Add support for UUID-based resource sharing mechanism to virtgpu. This
implements the new virtgpu commands and hooks them up to dma-buf's
get_uuid callback.
Signed-off-by: David Stevens <[email protected]>
---
drivers/gpu/drm/virtio/virtgpu_drv.c | 3 ++
drivers/gpu/drm/virtio/virtgpu_drv.h | 18 +++++++++
drivers/gpu/drm/virtio/virtgpu_kms.c | 4 ++
drivers/gpu/drm/virtio/virtgpu_prime.c | 41 +++++++++++++++++--
drivers/gpu/drm/virtio/virtgpu_vq.c | 55 ++++++++++++++++++++++++++
5 files changed, 118 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.c b/drivers/gpu/drm/virtio/virtgpu_drv.c
index ab4bed78e656..776e6667042e 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.c
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.c
@@ -165,6 +165,7 @@ static unsigned int features[] = {
VIRTIO_GPU_F_VIRGL,
#endif
VIRTIO_GPU_F_EDID,
+ VIRTIO_GPU_F_RESOURCE_UUID,
};
static struct virtio_driver virtio_gpu_driver = {
.feature_table = features,
@@ -202,7 +203,9 @@ static struct drm_driver driver = {
.prime_handle_to_fd = drm_gem_prime_handle_to_fd,
.prime_fd_to_handle = drm_gem_prime_fd_to_handle,
.gem_prime_mmap = drm_gem_prime_mmap,
+ .gem_prime_export = virtgpu_gem_prime_export,
.gem_prime_import_sg_table = virtgpu_gem_prime_import_sg_table,
+ .gem_prime_get_uuid = virtgpu_gem_prime_get_uuid,
.gem_create_object = virtio_gpu_create_object,
.fops = &virtio_gpu_driver_fops,
diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
index af9403e1cf78..fab65f0f5a4d 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -49,6 +49,10 @@
#define DRIVER_MINOR 1
#define DRIVER_PATCHLEVEL 0
+#define UUID_INITIALIZING 0
+#define UUID_INITIALIZED 1
+#define UUID_INITIALIZATION_FAILED 2
+
struct virtio_gpu_object_params {
uint32_t format;
uint32_t width;
@@ -75,6 +79,9 @@ struct virtio_gpu_object {
bool dumb;
bool created;
+
+ int uuid_state;
+ uuid_t uuid;
};
#define gem_to_virtio_gpu_obj(gobj) \
container_of((gobj), struct virtio_gpu_object, base.base)
@@ -196,6 +203,7 @@ struct virtio_gpu_device {
bool has_virgl_3d;
bool has_edid;
bool has_indirect;
+ bool has_resource_assign_uuid;
struct work_struct config_changed_work;
@@ -206,6 +214,8 @@ struct virtio_gpu_device {
struct virtio_gpu_drv_capset *capsets;
uint32_t num_capsets;
struct list_head cap_cache;
+
+ spinlock_t resource_export_lock;
};
struct virtio_gpu_fpriv {
@@ -338,6 +348,10 @@ void virtio_gpu_dequeue_fence_func(struct work_struct *work);
void virtio_gpu_disable_notify(struct virtio_gpu_device *vgdev);
void virtio_gpu_enable_notify(struct virtio_gpu_device *vgdev);
+int
+virtio_gpu_cmd_resource_assign_uuid(struct virtio_gpu_device *vgdev,
+ struct virtio_gpu_object_array *objs);
+
/* virtio_gpu_display.c */
