From: Rob Clark <robdclark@xxxxxxxxxxxx>
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 <robdclark@xxxxxxxxxxxx>
---
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.
Alternative idea is to just drop the restriction that blob_flags
be non-zero. I'm ok with either approach.
drivers/gpu/drm/virtio/virtgpu_ioctl.c | 7 ++++++-
include/uapi/drm/virtgpu_drm.h | 1 +
2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index 69f1952f3144..92e1ba6b8078 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -36,7 +36,8 @@
#define VIRTGPU_BLOB_FLAG_USE_MASK (VIRTGPU_BLOB_FLAG_USE_MAPPABLE | \
VIRTGPU_BLOB_FLAG_USE_SHAREABLE | \
- VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE)
+ VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE | \
+ VIRTGPU_BLOB_FLAG_USE_INTERNAL)
static int virtio_gpu_fence_event_create(struct drm_device *dev,
struct drm_file *file,
@@ -662,6 +663,10 @@ static int verify_blob(struct virtio_gpu_device *vgdev,
params->size = rc_blob->size;
params->blob = true;
params->blob_flags = rc_blob->blob_flags;
+
+ /* USE_INTERNAL is local to guest kernel, don't past to host: */
+ params->blob_flags &= ~VIRTGPU_BLOB_FLAG_USE_INTERNAL;
+
return 0;
}
diff --git a/include/uapi/drm/virtgpu_drm.h b/include/uapi/drm/virtgpu_drm.h
index 0512fde5e697..62b7483e5c60 100644
--- a/include/uapi/drm/virtgpu_drm.h
+++ b/include/uapi/drm/virtgpu_drm.h
@@ -163,6 +163,7 @@ struct drm_virtgpu_resource_create_blob {
#define VIRTGPU_BLOB_FLAG_USE_MAPPABLE 0x0001
#define VIRTGPU_BLOB_FLAG_USE_SHAREABLE 0x0002
#define VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE 0x0004
+#define VIRTGPU_BLOB_FLAG_USE_INTERNAL 0x0008 /* not-mappable, not-shareable */
/* zero is invalid blob_mem */
__u32 blob_mem;
__u32 blob_flags;
--
2.34.1
