On Thu, Jul 16, 2026 at 3:25 PM Dorinda Bassey <[email protected]> wrote:
>
> From: Matej Hrica <[email protected]>
>
> Add a 'hostmem' property to the vhost-user-gpu which enables the shared
> memory in the parent object.
>
> Register a container MR in the shmem_list for SHMEM_MAP/UNMAP
> operations. A container MR is used so that SHMEM_MAP FD-backed
> subregions each get their own KVM memory slot with the correct
> backing fd.
>
> Signed-off-by: Matej Hrica <[email protected]>
> Signed-off-by: Dorinda Bassey <[email protected]>
> ---
> hw/display/vhost-user-gpu.c | 16 ++++++++++++++++
> 1 file changed, 16 insertions(+)
>
> diff --git a/hw/display/vhost-user-gpu.c b/hw/display/vhost-user-gpu.c
> index 06549c98e07..7e4580aa895 100644
> --- a/hw/display/vhost-user-gpu.c
> +++ b/hw/display/vhost-user-gpu.c
> @@ -655,6 +655,21 @@ vhost_user_gpu_device_realize(DeviceState *qdev, Error
> **errp)
> }
>
> g->vhost_gpu_fd = -1;
> +
> + /*
> + * If shared memory is enabled, register the hostmem region for
> + * SHMEM_MAP/UNMAP operations.
> + */
> + if (virtio_gpu_hostmem_enabled(g->parent_obj.conf)) {
> + VirtioSharedMemory *shmem = g_new0(VirtioSharedMemory, 1);
> + shmem->shmid = VIRTIO_GPU_SHM_ID_HOST_VISIBLE;
> + memory_region_init(&shmem->mr, OBJECT(vdev),
> + "vhost-user-gpu-shmem",
> + g->parent_obj.conf.hostmem);
> + memory_region_add_subregion(&g->parent_obj.hostmem, 0, &shmem->mr);
> + QTAILQ_INIT(&shmem->mmaps);
> + QSIMPLEQ_INSERT_TAIL(&vdev->shmem_list, shmem, entry);
> + }
Why not just use virtio_new_shmem_region()?
> }
>
> static struct vhost_dev *vhost_user_gpu_get_vhost(VirtIODevice *vdev)
> @@ -665,6 +680,7 @@ static struct vhost_dev
> *vhost_user_gpu_get_vhost(VirtIODevice *vdev)
>
> static const Property vhost_user_gpu_properties[] = {
> VIRTIO_GPU_BASE_PROPERTIES(VhostUserGPU, parent_obj.conf),
> + DEFINE_PROP_SIZE("hostmem", VhostUserGPU, parent_obj.conf.hostmem, 0),
> };
>
> static void
> --
> 2.52.0
>
