[PATCH vhost v4 07/15] vdpa: Block vq address change in DRIVER_OK unless device supports it

Dragos Tatulea
2023-12-19T18:09:50Z

Virtqueue address change during DRIVE_OK is not supported by the virtio
standard. Allow this op in DRIVER_OK only for devices that support
changing the address during DRIVER_OK if the device is suspended.

Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Suggested-by: Eugenio Pérez <eperezma@redhat.com>
---
drivers/vhost/vdpa.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 00b4fa8e89f2..6bfa3391935a 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -625,6 +625,29 @@ static long vhost_vdpa_resume(struct vhost_vdpa *v)
return ret;
}

+static bool vhost_vdpa_vq_config_allowed(struct vhost_vdpa *v, unsigned int cmd)
+{
+ struct vdpa_device *vdpa = v->vdpa;
+ const struct vdpa_config_ops *ops = vdpa->config;
+ int feature;
+
+ if (!(ops->get_status(vdpa) & VIRTIO_CONFIG_S_DRIVER_OK))
+ return true;
+
+ if (!v->suspended)
+ return false;
+
+ switch (cmd) {
+ case VHOST_SET_VRING_ADDR:
+ feature = VHOST_BACKEND_F_CHANGEABLE_VQ_ADDR_IN_SUSPEND;
+ break;
+ default:
+ return false;
+ }
+
+ return v->vdev.vqs && vhost_backend_has_feature(v->vdev.vqs[0], feature);
+}
+
static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
void __user *argp)
{
@@ -703,6 +726,9 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,

switch (cmd) {
case VHOST_SET_VRING_ADDR:
+ if (!vhost_vdpa_vq_config_allowed(v, cmd))
+ return -EOPNOTSUPP;
+
if (ops->set_vq_address(vdpa, idx,
(u64)(uintptr_t)vq->desc,
(u64)(uintptr_t)vq->avail,
--
2.43.0