void virtio_gpu_modeset_init(struct virtio_gpu_device *vgdev);
void virtio_gpu_modeset_fini(struct virtio_gpu_device *vgdev);
@@ -366,6 +380,10 @@ int virtio_gpu_object_create(struct virtio_gpu_device *vgdev,
struct virtio_gpu_object **bo_ptr,
struct virtio_gpu_fence *fence);
/* virtgpu_prime.c */
+struct dma_buf *virtgpu_gem_prime_export(struct drm_gem_object *obj,
+ int flags);
+int virtgpu_gem_prime_get_uuid(struct drm_gem_object *obj,
+ uuid_t *uuid);
struct drm_gem_object *virtgpu_gem_prime_import_sg_table(
struct drm_device *dev, struct dma_buf_attachment *attach,
struct sg_table *sgt);
diff --git a/drivers/gpu/drm/virtio/virtgpu_kms.c b/drivers/gpu/drm/virtio/virtgpu_kms.c
index 4009c2f97d08..5a2aeb6d2f35 100644
--- a/drivers/gpu/drm/virtio/virtgpu_kms.c
+++ b/drivers/gpu/drm/virtio/virtgpu_kms.c
@@ -134,6 +134,7 @@ int virtio_gpu_init(struct drm_device *dev)
vgdev->dev = dev->dev;
spin_lock_init(&vgdev->display_info_lock);
+ spin_lock_init(&vgdev->resource_export_lock);
ida_init(&vgdev->ctx_id_ida);
ida_init(&vgdev->resource_ida);
init_waitqueue_head(&vgdev->resp_wq);
@@ -162,6 +163,9 @@ int virtio_gpu_init(struct drm_device *dev)
if (virtio_has_feature(vgdev->vdev, VIRTIO_RING_F_INDIRECT_DESC)) {
vgdev->has_indirect = true;
}
+ if (virtio_has_feature(vgdev->vdev, VIRTIO_GPU_F_RESOURCE_UUID)) {
+ vgdev->has_resource_assign_uuid = true;
+ }
DRM_INFO("features: %cvirgl %cedid\n",
vgdev->has_virgl_3d ? '+' : '-',
diff --git a/drivers/gpu/drm/virtio/virtgpu_prime.c b/drivers/gpu/drm/virtio/virtgpu_prime.c
index 050d24c39a8f..7c6357f59877 100644
--- a/drivers/gpu/drm/virtio/virtgpu_prime.c
+++ b/drivers/gpu/drm/virtio/virtgpu_prime.c
@@ -26,9 +26,44 @@
#include "virtgpu_drv.h"
-/* Empty Implementations as there should not be any other driver for a virtual
- * device that might share buffers with virtgpu
- */
+int virtgpu_gem_prime_get_uuid(struct drm_gem_object *obj,
+ uuid_t *uuid)
+{
+ struct virtio_gpu_object *bo = gem_to_virtio_gpu_obj(obj);
+ struct virtio_gpu_device *vgdev = obj->dev->dev_private;
+
+ wait_event(vgdev->resp_wq, bo->uuid_state != UUID_INITIALIZING);
+ if (bo->uuid_state != UUID_INITIALIZED)
+ return -ENODEV;
+
+ uuid_copy(uuid, &bo->uuid);
+
+ return 0;
+}
+
+struct dma_buf *virtgpu_gem_prime_export(struct drm_gem_object *obj,
+ int flags)
+{
+ struct virtio_gpu_object *bo = gem_to_virtio_gpu_obj(obj);
+ struct virtio_gpu_device *vgdev = obj->dev->dev_private;
+ struct virtio_gpu_object_array *objs;
+ int ret = 0;
+
+ if (vgdev->has_resource_assign_uuid) {
+ objs = virtio_gpu_array_alloc(1);
+ if (!objs)
+ return ERR_PTR(-ENOMEM);
+ virtio_gpu_array_add_obj(objs, &bo->base.base);
+
+ ret = virtio_gpu_cmd_resource_assign_uuid(vgdev, objs);
