[PATCH 1/2] drm/virtio: Implement RESOURCE_GET_LAYOUT ioctl

From: Julia Zhang
Date: Fri Nov 10 2023 - 15:31:35 EST


From: Daniel Stone <daniels@xxxxxxxxxxxxx>

This ioctl allows the guest to discover how the guest actually allocated
the underlying buffer, which allows buffers to be used for GL<->Vulkan
interop and through standard window systems. It's also a step towards
properly supporting modifiers in the guest.
---
drivers/gpu/drm/virtio/virtgpu_drv.c | 1 +
drivers/gpu/drm/virtio/virtgpu_drv.h | 16 +++++-
drivers/gpu/drm/virtio/virtgpu_ioctl.c | 71 ++++++++++++++++++++++++++
drivers/gpu/drm/virtio/virtgpu_kms.c | 8 ++-
drivers/gpu/drm/virtio/virtgpu_vq.c | 56 ++++++++++++++++++++
include/uapi/drm/virtgpu_drm.h | 19 +++++++
include/uapi/linux/virtio_gpu.h | 30 +++++++++++
7 files changed, 198 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.c b/drivers/gpu/drm/virtio/virtgpu_drv.c
index 4f7140e27614..1ee09974d4b7 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.c
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.c
@@ -190,6 +190,7 @@ static unsigned int features[] = {
VIRTIO_GPU_F_RESOURCE_BLOB,
VIRTIO_GPU_F_CONTEXT_INIT,
VIRTIO_GPU_F_CONTEXT_FENCE_WAIT,
+ VIRTIO_GPU_F_RESOURCE_QUERY_LAYOUT,
};
static struct virtio_driver virtio_gpu_driver = {
.feature_table = features,
diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
index 7ef4b3df0ada..d6fc0d4ecb7d 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -93,6 +93,15 @@ struct virtio_gpu_object {
bool host3d_blob, guest_blob;
uint32_t blob_mem, blob_flags;

+ atomic_t layout_state;
+ struct {
+ uint64_t offset;
+ uint64_t size;
+ uint32_t stride;
+ } planes[VIRTIO_GPU_RES_MAX_PLANES];
+ uint64_t modifier;
+ uint32_t num_planes;
+
int uuid_state;
uuid_t uuid;

@@ -249,6 +258,7 @@ struct virtio_gpu_device {
bool has_host_visible;
bool has_context_init;
bool has_host_fence_wait;
+ bool has_resource_query_layout;
struct virtio_shm_region host_visible_region;
struct drm_mm host_visible_mm;

@@ -281,7 +291,7 @@ struct virtio_gpu_fpriv {
};

/* virtgpu_ioctl.c */
-#define DRM_VIRTIO_NUM_IOCTLS 12
+#define DRM_VIRTIO_NUM_IOCTLS 13
extern struct drm_ioctl_desc virtio_gpu_ioctls[DRM_VIRTIO_NUM_IOCTLS];
void virtio_gpu_create_context(struct drm_device *dev, struct drm_file *file);

@@ -436,6 +446,10 @@ int virtio_gpu_cmd_status_freezing(struct virtio_gpu_device *vgdev,
void virtio_gpu_cmd_host_wait(struct virtio_gpu_device *vgdev,
uint32_t ctx_id, uint64_t fence_id);

+int
+virtio_gpu_cmd_get_resource_layout(struct virtio_gpu_device *vgdev,
+ struct virtio_gpu_object *bo);
+
/* virtgpu_display.c */
int virtio_gpu_modeset_init(struct virtio_gpu_device *vgdev);
void virtio_gpu_modeset_fini(struct virtio_gpu_device *vgdev);
diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index b6079d2bff69..51d04460d0d8 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -107,6 +107,9 @@ static int virtio_gpu_getparam_ioctl(struct drm_device *dev, void *data,
case VIRTGPU_PARAM_SUPPORTED_CAPSET_IDs:
value = vgdev->capset_id_mask;
break;
+ case VIRTGPU_PARAM_RESOURCE_QUERY_LAYOUT:
+ value = vgdev->has_resource_query_layout ? 1 : 0;
+ break;
default:
return -EINVAL;
}
@@ -676,6 +679,70 @@ static int virtio_gpu_context_init_ioctl(struct drm_device *dev,
return ret;
}

