[v5,3/3] drm/virtio: Support sync objects
Commit Message
Add sync object DRM UAPI support to VirtIO-GPU driver. Sync objects
support is needed by native context VirtIO-GPU Mesa drivers, it also will
be used by Venus and Virgl contexts.
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
---
drivers/gpu/drm/virtio/virtgpu_drv.c | 3 +-
drivers/gpu/drm/virtio/virtgpu_submit.c | 214 ++++++++++++++++++++++++
include/uapi/drm/virtgpu_drm.h | 16 +-
3 files changed, 231 insertions(+), 2 deletions(-)
Comments
Hi Dmitry,
On Sun, 9 Apr 2023 at 13:40, Dmitry Osipenko
<dmitry.osipenko@collabora.com> wrote:
> +static void virtio_gpu_free_syncobjs(struct drm_syncobj **syncobjs,
> + uint32_t nr_syncobjs)
> +{
> + uint32_t i = nr_syncobjs;
> +
> + while (i--) {
> + if (syncobjs[i])
> + drm_syncobj_put(syncobjs[i]);
> + }
> +
> + kvfree(syncobjs);
> +}
> +
> +static void virtio_gpu_reset_syncobjs(struct drm_syncobj **syncobjs,
> + uint32_t nr_syncobjs)
> +{
> + uint32_t i;
> +
> + for (i = 0; i < nr_syncobjs; i++) {
> + if (syncobjs[i])
> + drm_syncobj_replace_fence(syncobjs[i], NULL);
> + }
> +}
> +
Can I bribe you (with cookies) about dropping the NULL checks above?
They're dead code and rather misleading IMHO.
> +static void
> +virtio_gpu_free_post_deps(struct virtio_gpu_submit_post_dep *post_deps,
> + uint32_t nr_syncobjs)
> +{
> + uint32_t i = nr_syncobjs;
> +
> + while (i--) {
> + kfree(post_deps[i].chain);
> + drm_syncobj_put(post_deps[i].syncobj);
> + }
> +
> + kvfree(post_deps);
> +}
> +
> +static int virtio_gpu_parse_post_deps(struct virtio_gpu_submit *submit)
> +{
> + struct drm_virtgpu_execbuffer *exbuf = submit->exbuf;
> + struct drm_virtgpu_execbuffer_syncobj syncobj_desc;
> + struct virtio_gpu_submit_post_dep *post_deps;
> + u32 num_out_syncobjs = exbuf->num_out_syncobjs;
> + size_t syncobj_stride = exbuf->syncobj_stride;
> + int ret = 0, i;
> +
> + if (!num_out_syncobjs)
> + return 0;
> +
> + post_deps = kvcalloc(num_out_syncobjs, sizeof(*post_deps), GFP_KERNEL);
> + if (!post_deps)
> + return -ENOMEM;
> +
> + for (i = 0; i < num_out_syncobjs; i++) {
> + uint64_t address = exbuf->out_syncobjs + i * syncobj_stride;
> +
For my own education: what's the specifics/requirements behind the
stride? is there a use-case for the stride to vary across in/out
syncobj?
Off the top of my head: userspace could have an array of larger
structs, each embedding an syncobj. Thus passing the stride, the
kernel will fetch/update them in-place w/o caring about the other
data.
Or perhaps there is another trick that userspace utilises the stride for?
> + if (copy_from_user(&syncobj_desc,
> + u64_to_user_ptr(address),
> + min(syncobj_stride, sizeof(syncobj_desc)))) {
> + ret = -EFAULT;
> + break;
> + }
> +
We seem to be parsing garbage(?) stack data in the syncobj_stride <
sizeof(syncobj_desc) case.
Zeroing/reseting the syncobj_desc on each iteration is one approach -
be that fully or in part. Alternatively we could error out on
syncobj_stride < sizeof(syncobj_desc).
> + post_deps[i].point = syncobj_desc.point;
> +
> + if (syncobj_desc.flags) {
> + ret = -EINVAL;
> + break;
> + }
> +
> + if (syncobj_desc.point) {
> + post_deps[i].chain = dma_fence_chain_alloc();
> + if (!post_deps[i].chain) {
> + ret = -ENOMEM;
> + break;
> + }
> + }
> +
> + post_deps[i].syncobj = drm_syncobj_find(submit->file,
> + syncobj_desc.handle);
> + if (!post_deps[i].syncobj) {
> + ret = -EINVAL;
I think we want a kfree(chain) here. Otherwise we'll leak it, right?
