Stefano Garzarella
2023-Jun-05 11:06 UTC
[PATCH] vhost-vdpa: filter VIRTIO_F_RING_PACKED feature
vhost-vdpa IOCTLs (eg. VHOST_GET_VRING_BASE, VHOST_SET_VRING_BASE)
don't support packed virtqueue well yet, so let's filter the
VIRTIO_F_RING_PACKED feature for now in vhost_vdpa_get_features().
This way, even if the device supports it, we don't risk it being
negotiated, then the VMM is unable to set the vring state properly.
Fixes: 4c8cf31885f6 ("vhost: introduce vDPA-based backend")
Cc: stable at vger.kernel.org
Signed-off-by: Stefano Garzarella <sgarzare at redhat.com>
---
Notes:
This patch should be applied before the "[PATCH v2 0/3] vhost_vdpa:
better PACKED support" series [1] and backported in stable branches.
We can revert it when we are sure that everything is working with
packed virtqueues.
Thanks,
Stefano
[1]
https://lore.kernel.org/virtualization/20230424225031.18947-1-shannon.nelson at
amd.com/
drivers/vhost/vdpa.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 8c1aefc865f0..ac2152135b23 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -397,6 +397,12 @@ static long vhost_vdpa_get_features(struct vhost_vdpa *v,
u64 __user *featurep)
features = ops->get_device_features(vdpa);
+ /*
+ * IOCTLs (eg. VHOST_GET_VRING_BASE, VHOST_SET_VRING_BASE) don't support
+ * packed virtqueue well yet, so let's filter the feature for now.
+ */
+ features &= ~BIT_ULL(VIRTIO_F_RING_PACKED);
+
if (copy_to_user(featurep, &features, sizeof(features)))
return -EFAULT;
base-commit: 9561de3a55bed6bdd44a12820ba81ec416e705a7
--
2.40.1
Michael S. Tsirkin
2023-Jun-05 12:41 UTC
[PATCH] vhost-vdpa: filter VIRTIO_F_RING_PACKED feature
On Mon, Jun 05, 2023 at 01:06:44PM +0200, Stefano Garzarella wrote:> vhost-vdpa IOCTLs (eg. VHOST_GET_VRING_BASE, VHOST_SET_VRING_BASE) > don't support packed virtqueue well yet, so let's filter the > VIRTIO_F_RING_PACKED feature for now in vhost_vdpa_get_features(). > > This way, even if the device supports it, we don't risk it being > negotiated, then the VMM is unable to set the vring state properly. > > Fixes: 4c8cf31885f6 ("vhost: introduce vDPA-based backend") > Cc: stable at vger.kernel.org > Signed-off-by: Stefano Garzarella <sgarzare at redhat.com> > --- > > Notes: > This patch should be applied before the "[PATCH v2 0/3] vhost_vdpa: > better PACKED support" series [1] and backported in stable branches. > > We can revert it when we are sure that everything is working with > packed virtqueues. > > Thanks, > Stefano > > [1] https://lore.kernel.org/virtualization/20230424225031.18947-1-shannon.nelson at amd.com/I'm a bit lost here. So why am I merging "better PACKED support" then? Does this patch make them a NOP?> drivers/vhost/vdpa.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c > index 8c1aefc865f0..ac2152135b23 100644 > --- a/drivers/vhost/vdpa.c > +++ b/drivers/vhost/vdpa.c > @@ -397,6 +397,12 @@ static long vhost_vdpa_get_features(struct vhost_vdpa *v, u64 __user *featurep) > > features = ops->get_device_features(vdpa); > > + /* > + * IOCTLs (eg. VHOST_GET_VRING_BASE, VHOST_SET_VRING_BASE) don't support > + * packed virtqueue well yet, so let's filter the feature for now. > + */ > + features &= ~BIT_ULL(VIRTIO_F_RING_PACKED); > + > if (copy_to_user(featurep, &features, sizeof(features))) > return -EFAULT; > > > base-commit: 9561de3a55bed6bdd44a12820ba81ec416e705a7 > -- > 2.40.1
Michael S. Tsirkin
2023-Jun-22 11:37 UTC
[PATCH] vhost-vdpa: filter VIRTIO_F_RING_PACKED feature
On Mon, Jun 05, 2023 at 01:06:44PM +0200, Stefano Garzarella wrote:> vhost-vdpa IOCTLs (eg. VHOST_GET_VRING_BASE, VHOST_SET_VRING_BASE) > don't support packed virtqueue well yet, so let's filter the > VIRTIO_F_RING_PACKED feature for now in vhost_vdpa_get_features(). > > This way, even if the device supports it, we don't risk it being > negotiated, then the VMM is unable to set the vring state properly. > > Fixes: 4c8cf31885f6 ("vhost: introduce vDPA-based backend") > Cc: stable at vger.kernel.org > Signed-off-by: Stefano Garzarella <sgarzare at redhat.com>OK so for now I dropped this, we have a better fix upstream.> --- > > Notes: > This patch should be applied before the "[PATCH v2 0/3] vhost_vdpa: > better PACKED support" series [1] and backported in stable branches. > > We can revert it when we are sure that everything is working with > packed virtqueues. > > Thanks, > Stefano > > [1] https://lore.kernel.org/virtualization/20230424225031.18947-1-shannon.nelson at amd.com/ > > drivers/vhost/vdpa.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c > index 8c1aefc865f0..ac2152135b23 100644 > --- a/drivers/vhost/vdpa.c > +++ b/drivers/vhost/vdpa.c > @@ -397,6 +397,12 @@ static long vhost_vdpa_get_features(struct vhost_vdpa *v, u64 __user *featurep) > > features = ops->get_device_features(vdpa); > > + /* > + * IOCTLs (eg. VHOST_GET_VRING_BASE, VHOST_SET_VRING_BASE) don't support > + * packed virtqueue well yet, so let's filter the feature for now. > + */ > + features &= ~BIT_ULL(VIRTIO_F_RING_PACKED); > + > if (copy_to_user(featurep, &features, sizeof(features))) > return -EFAULT; > > > base-commit: 9561de3a55bed6bdd44a12820ba81ec416e705a7 > -- > 2.40.1