+static int virtio_gpu_resource_query_layout_ioctl(struct drm_device *dev,
+ void *data,
+ struct drm_file *file)
+{
+ struct drm_virtgpu_resource_query_layout *args = data;
+ struct virtio_gpu_device *vgdev = dev->dev_private;
+ struct drm_gem_object *obj;
+ struct virtio_gpu_object *bo;
+ int layout_state;
+ int ret = 0;
+ int i;
+
+ if (!vgdev->has_resource_query_layout) {
+ DRM_ERROR("failing: no RQL on host\n");
+ return -EINVAL;
+ }
+
+ obj = drm_gem_object_lookup(file, args->handle);
+ if (obj == NULL) {
+ DRM_ERROR("invalid handle 0x%x\n", args->handle);
+ return -ENOENT;
+ }
+ bo = gem_to_virtio_gpu_obj(obj);
+
+ layout_state = atomic_read(&bo->layout_state);
+ if (layout_state == STATE_ERR) {
+ ret = -EINVAL;
+ goto out;
+ } else if (layout_state == STATE_OK) {
+ goto valid;
+ }
+
+ ret = virtio_gpu_cmd_get_resource_layout(vgdev, bo);
+ if (ret)
+ goto out;
+
+ ret = wait_event_timeout(vgdev->resp_wq,
+ atomic_read(&bo->layout_state) == STATE_OK,
+ 5 * HZ);
+ if (!ret)
+ goto out;
+
+valid:
+ smp_rmb();
+ WARN_ON(atomic_read(&bo->layout_state) != STATE_OK);
+ args->num_planes = bo->num_planes;
+ args->modifier = bo->modifier;
+ for (i = 0; i < args->num_planes; i++) {
+ args->planes[i].offset = bo->planes[i].offset;
+ args->planes[i].size = bo->planes[i].size;
+ args->planes[i].stride = bo->planes[i].stride;
+ }
+ for (; i < VIRTIO_GPU_MAX_RESOURCE_PLANES; i++) {
+ args->planes[i].offset = 0;
+ args->planes[i].size = 0;
+ args->planes[i].stride = 0;
+ }
+ ret = 0;
+
+out:
+ drm_gem_object_put(obj);
+ return ret;
+}
+
struct drm_ioctl_desc virtio_gpu_ioctls[DRM_VIRTIO_NUM_IOCTLS] = {
DRM_IOCTL_DEF_DRV(VIRTGPU_MAP, virtio_gpu_map_ioctl,
DRM_RENDER_ALLOW),
@@ -715,4 +782,8 @@ struct drm_ioctl_desc virtio_gpu_ioctls[DRM_VIRTIO_NUM_IOCTLS] = {

DRM_IOCTL_DEF_DRV(VIRTGPU_CONTEXT_INIT, virtio_gpu_context_init_ioctl,
DRM_RENDER_ALLOW),
+
+ DRM_IOCTL_DEF_DRV(VIRTGPU_RESOURCE_QUERY_LAYOUT,
+ virtio_gpu_resource_query_layout_ioctl,
+ DRM_RENDER_ALLOW),
};
diff --git a/drivers/gpu/drm/virtio/virtgpu_kms.c b/drivers/gpu/drm/virtio/virtgpu_kms.c
index dd6450179227..fe863bf07298 100644
--- a/drivers/gpu/drm/virtio/virtgpu_kms.c
+++ b/drivers/gpu/drm/virtio/virtgpu_kms.c
@@ -188,6 +188,9 @@ int virtio_gpu_init(struct virtio_device *vdev, struct drm_device *dev)
if (virtio_has_feature(vgdev->vdev, VIRTIO_GPU_F_RESOURCE_BLOB)) {
vgdev->has_resource_blob = true;
}
+ if (virtio_has_feature(vgdev->vdev, VIRTIO_GPU_F_RESOURCE_QUERY_LAYOUT)) {
+ vgdev->has_resource_query_layout = true;
+ }
if (virtio_get_shm_region(vgdev->vdev, &vgdev->host_visible_region,
VIRTIO_GPU_SHM_ID_HOST_VISIBLE)) {
if (!devm_request_mem_region(&vgdev->vdev->dev,
@@ -221,8 +224,9 @@ int virtio_gpu_init(struct virtio_device *vdev, struct drm_device *dev)
vgdev->has_host_visible ? '+' : '-',
vgdev->has_host_fence_wait ? '+' : '-');

