[PATCH] drm/virtio: do not enforce blob_alignment in cross-domain contexts

[PATCH] drm/virtio: do not enforce blob_alignment in cross-domain contexts

[Val Packett]

VIRTIO_GPU_F_BLOB_ALIGNMENT is designed for GPU rendering context types,
however VIRTIO_GPU_CAPSET_CROSS_DOMAIN is not one of those. Resources
created under cross-domain contexts are arbitrary shared system memory
files, which includes unusual things like Wayland keymaps received
from the host compositor. Do not enforce alignment requirements there.

Fixes: 47248e0d8264 ("drm/virtio: honor blob_alignment requirements")
Signed-off-by: Val Packett <val@invisiblethingslab.com>
---

That took its time to be discovered since devices didn't start offering
blob_alignment until now e.g. https://github.com/libkrun/libkrun/pull/886

It would also be fine to just revert 47248e0d8264 but I guess this way
no one would question why "there's an alignment and we aren't enforcing it"..

Thanks,
~val

---
 drivers/gpu/drm/virtio/virtgpu_ioctl.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index 01a5f17cb22b..d493f04b9993 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -551,6 +551,8 @@ static int verify_blob(struct virtio_gpu_device *vgdev,
 	params->blob_hints = rc_blob->blob_hints;
 
 	if (vgdev->has_blob_alignment &&
+	    (vfpriv->context_init & VIRTIO_GPU_CONTEXT_INIT_CAPSET_ID_MASK) !=
+	    VIRTIO_GPU_CAPSET_CROSS_DOMAIN &&
 	    !IS_ALIGNED(params->size, vgdev->blob_alignment))
 		return -EINVAL;
 
-- 
2.55.0