+ if (ret)
+ return ERR_PTR(ret);
+ } else {
+ bo->uuid_state = UUID_INITIALIZATION_FAILED;
+ }
+
+ return drm_gem_prime_export(obj, flags);
+}
struct drm_gem_object *virtgpu_gem_prime_import_sg_table(
struct drm_device *dev, struct dma_buf_attachment *attach,
diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
index cfe9c54f87a3..b968eaa46bb0 100644
--- a/drivers/gpu/drm/virtio/virtgpu_vq.c
+++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
@@ -1111,3 +1111,58 @@ void virtio_gpu_cursor_ping(struct virtio_gpu_device *vgdev,
memcpy(cur_p, &output->cursor, sizeof(output->cursor));
virtio_gpu_queue_cursor(vgdev, vbuf);
}
+
+static void virtio_gpu_cmd_resource_uuid_cb(struct virtio_gpu_device *vgdev,
+ struct virtio_gpu_vbuffer *vbuf)
+{
+ struct virtio_gpu_object *obj =
+ gem_to_virtio_gpu_obj(vbuf->objs->objs[0]);
+ struct virtio_gpu_resp_resource_uuid *resp =
+ (struct virtio_gpu_resp_resource_uuid *)vbuf->resp_buf;
+ uint32_t resp_type = le32_to_cpu(resp->hdr.type);
+
+ spin_lock(&vgdev->resource_export_lock);
+ WARN_ON(obj->uuid_state != UUID_INITIALIZING);
+
+ if (resp_type == VIRTIO_GPU_RESP_OK_RESOURCE_UUID &&
+ obj->uuid_state == UUID_INITIALIZING) {
+ memcpy(&obj->uuid.b, resp->uuid, sizeof(obj->uuid.b));
+ obj->uuid_state = UUID_INITIALIZED;
+ } else {
+ obj->uuid_state = UUID_INITIALIZATION_FAILED;
+ }
+ spin_unlock(&vgdev->resource_export_lock);
+
+ wake_up_all(&vgdev->resp_wq);
+}
+
+int
+virtio_gpu_cmd_resource_assign_uuid(struct virtio_gpu_device *vgdev,
+ struct virtio_gpu_object_array *objs)
+{
+ struct virtio_gpu_object *bo = gem_to_virtio_gpu_obj(objs->objs[0]);
+ struct virtio_gpu_resource_assign_uuid *cmd_p;
+ struct virtio_gpu_vbuffer *vbuf;
+ struct virtio_gpu_resp_resource_uuid *resp_buf;
+
+ resp_buf = kzalloc(sizeof(*resp_buf), GFP_KERNEL);
+ if (!resp_buf) {
+ spin_lock(&vgdev->resource_export_lock);
+ bo->uuid_state = UUID_INITIALIZATION_FAILED;
+ spin_unlock(&vgdev->resource_export_lock);
+ virtio_gpu_array_put_free(objs);
+ return -ENOMEM;
+ }
+
+ cmd_p = virtio_gpu_alloc_cmd_resp(vgdev,
+ virtio_gpu_cmd_resource_uuid_cb, &vbuf, sizeof(*cmd_p),
+ sizeof(struct virtio_gpu_resp_resource_uuid), resp_buf);
+ memset(cmd_p, 0, sizeof(*cmd_p));
+
+ cmd_p->hdr.type = cpu_to_le32(VIRTIO_GPU_CMD_RESOURCE_ASSIGN_UUID);
+ cmd_p->resource_id = cpu_to_le32(bo->hw_res_handle);
+
+ vbuf->objs = objs;
+ virtio_gpu_queue_ctrl_buffer(vgdev, vbuf);
+ return 0;
+}
--
2.25.1.481.gfbce0eb801-goog
On Wed, Mar 11, 2020 at 08:20:04PM +0900, David Stevens wrote:
> Add support for UUID-based resource sharing mechanism to virtgpu. This
> implements the new virtgpu commands and hooks them up to dma-buf's
> get_uuid callback.
