| Message ID | 20250214-virtio-shm-page-size-v2-5-aa1619e6908b@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | virtio: obtain SHM page size from device | expand |
On 2/14/25 18:16, Sergio Lopez wrote: > diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c > index c33c057365f85a2ace536f91655c903036827312..4b49635b4fe1d4256f219823341cef8e5fa8f029 100644 > --- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c > +++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c > @@ -117,6 +117,11 @@ static int virtio_gpu_getparam_ioctl(struct drm_device *dev, void *data, > case VIRTGPU_PARAM_EXPLICIT_DEBUG_NAME: > value = vgdev->has_context_init ? 1 : 0; > break; > + case VIRTGPU_PARAM_HOST_SHM_PAGE_SIZE: > + if (!vgdev->has_host_visible) > + return -EINVAL; Nit: virtio_gpu_getparam_ioctl() returns EINVAL for unsupported params. While this is a supported param, but there is no hostmem available. Hence, should a different error code, maybe ENOENT or ENXIO.
Dmitry Osipenko <dmitry.osipenko@collabora.com> writes: > On 2/14/25 18:16, Sergio Lopez wrote: >> diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c >> index c33c057365f85a2ace536f91655c903036827312..4b49635b4fe1d4256f219823341cef8e5fa8f029 100644 >> --- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c >> +++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c >> @@ -117,6 +117,11 @@ static int virtio_gpu_getparam_ioctl(struct drm_device *dev, void *data, >> case VIRTGPU_PARAM_EXPLICIT_DEBUG_NAME: >> value = vgdev->has_context_init ? 1 : 0; >> break; >> + case VIRTGPU_PARAM_HOST_SHM_PAGE_SIZE: >> + if (!vgdev->has_host_visible) >> + return -EINVAL; > > Nit: virtio_gpu_getparam_ioctl() returns EINVAL for unsupported params. > While this is a supported param, but there is no hostmem available. > Hence, should a different error code, maybe ENOENT or ENXIO. Good point. I'll update it to return ENOENT in v3. Thanks, Sergio.
diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c index c33c057365f85a2ace536f91655c903036827312..4b49635b4fe1d4256f219823341cef8e5fa8f029 100644 --- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c +++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c @@ -117,6 +117,11 @@ static int virtio_gpu_getparam_ioctl(struct drm_device *dev, void *data, case VIRTGPU_PARAM_EXPLICIT_DEBUG_NAME: value = vgdev->has_context_init ? 1 : 0; break; + case VIRTGPU_PARAM_HOST_SHM_PAGE_SIZE: + if (!vgdev->has_host_visible) + return -EINVAL; + value = vgdev->host_visible_region.page_size; + break; default: return -EINVAL; } diff --git a/include/uapi/drm/virtgpu_drm.h b/include/uapi/drm/virtgpu_drm.h index c2ce71987e9bb816d13a300679336cb756f1cbcf..72db6b3339e0dcaf550acbf5ac4381a6e5c2216d 100644 --- a/include/uapi/drm/virtgpu_drm.h +++ b/include/uapi/drm/virtgpu_drm.h @@ -98,6 +98,7 @@ struct drm_virtgpu_execbuffer { #define VIRTGPU_PARAM_CONTEXT_INIT 6 /* DRM_VIRTGPU_CONTEXT_INIT */ #define VIRTGPU_PARAM_SUPPORTED_CAPSET_IDs 7 /* Bitmask of supported capability set ids */ #define VIRTGPU_PARAM_EXPLICIT_DEBUG_NAME 8 /* Ability to set debug name from userspace */ +#define VIRTGPU_PARAM_HOST_SHM_PAGE_SIZE 9 /* Host SHM page size, with format PAGE_SIZE >> 12 */ struct drm_virtgpu_getparam { __u64 param;
Add VIRTGPU_PARAM_HOST_SHM_PAGE_SIZE as a param that can be read with VIRTGPU_GETPARAM by userspace applications running in the guest to obtain the host's page size and find out the right alignment to be used in shared memory allocations. Signed-off-by: Sergio Lopez <slp@redhat.com> --- drivers/gpu/drm/virtio/virtgpu_ioctl.c | 5 +++++ include/uapi/drm/virtgpu_drm.h | 1 + 2 files changed, 6 insertions(+)