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vdpa-dev: Fix initialisation order to restore VDUSE compatibility

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VDUSE requires that virtqueues are first enabled before the DRIVER_OK
status flag is set; with the current API of the kernel module, it is
impossible to enable the opposite order in our block export code because
userspace is not notified when a virtqueue is enabled.

This requirement also mathces the normal initialisation order as done by
the generic vhost code in QEMU. However, commit 6c482547 accidentally
changed the order for vdpa-dev and broke access to VDUSE devices with
this.

This changes vdpa-dev to use the normal order again and use the standard
vhost callback .vhost_set_vring_enable for this. VDUSE devices can be
used with vdpa-dev again after this fix.

vhost_net intentionally avoided enabling the vrings for vdpa and does
this manually later while it does enable them for other vhost backends.
Reflect this in the vhost_net code and return early for vdpa, so that
the behaviour doesn't change for this device.

Cc: qemu-stable@nongnu.org
Fixes: 6c4825476a43 ('vdpa: move vhost_vdpa_set_vring_ready to the caller')
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20240315155949.86066-1-kwolf@redhat.com>
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Kevin Wolf 2024-03-15 16:59:49 +01:00
parent d9e4070603
commit 2c66de61f8
5 changed files with 45 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
hw/net/vhost_net.c
View File

@ -541,6 +541,16 @@ int vhost_set_vring_enable(NetClientState *nc, int enable)
VHostNetState *net = get_vhost_net(nc);
const VhostOps *vhost_ops = net->dev.vhost_ops;
/*
* vhost-vdpa network devices need to enable dataplane virtqueues after
* DRIVER_OK, so they can recover device state before starting dataplane.
* Because of that, we don't enable virtqueues here and leave it to
* net/vhost-vdpa.c.
*/
if (nc->info->type == NET_CLIENT_DRIVER_VHOST_VDPA) {
return 0;
}
nc->vring_enable = enable;
if (vhost_ops && vhost_ops->vhost_set_vring_enable) {

2
hw/virtio/trace-events
View File

@ -49,7 +49,7 @@ vhost_vdpa_set_features(void *dev, uint64_t features) "dev: %p features: 0x%"PRI
vhost_vdpa_get_device_id(void *dev, uint32_t device_id) "dev: %p device_id %"PRIu32
vhost_vdpa_reset_device(void *dev) "dev: %p"
vhost_vdpa_get_vq_index(void *dev, int idx, int vq_idx) "dev: %p idx: %d vq idx: %d"
vhost_vdpa_set_vring_ready(void *dev, unsigned i, int r) "dev: %p, idx: %u, r: %d"
vhost_vdpa_set_vring_enable_one(void *dev, unsigned i, int enable, int r) "dev: %p, idx: %u, enable: %u, r: %d"
vhost_vdpa_dump_config(void *dev, const char *line) "dev: %p %s"
vhost_vdpa_set_config(void *dev, uint32_t offset, uint32_t size, uint32_t flags) "dev: %p offset: %"PRIu32" size: %"PRIu32" flags: 0x%"PRIx32
vhost_vdpa_get_config(void *dev, void *config, uint32_t config_len) "dev: %p config: %p config_len: %"PRIu32

5
hw/virtio/vdpa-dev.c
View File

@ -253,14 +253,11 @@ static int vhost_vdpa_device_start(VirtIODevice *vdev, Error **errp)
s->dev.acked_features = vdev->guest_features;
ret = vhost_dev_start(&s->dev, vdev, false);
ret = vhost_dev_start(&s->dev, vdev, true);
if (ret < 0) {
error_setg_errno(errp, -ret, "Error starting vhost");
goto err_guest_notifiers;
}
for (i = 0; i < s->dev.nvqs; ++i) {
vhost_vdpa_set_vring_ready(&s->vdpa, i);
}
s->started = true;
/*

29
hw/virtio/vhost-vdpa.c
View File

@ -896,19 +896,41 @@ static int vhost_vdpa_get_vq_index(struct vhost_dev *dev, int idx)
return idx;
}
int vhost_vdpa_set_vring_ready(struct vhost_vdpa *v, unsigned idx)
static int vhost_vdpa_set_vring_enable_one(struct vhost_vdpa *v, unsigned idx,
int enable)
{
struct vhost_dev *dev = v->dev;
struct vhost_vring_state state = {
.index = idx,
.num = 1,
.num = enable,
};
int r = vhost_vdpa_call(dev, VHOST_VDPA_SET_VRING_ENABLE, &state);
trace_vhost_vdpa_set_vring_ready(dev, idx, r);
trace_vhost_vdpa_set_vring_enable_one(dev, idx, enable, r);
return r;
}
static int vhost_vdpa_set_vring_enable(struct vhost_dev *dev, int enable)
{
struct vhost_vdpa *v = dev->opaque;
unsigned int i;
int ret;
for (i = 0; i < dev->nvqs; ++i) {
ret = vhost_vdpa_set_vring_enable_one(v, i, enable);
if (ret < 0) {
return ret;
}
}
return 0;
}
int vhost_vdpa_set_vring_ready(struct vhost_vdpa *v, unsigned idx)
{
return vhost_vdpa_set_vring_enable_one(v, idx, 1);
}
static int vhost_vdpa_set_config_call(struct vhost_dev *dev,
int fd)
{
@ -1536,6 +1558,7 @@ const VhostOps vdpa_ops = {
.vhost_set_features = vhost_vdpa_set_features,
.vhost_reset_device = vhost_vdpa_reset_device,
.vhost_get_vq_index = vhost_vdpa_get_vq_index,
.vhost_set_vring_enable = vhost_vdpa_set_vring_enable,
.vhost_get_config = vhost_vdpa_get_config,
.vhost_set_config = vhost_vdpa_set_config,
.vhost_requires_shm_log = NULL,

8
hw/virtio/vhost.c
View File

@ -1984,7 +1984,13 @@ static int vhost_dev_set_vring_enable(struct vhost_dev *hdev, int enable)
return hdev->vhost_ops->vhost_set_vring_enable(hdev, enable);
}
/* Host notifiers must be enabled at this point. */
/*
* Host notifiers must be enabled at this point.
*
* If @vrings is true, this function will enable all vrings before starting the
* device. If it is false, the vring initialization is left to be done by the
* caller.
*/
int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev, bool vrings)
{
int i, r;