, Error **errp)
{
VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(dev);
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VHostVSock *vsock = VHOST_VSOCK(dev);
int vhostfd;
int ret;
/* Refuse to use reserved CID numbers */
if (vsock->conf.guest_cid <= 2) {
error_setg(errp, "guest-cid property must be greater than 2");
return;
}
if (vsock->conf.guest_cid > UINT32_MAX) {
error_setg(errp, "guest-cid property must be a 32-bit number");
return;
}
if (vsock->conf.vhostfd) {
vhostfd = monitor_fd_param(monitor_cur(), vsock->conf.vhostfd, errp);
if (vhostfd == -1) {
error_prepend(errp, "vhost-vsock: unable to parse vhostfd: ");
return;
}
ret = qemu_try_set_nonblock(vhostfd);
if (ret < 0) {
error_setg_errno(errp, -ret,
"vhost-vsock: unable to set non-blocking mode");
return;
}
} else {
vhostfd = open("/dev/vhost-vsock", O_RDWR);
if (vhostfd < 0) {
error_setg_errno(errp, errno,
"vhost-vsock: failed to open vhost device");
return;
}
qemu_set_nonblock(vhostfd);
}
vhost_vsock_common_realize(vdev, "vhost-vsock");
ret = vhost_dev_init(&vvc->vhost_dev, (void *)(uintptr_t)vhostfd,
VHOST_BACKEND_TYPE_KERNEL, 0);
if (ret < 0) {
error_setg_errno(errp, -ret, "vhost-vsock: vhost_dev_init failed");
goto err_virtio;
}
ret = vhost_vsock_set_guest_cid(vdev);
if (ret < 0) {
error_setg_errno(errp, -ret, "vhost-vsock: unable to set guest cid");
goto err_vhost_dev;
}
return;
err_vhost_dev:
vhost_dev_cleanup(&vvc->vhost_dev);
/* vhost_dev_cleanup() closes the vhostfd passed to vhost_dev_init() */
vhostfd = -1;
err_virtio:
vhost_vsock_common_unrealize(vdev);
if (vhostfd >= 0) {
close(vhostfd);
}
return;
}
static void vhost_vsock_device_unrealize(DeviceState *dev)
{
VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(dev);
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
/* This will stop vhost backend if appropriate. */
vhost_vsock_set_status(vdev, 0);
vhost_dev_cleanup(&vvc->vhost_dev);
vhost_vsock_common_unrealize(vdev);
}
static Property vhost_vsock_properties[] = {
DEFINE_PROP_UINT64("guest-cid", VHostVSock, conf.guest_cid, 0),
DEFINE_PROP_STRING("vhostfd", VHostVSock, conf.vhostfd),
DEFINE_PROP_END_OF_LIST(),
};
static void vhost_vsock_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
device_class_set_props(dc, vhost_vsock_properties);
dc->vmsd = &vmstate_virtio_vhost_vsock;
vdc->realize = vhost_vsock_device_realize;
vdc->unrealize = vhost_vsock_device_unrealize;
vdc->get_features = vhost_vsock_get_features;
vdc->get_config = vhost_vsock_get_config;
vdc->set_status = vhost_vsock_set_status;
}
static const TypeInfo vhost_vsock_info = {
.name = TYPE_VHOST_VSOCK,
.parent = TYPE_VHOST_VSOCK_COMMON,
.instance_size = sizeof(VHostVSock),
.class_init = vhost_vsock_class_init,
};
static void vhost_vsock_register_types(void)
{
type_register_static(&vhost_vsock_info);
}
type_init(vhost_vsock_register_types)