> + break;
> + }
> + }
> +
> + if (ret) {
> + virtio_gpu_free_post_deps(post_deps, i);
> + return ret;
> + }
> +
> + submit->num_out_syncobjs = num_out_syncobjs;
> + submit->post_deps = post_deps;
> +
> + return 0;
> +}
> +
With the two issues in virtio_gpu_parse_post_deps() addressed, the series is:
Reviewed-by; Emil Velikov <emil.velikov@collabora.com>
HTH
Emil
Hello,
On 4/11/23 14:07, Emil Velikov wrote:
> Hi Dmitry,
>
> On Sun, 9 Apr 2023 at 13:40, Dmitry Osipenko
> <dmitry.osipenko@collabora.com> wrote:
>
>> +static void virtio_gpu_free_syncobjs(struct drm_syncobj **syncobjs,
>> + uint32_t nr_syncobjs)
>> +{
>> + uint32_t i = nr_syncobjs;
>> +
>> + while (i--) {
>> + if (syncobjs[i])
>> + drm_syncobj_put(syncobjs[i]);
>> + }
>> +
>> + kvfree(syncobjs);
>> +}
>> +
>
>> +static void virtio_gpu_reset_syncobjs(struct drm_syncobj **syncobjs,
>> + uint32_t nr_syncobjs)
>> +{
>> + uint32_t i;
>> +
>> + for (i = 0; i < nr_syncobjs; i++) {
>> + if (syncobjs[i])
>> + drm_syncobj_replace_fence(syncobjs[i], NULL);
>> + }
>> +}
>> +
>
> Can I bribe you (with cookies) about dropping the NULL checks above?
> They're dead code and rather misleading IMHO.
When userspace doesn't set the VIRTGPU_EXECBUF_SYNCOBJ_RESET flag in
virtio_gpu_parse_deps(), the syncobjs[i] is NULL. Hence not a dead code
at all :)
>> +static void
>> +virtio_gpu_free_post_deps(struct virtio_gpu_submit_post_dep *post_deps,
>> + uint32_t nr_syncobjs)
>> +{
>> + uint32_t i = nr_syncobjs;
>> +
>> + while (i--) {
>> + kfree(post_deps[i].chain);
>> + drm_syncobj_put(post_deps[i].syncobj);
>> + }
>> +
>> + kvfree(post_deps);
>> +}
>> +
>> +static int virtio_gpu_parse_post_deps(struct virtio_gpu_submit *submit)
>> +{
>> + struct drm_virtgpu_execbuffer *exbuf = submit->exbuf;
>> + struct drm_virtgpu_execbuffer_syncobj syncobj_desc;
>> + struct virtio_gpu_submit_post_dep *post_deps;
>> + u32 num_out_syncobjs = exbuf->num_out_syncobjs;
>> + size_t syncobj_stride = exbuf->syncobj_stride;
>> + int ret = 0, i;
>> +
>> + if (!num_out_syncobjs)
>> + return 0;
>> +
>> + post_deps = kvcalloc(num_out_syncobjs, sizeof(*post_deps), GFP_KERNEL);
>> + if (!post_deps)
>> + return -ENOMEM;
>> +
>> + for (i = 0; i < num_out_syncobjs; i++) {
>> + uint64_t address = exbuf->out_syncobjs + i * syncobj_stride;
>> +
>
> For my own education: what's the specifics/requirements behind the
> stride? is there a use-case for the stride to vary across in/out
> syncobj?
Stride is the same for in/out syncobjs as the same struct
drm_virtgpu_execbuffer_syncobj is used by both.
The out-syncobj don't use the "flags" field of
drm_virtgpu_execbuffer_syncobj. We could use separate strides and desc
for in/out syncobjs, but in practice it's unlikely that we will be
extending the desc anytime soon and usually there are not many
out-syncobj to care about the wasted field.
On the other hand, if we will ever need to extend desc for in-syncobjs,
there will be more wasted fields. Maybe it indeed won't hurt to split
in/out syncobjs, for consistency. I'll think about it for v6, thanks.
> Off the top of my head: userspace could have an array of larger
> structs, each embedding an syncobj. Thus passing the stride, the
> kernel will fetch/update them in-place w/o caring about the other
> data.
> Or perhaps there is another trick that userspace utilises the stride for?
Stride is only about potential future expansion of the struct
drm_virtgpu_execbuffer_syncobj with new fields. There shouldn't be any
special tricks for userspace to use.