>
> Signed-off-by: David Stevens <[email protected]>
> ---
> drivers/gpu/drm/virtio/virtgpu_drv.c | 3 ++
> drivers/gpu/drm/virtio/virtgpu_drv.h | 18 +++++++++
> drivers/gpu/drm/virtio/virtgpu_kms.c | 4 ++
> drivers/gpu/drm/virtio/virtgpu_prime.c | 41 +++++++++++++++++--
> drivers/gpu/drm/virtio/virtgpu_vq.c | 55 ++++++++++++++++++++++++++
> 5 files changed, 118 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.c b/drivers/gpu/drm/virtio/virtgpu_drv.c
> index ab4bed78e656..776e6667042e 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_drv.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_drv.c
> @@ -165,6 +165,7 @@ static unsigned int features[] = {
> VIRTIO_GPU_F_VIRGL,
> #endif
> VIRTIO_GPU_F_EDID,
> + VIRTIO_GPU_F_RESOURCE_UUID,
> };
> static struct virtio_driver virtio_gpu_driver = {
> .feature_table = features,
> @@ -202,7 +203,9 @@ static struct drm_driver driver = {
> .prime_handle_to_fd = drm_gem_prime_handle_to_fd,
> .prime_fd_to_handle = drm_gem_prime_fd_to_handle,
> .gem_prime_mmap = drm_gem_prime_mmap,
> + .gem_prime_export = virtgpu_gem_prime_export,
> .gem_prime_import_sg_table = virtgpu_gem_prime_import_sg_table,
> + .gem_prime_get_uuid = virtgpu_gem_prime_get_uuid,
>
> .gem_create_object = virtio_gpu_create_object,
> .fops = &virtio_gpu_driver_fops,
> diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
> index af9403e1cf78..fab65f0f5a4d 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_drv.h
> +++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
> @@ -49,6 +49,10 @@
> #define DRIVER_MINOR 1
> #define DRIVER_PATCHLEVEL 0
>
> +#define UUID_INITIALIZING 0
> +#define UUID_INITIALIZED 1
> +#define UUID_INITIALIZATION_FAILED 2
> +
> struct virtio_gpu_object_params {
> uint32_t format;
> uint32_t width;
> @@ -75,6 +79,9 @@ struct virtio_gpu_object {
>
> bool dumb;
> bool created;
> +
> + int uuid_state;
> + uuid_t uuid;
> };
> #define gem_to_virtio_gpu_obj(gobj) \
> container_of((gobj), struct virtio_gpu_object, base.base)
> @@ -196,6 +203,7 @@ struct virtio_gpu_device {
> bool has_virgl_3d;
> bool has_edid;
> bool has_indirect;
> + bool has_resource_assign_uuid;
>
> struct work_struct config_changed_work;
>
> @@ -206,6 +214,8 @@ struct virtio_gpu_device {
> struct virtio_gpu_drv_capset *capsets;
> uint32_t num_capsets;
> struct list_head cap_cache;
> +
> + spinlock_t resource_export_lock;
> };
>
> struct virtio_gpu_fpriv {
> @@ -338,6 +348,10 @@ void virtio_gpu_dequeue_fence_func(struct work_struct *work);
> void virtio_gpu_disable_notify(struct virtio_gpu_device *vgdev);
> void virtio_gpu_enable_notify(struct virtio_gpu_device *vgdev);
>
> +int
> +virtio_gpu_cmd_resource_assign_uuid(struct virtio_gpu_device *vgdev,
> + struct virtio_gpu_object_array *objs);
> +
> /* virtio_gpu_display.c */
> void virtio_gpu_modeset_init(struct virtio_gpu_device *vgdev);
> void virtio_gpu_modeset_fini(struct virtio_gpu_device *vgdev);
> @@ -366,6 +380,10 @@ int virtio_gpu_object_create(struct virtio_gpu_device *vgdev,
> struct virtio_gpu_object **bo_ptr,
