2022-02-19 18:50:36

by Rob Clark

Subject: [PATCH] drm/virtio: Remove restriction of non-zero blob_flags

From: Rob Clark <[email protected]>

With native userspace drivers in guest, a lot of GEM objects need to be
neither shared nor mappable. And in fact making everything mappable
and/or sharable results in unreasonably high fd usage in host VMM.

Signed-off-by: Rob Clark <[email protected]>
---
This is for a thing I'm working on, a new virtgpu context type that
allows for running native userspace driver in the guest, with a
thin shim in the host VMM. In this case, the guest has a lot of
GEM buffer objects which need to be neither shared nor mappable.

This supersedes https://patchwork.freedesktop.org/patch/475127/

drivers/gpu/drm/virtio/virtgpu_ioctl.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index 69f1952f3144..3a8078f2ee27 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -617,8 +617,7 @@ static int verify_blob(struct virtio_gpu_device *vgdev,
if (!vgdev->has_resource_blob)
return -EINVAL;

- if ((rc_blob->blob_flags & ~VIRTGPU_BLOB_FLAG_USE_MASK) ||
- !rc_blob->blob_flags)
+ if (rc_blob->blob_flags & ~VIRTGPU_BLOB_FLAG_USE_MASK)
return -EINVAL;

if (rc_blob->blob_flags & VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE) {
--
2.34.1

2022-02-23 06:51:54

by Chia-I Wu

Subject: Re: [PATCH] drm/virtio: Remove restriction of non-zero blob_flags

On Sat, Feb 19, 2022 at 9:02 AM Rob Clark <[email protected]> wrote:
>
> From: Rob Clark <[email protected]>
>
> With native userspace drivers in guest, a lot of GEM objects need to be
> neither shared nor mappable. And in fact making everything mappable
> and/or sharable results in unreasonably high fd usage in host VMM.
>
> Signed-off-by: Rob Clark <[email protected]>
Reviewed-by: Chia-I Wu <[email protected]>