- DRM_INFO("features: %ccontext_init\n",
- vgdev->has_context_init ? '+' : '-');
+ DRM_INFO("features: %ccontext_init %cresource_query_layout\n",
+ vgdev->has_context_init ? '+' : '-',
+ vgdev->has_resource_query_layout ? '+' : '-');

ret = virtio_gpu_init_vqs(vdev);
if (ret) {
diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
index 7a4c9e30f847..8d0a2eaec11c 100644
--- a/drivers/gpu/drm/virtio/virtgpu_vq.c
+++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
@@ -1333,3 +1333,59 @@ void virtio_gpu_cmd_host_wait(struct virtio_gpu_device *vgdev,

virtio_gpu_queue_ctrl_buffer(vgdev, vbuf);
}
+
+static void virtio_gpu_cmd_get_resource_layout_cb(struct virtio_gpu_device *vgdev,
+ struct virtio_gpu_vbuffer *vbuf)
+{
+ struct virtio_gpu_resp_resource_layout *resp =
+ (struct virtio_gpu_resp_resource_layout *)vbuf->resp_buf;
+ struct virtio_gpu_object *bo = vbuf->resp_cb_data;
+ int i;
+
+ vbuf->resp_cb_data = NULL;
+
+ if (resp->hdr.type != VIRTIO_GPU_RESP_OK_RESOURCE_LAYOUT) {
+ atomic_set(&bo->layout_state, STATE_ERR);
+ goto out;
+ }
+
+ bo->modifier = le64_to_cpu(resp->modifier);
+ bo->num_planes = le32_to_cpu(resp->num_planes);
+ for (i = 0; i < VIRTIO_GPU_RES_MAX_PLANES; i++) {
+ bo->planes[i].offset = le64_to_cpu(resp->planes[i].offset);
+ bo->planes[i].size = le64_to_cpu(resp->planes[i].size);
+ bo->planes[i].stride = le32_to_cpu(resp->planes[i].stride);
+ }
+ smp_wmb();
+ atomic_set(&bo->layout_state, STATE_OK);
+
+out:
+ drm_gem_object_put(&bo->base.base);
+ wake_up_all(&vgdev->resp_wq);
+}
+
+int virtio_gpu_cmd_get_resource_layout(struct virtio_gpu_device *vgdev,
+ struct virtio_gpu_object *bo)
+{
+ struct virtio_gpu_resource_query_layout *cmd_p;
+ struct virtio_gpu_vbuffer *vbuf;
+ void *resp_buf;
+
+ resp_buf = kzalloc(sizeof(struct virtio_gpu_resp_resource_layout),
+ GFP_KERNEL);
+ if (!resp_buf)
+ return -ENOMEM;
+
+ cmd_p = virtio_gpu_alloc_cmd_resp
+ (vgdev, &virtio_gpu_cmd_get_resource_layout_cb, &vbuf,
+ sizeof(*cmd_p), sizeof(struct virtio_gpu_resp_resource_layout),
+ resp_buf);
+ memset(cmd_p, 0, sizeof(*cmd_p));
+
+ cmd_p->hdr.type = cpu_to_le32(VIRTIO_GPU_CMD_RESOURCE_QUERY_LAYOUT);
+ cmd_p->resource_id = cpu_to_le32(bo->hw_res_handle);
+ drm_gem_object_get(&bo->base.base);
+ vbuf->resp_cb_data = bo;
+ virtio_gpu_queue_ctrl_buffer(vgdev, vbuf);
+ return 0;
+}
diff --git a/include/uapi/drm/virtgpu_drm.h b/include/uapi/drm/virtgpu_drm.h
index ac804cef737c..7ec57d7e261a 100644
--- a/include/uapi/drm/virtgpu_drm.h
+++ b/include/uapi/drm/virtgpu_drm.h
@@ -48,6 +48,7 @@ extern "C" {
#define DRM_VIRTGPU_GET_CAPS 0x09
#define DRM_VIRTGPU_RESOURCE_CREATE_BLOB 0x0a
#define DRM_VIRTGPU_CONTEXT_INIT 0x0b
+#define DRM_VIRTGPU_RESOURCE_QUERY_LAYOUT 0x0c