> struct virtio_gpu_fence *fence);
> /* virtgpu_prime.c */
> +struct dma_buf *virtgpu_gem_prime_export(struct drm_gem_object *obj,
> + int flags);
> +int virtgpu_gem_prime_get_uuid(struct drm_gem_object *obj,
> + uuid_t *uuid);
> struct drm_gem_object *virtgpu_gem_prime_import_sg_table(
> struct drm_device *dev, struct dma_buf_attachment *attach,
> struct sg_table *sgt);
> diff --git a/drivers/gpu/drm/virtio/virtgpu_kms.c b/drivers/gpu/drm/virtio/virtgpu_kms.c
> index 4009c2f97d08..5a2aeb6d2f35 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_kms.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_kms.c
> @@ -134,6 +134,7 @@ int virtio_gpu_init(struct drm_device *dev)
> vgdev->dev = dev->dev;
>
> spin_lock_init(&vgdev->display_info_lock);
> + spin_lock_init(&vgdev->resource_export_lock);
> ida_init(&vgdev->ctx_id_ida);
> ida_init(&vgdev->resource_ida);
> init_waitqueue_head(&vgdev->resp_wq);
> @@ -162,6 +163,9 @@ int virtio_gpu_init(struct drm_device *dev)
> if (virtio_has_feature(vgdev->vdev, VIRTIO_RING_F_INDIRECT_DESC)) {
> vgdev->has_indirect = true;
> }
> + if (virtio_has_feature(vgdev->vdev, VIRTIO_GPU_F_RESOURCE_UUID)) {
> + vgdev->has_resource_assign_uuid = true;
> + }
Just a question: this relies on DMA bufs so I assume it is
not really assumed to work when DMA API is bypassed, right?
Rather than worry what does it mean, how about just
disabling this feature without PLATFORM_DMA for now?
>
> DRM_INFO("features: %cvirgl %cedid\n",
> vgdev->has_virgl_3d ? '+' : '-',
> diff --git a/drivers/gpu/drm/virtio/virtgpu_prime.c b/drivers/gpu/drm/virtio/virtgpu_prime.c
> index 050d24c39a8f..7c6357f59877 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_prime.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_prime.c
> @@ -26,9 +26,44 @@
>
> #include "virtgpu_drv.h"
>
> -/* Empty Implementations as there should not be any other driver for a virtual
> - * device that might share buffers with virtgpu
> - */
> +int virtgpu_gem_prime_get_uuid(struct drm_gem_object *obj,
> + uuid_t *uuid)
> +{
> + struct virtio_gpu_object *bo = gem_to_virtio_gpu_obj(obj);
> + struct virtio_gpu_device *vgdev = obj->dev->dev_private;
> +
> + wait_event(vgdev->resp_wq, bo->uuid_state != UUID_INITIALIZING);
> + if (bo->uuid_state != UUID_INITIALIZED)
> + return -ENODEV;
> +
> + uuid_copy(uuid, &bo->uuid);
> +
> + return 0;
> +}
> +
> +struct dma_buf *virtgpu_gem_prime_export(struct drm_gem_object *obj,
> + int flags)
> +{
> + struct virtio_gpu_object *bo = gem_to_virtio_gpu_obj(obj);
> + struct virtio_gpu_device *vgdev = obj->dev->dev_private;
> + struct virtio_gpu_object_array *objs;
> + int ret = 0;
> +
> + if (vgdev->has_resource_assign_uuid) {
> + objs = virtio_gpu_array_alloc(1);
> + if (!objs)
> + return ERR_PTR(-ENOMEM);
> + virtio_gpu_array_add_obj(objs, &bo->base.base);
> +
> + ret = virtio_gpu_cmd_resource_assign_uuid(vgdev, objs);
> + if (ret)
> + return ERR_PTR(ret);
> + } else {
> + bo->uuid_state = UUID_INITIALIZATION_FAILED;
> + }
> +
> + return drm_gem_prime_export(obj, flags);
> +}
>
> struct drm_gem_object *virtgpu_gem_prime_import_sg_table(
> struct drm_device *dev, struct dma_buf_attachment *attach,
> diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
> index cfe9c54f87a3..b968eaa46bb0 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_vq.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
> @@ -1111,3 +1111,58 @@ void virtio_gpu_cursor_ping(struct virtio_gpu_device *vgdev,
> memcpy(cur_p, &output->cursor, sizeof(output->cursor));
> virtio_gpu_queue_cursor(vgdev, vbuf);
> }
> +
> +static void virtio_gpu_cmd_resource_uuid_cb(struct virtio_gpu_device *vgdev,
> + struct virtio_gpu_vbuffer *vbuf)
> +{
> + struct virtio_gpu_object *obj =
> + gem_to_virtio_gpu_obj(vbuf->objs->objs[0]);
> + struct virtio_gpu_resp_resource_uuid *resp =
> + (struct virtio_gpu_resp_resource_uuid *)vbuf->resp_buf;
> + uint32_t resp_type = le32_to_cpu(resp->hdr.type);
> +
> + spin_lock(&vgdev->resource_export_lock);
> + WARN_ON(obj->uuid_state != UUID_INITIALIZING);
> +
> + if (resp_type == VIRTIO_GPU_RESP_OK_RESOURCE_UUID &&
> + obj->uuid_state == UUID_INITIALIZING) {
> + memcpy(&obj->uuid.b, resp->uuid, sizeof(obj->uuid.b));
> + obj->uuid_state = UUID_INITIALIZED;
> + } else {
> + obj->uuid_state = UUID_INITIALIZATION_FAILED;
> + }
> + spin_unlock(&vgdev->resource_export_lock);
> +
> + wake_up_all(&vgdev->resp_wq);
> +}
> +
> +int
> +virtio_gpu_cmd_resource_assign_uuid(struct virtio_gpu_device *vgdev,
> + struct virtio_gpu_object_array *objs)
> +{
> + struct virtio_gpu_object *bo = gem_to_virtio_gpu_obj(objs->objs[0]);
> + struct virtio_gpu_resource_assign_uuid *cmd_p;
> + struct virtio_gpu_vbuffer *vbuf;
> + struct virtio_gpu_resp_resource_uuid *resp_buf;
> +
> + resp_buf = kzalloc(sizeof(*resp_buf), GFP_KERNEL);
> + if (!resp_buf) {
> + spin_lock(&vgdev->resource_export_lock);
> + bo->uuid_state = UUID_INITIALIZATION_FAILED;
> + spin_unlock(&vgdev->resource_export_lock);
> + virtio_gpu_array_put_free(objs);
> + return -ENOMEM;
> + }
> +
> + cmd_p = virtio_gpu_alloc_cmd_resp(vgdev,
> + virtio_gpu_cmd_resource_uuid_cb, &vbuf, sizeof(*cmd_p),
> + sizeof(struct virtio_gpu_resp_resource_uuid), resp_buf);
> + memset(cmd_p, 0, sizeof(*cmd_p));
> +
> + cmd_p->hdr.type = cpu_to_le32(VIRTIO_GPU_CMD_RESOURCE_ASSIGN_UUID);
> + cmd_p->resource_id = cpu_to_le32(bo->hw_res_handle);
> +
> + vbuf->objs = objs;
> + virtio_gpu_queue_ctrl_buffer(vgdev, vbuf);
> + return 0;
> +}
> --
> 2.25.1.481.gfbce0eb801-goog
> > + if (virtio_has_feature(vgdev->vdev, VIRTIO_GPU_F_RESOURCE_UUID)) {
> > + vgdev->has_resource_assign_uuid = true;
> > + }
>
>
> Just a question: this relies on DMA bufs so I assume it is
> not really assumed to work when DMA API is bypassed, right?
> Rather than worry what does it mean, how about just
> disabling this feature without PLATFORM_DMA for now?
By PLATFORM_DMA, do you mean CONFIG_DMA_SHARED_BUFFER? Virtio-gpu
depends on DRM, which selects that feature. So I think DMA bufs should
always be available when virtio-gpu is present.