#define VIRTGPU_EXECBUF_FENCE_FD_IN 0x01
#define VIRTGPU_EXECBUF_FENCE_FD_OUT 0x02
@@ -97,6 +98,7 @@ struct drm_virtgpu_execbuffer {
#define VIRTGPU_PARAM_CROSS_DEVICE 5 /* Cross virtio-device resource sharing */
#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_RESOURCE_QUERY_LAYOUT 8 /* DRM_VIRTGPU_RESOURCE_QUERY_LAYOUT (also needs cap) */

struct drm_virtgpu_getparam {
__u64 param;
@@ -212,6 +214,19 @@ struct drm_virtgpu_context_init {
__u64 ctx_set_params;
};

+#define VIRTIO_GPU_MAX_RESOURCE_PLANES 4
+struct drm_virtgpu_resource_query_layout {
+ __u32 handle;
+ __u32 num_planes;
+ __u64 modifier;
+ struct {
+ __u64 offset;
+ __u64 size;
+ __u32 stride;
+ __u32 padding;
+ } planes[VIRTIO_GPU_MAX_RESOURCE_PLANES];
+};
+
/*
* Event code that's given when VIRTGPU_CONTEXT_PARAM_POLL_RINGS_MASK is in
* effect. The event size is sizeof(drm_event), since there is no additional
@@ -262,6 +277,10 @@ struct drm_virtgpu_context_init {
DRM_IOWR(DRM_COMMAND_BASE + DRM_VIRTGPU_CONTEXT_INIT, \
struct drm_virtgpu_context_init)

+#define DRM_IOCTL_VIRTGPU_RESOURCE_QUERY_LAYOUT \
+ DRM_IOWR(DRM_COMMAND_BASE + DRM_VIRTGPU_RESOURCE_QUERY_LAYOUT, \
+ struct drm_virtgpu_resource_query_layout)
+
#if defined(__cplusplus)
}
#endif
diff --git a/include/uapi/linux/virtio_gpu.h b/include/uapi/linux/virtio_gpu.h
index c9bf921303cc..c7b22861af69 100644
--- a/include/uapi/linux/virtio_gpu.h
+++ b/include/uapi/linux/virtio_gpu.h
@@ -70,6 +70,11 @@
*/
#define VIRTIO_GPU_F_CONTEXT_FENCE_WAIT 5

+/*
+ * VIRTIO_GPU_CMD_RESOURCE_QUERY_LAYOUT
+ */
+#define VIRTIO_GPU_F_RESOURCE_QUERY_LAYOUT 6
+
enum virtio_gpu_ctrl_type {
VIRTIO_GPU_UNDEFINED = 0,

@@ -101,6 +106,7 @@ enum virtio_gpu_ctrl_type {
VIRTIO_GPU_CMD_RESOURCE_MAP_BLOB,
VIRTIO_GPU_CMD_RESOURCE_UNMAP_BLOB,
VIRTIO_GPU_CMD_WAIT_FENCE,
+ VIRTIO_GPU_CMD_RESOURCE_QUERY_LAYOUT,

/* cursor commands */
VIRTIO_GPU_CMD_UPDATE_CURSOR = 0x0300,
@@ -114,6 +120,7 @@ enum virtio_gpu_ctrl_type {
VIRTIO_GPU_RESP_OK_EDID,
VIRTIO_GPU_RESP_OK_RESOURCE_UUID,
VIRTIO_GPU_RESP_OK_MAP_INFO,
+ VIRTIO_GPU_RESP_OK_RESOURCE_LAYOUT,

/* error responses */
VIRTIO_GPU_RESP_ERR_UNSPEC = 0x1200,
@@ -474,4 +481,27 @@ struct virtio_gpu_cmd_host_wait {
__le64 fence_id;
};

+/* VIRTIO_GPU_CMD_RESOURCE_QUERY_LAYOUT */
+struct virtio_gpu_resource_query_layout {
+ struct virtio_gpu_ctrl_hdr hdr;
+ __le32 resource_id;
+ __le32 padding;
+};
+
+
+/* VIRTIO_GPU_RESP_OK_RESOURCE_LAYOUT */
+#define VIRTIO_GPU_RES_MAX_PLANES 4
+struct virtio_gpu_resp_resource_layout {
+ struct virtio_gpu_ctrl_hdr hdr;
+ __le64 modifier;
+ __le32 num_planes;
+ __le32 padding;
+ struct virtio_gpu_resource_plane {
+ __le64 offset;
+ __le64 size;
+ __le32 stride;
+ __le32 padding;
+ } planes[VIRTIO_GPU_RES_MAX_PLANES];
+};
+
#endif
--
2.34.1