-David
On Fri, May 15, 2020 at 04:26:15PM +0900, David Stevens wrote:
> > > + if (virtio_has_feature(vgdev->vdev, VIRTIO_GPU_F_RESOURCE_UUID)) {
> > > + vgdev->has_resource_assign_uuid = true;
> > > + }
> >
> >
> > Just a question: this relies on DMA bufs so I assume it is
> > not really assumed to work when DMA API is bypassed, right?
> > Rather than worry what does it mean, how about just
> > disabling this feature without PLATFORM_DMA for now?
>
> By PLATFORM_DMA, do you mean CONFIG_DMA_SHARED_BUFFER?
Sorry, no. I mean VIRTIO_F_IOMMU_PLATFORM which in the
future will be renamed to VIRTIO_F_PLATFORM_ACCESS.
> Virtio-gpu
> depends on DRM, which selects that feature. So I think DMA bufs should
> always be available when virtio-gpu is present.
>
> -David
On Mon, Jun 8, 2020 at 6:43 PM Michael S. Tsirkin <[email protected]> wrote:
>
> On Fri, May 15, 2020 at 04:26:15PM +0900, David Stevens wrote:
> > > > + if (virtio_has_feature(vgdev->vdev, VIRTIO_GPU_F_RESOURCE_UUID)) {
> > > > + vgdev->has_resource_assign_uuid = true;
> > > > + }
> > >
> > >
> > > Just a question: this relies on DMA bufs so I assume it is
> > > not really assumed to work when DMA API is bypassed, right?
> > > Rather than worry what does it mean, how about just
> > > disabling this feature without PLATFORM_DMA for now?
> >
> > By PLATFORM_DMA, do you mean CONFIG_DMA_SHARED_BUFFER?
>
> Sorry, no. I mean VIRTIO_F_IOMMU_PLATFORM which in the
> future will be renamed to VIRTIO_F_PLATFORM_ACCESS.
Shouldn't things work independent of whether or not that feature is
set? If a virtio driver properly uses the dma_buf APIs (which virtgpu
seems to), then that should take care of any mapping/synchronization
related to VIRTIO_F_IOMMU_PLATFORM. If anything, the case where
VIRTIO_F_IOMMU_PLATFORM isn't set is easier, since then we know that
the "the device has same access [sic] to memory addresses supplied to
it as the driver has", according to the specification.
-David
On Mon, Jun 08, 2020 at 07:36:55PM +0900, David Stevens wrote:
> On Mon, Jun 8, 2020 at 6:43 PM Michael S. Tsirkin <[email protected]> wrote:
> >
> > On Fri, May 15, 2020 at 04:26:15PM +0900, David Stevens wrote:
> > > > > + if (virtio_has_feature(vgdev->vdev, VIRTIO_GPU_F_RESOURCE_UUID)) {
> > > > > + vgdev->has_resource_assign_uuid = true;
> > > > > + }
> > > >
> > > >
> > > > Just a question: this relies on DMA bufs so I assume it is
> > > > not really assumed to work when DMA API is bypassed, right?
> > > > Rather than worry what does it mean, how about just
> > > > disabling this feature without PLATFORM_DMA for now?
> > >
> > > By PLATFORM_DMA, do you mean CONFIG_DMA_SHARED_BUFFER?
> >
> > Sorry, no. I mean VIRTIO_F_IOMMU_PLATFORM which in the
> > future will be renamed to VIRTIO_F_PLATFORM_ACCESS.
>
> Shouldn't things work independent of whether or not that feature is
> set? If a virtio driver properly uses the dma_buf APIs (which virtgpu
> seems to), then that should take care of any mapping/synchronization
> related to VIRTIO_F_IOMMU_PLATFORM. If anything, the case where
> VIRTIO_F_IOMMU_PLATFORM isn't set is easier, since then we know that
> the "the device has same access [sic] to memory addresses supplied to
> it as the driver has", according to the specification.
>
> -David
I don't know much about drm so I can't tell, I was hoping Gerd can
explain.
--
MST