>> + if (copy_from_user(&syncobj_desc,
>> + u64_to_user_ptr(address),
>> + min(syncobj_stride, sizeof(syncobj_desc)))) {
>> + ret = -EFAULT;
>> + break;
>> + }
>> +
>
> We seem to be parsing garbage(?) stack data in the syncobj_stride <
> sizeof(syncobj_desc) case.
>
> Zeroing/reseting the syncobj_desc on each iteration is one approach -
> be that fully or in part. Alternatively we could error out on
> syncobj_stride < sizeof(syncobj_desc).
Good catch! It indeed needs to be zeroed. Nothing terrible will happen
today for kernel if it will use garbage data, but a malfunctioning
userspace may happen to appear working properly.
>> + post_deps[i].point = syncobj_desc.point;
>> +
>> + if (syncobj_desc.flags) {
>> + ret = -EINVAL;
>> + break;
>> + }
>> +
>> + if (syncobj_desc.point) {
>> + post_deps[i].chain = dma_fence_chain_alloc();
>> + if (!post_deps[i].chain) {
>> + ret = -ENOMEM;
>> + break;
>> + }
>> + }
>> +
>> + post_deps[i].syncobj = drm_syncobj_find(submit->file,
>> + syncobj_desc.handle);
>> + if (!post_deps[i].syncobj) {
>> + ret = -EINVAL;
>
> I think we want a kfree(chain) here. Otherwise we'll leak it, right?
I'm sure there was a kfree here in one of previous version of the patch.
Another good catch, thanks :)
>> + break;
>> + }
>> + }
>> +
>> + if (ret) {
>> + virtio_gpu_free_post_deps(post_deps, i);
>> + return ret;
>> + }
>> +
>> + submit->num_out_syncobjs = num_out_syncobjs;
>> + submit->post_deps = post_deps;
>> +
>> + return 0;
>> +}
>> +
>
>
> With the two issues in virtio_gpu_parse_post_deps() addressed, the series is:
> Reviewed-by; Emil Velikov <emil.velikov@collabora.com>
Thanks you for the review!
@@ -176,7 +176,8 @@ static const struct drm_driver driver = {
* If KMS is disabled DRIVER_MODESET and DRIVER_ATOMIC are masked
* out via drm_device::driver_features:
*/
- .driver_features = DRIVER_MODESET | DRIVER_GEM | DRIVER_RENDER | DRIVER_ATOMIC,
+ .driver_features = DRIVER_MODESET | DRIVER_GEM | DRIVER_RENDER | DRIVER_ATOMIC |
+ DRIVER_SYNCOBJ | DRIVER_SYNCOBJ_TIMELINE,
.open = virtio_gpu_driver_open,
.postclose = virtio_gpu_driver_postclose,
@@ -14,11 +14,24 @@
#include <linux/uaccess.h>
#include <drm/drm_file.h>
+#include <drm/drm_syncobj.h>
#include <drm/virtgpu_drm.h>
#include "virtgpu_drv.h"
+struct virtio_gpu_submit_post_dep {
+ struct drm_syncobj *syncobj;
+ struct dma_fence_chain *chain;
+ uint64_t point;
+};
+
struct virtio_gpu_submit {
+ struct virtio_gpu_submit_post_dep *post_deps;
+ unsigned int num_out_syncobjs;
+
+ struct drm_syncobj **in_syncobjs;
+ unsigned int num_in_syncobjs;
+
struct virtio_gpu_object_array *buflist;
struct drm_virtgpu_execbuffer *exbuf;
struct virtio_gpu_fence *out_fence;
@@ -59,6 +72,194 @@ static int virtio_gpu_dma_fence_wait(struct virtio_gpu_submit *submit,
return 0;
}
+static void virtio_gpu_free_syncobjs(struct drm_syncobj **syncobjs,
+ uint32_t nr_syncobjs)
+{
+ uint32_t i = nr_syncobjs;
+
+ while (i--) {
+ if (syncobjs[i])
+ drm_syncobj_put(syncobjs[i]);
+ }
+
+ kvfree(syncobjs);
+}
+
+static int
+virtio_gpu_parse_deps(struct virtio_gpu_submit *submit)
+{
+ struct drm_virtgpu_execbuffer *exbuf = submit->exbuf;
+ struct drm_virtgpu_execbuffer_syncobj syncobj_desc;
+ size_t syncobj_stride = exbuf->syncobj_stride;
+ u32 num_in_syncobjs = exbuf->num_in_syncobjs;
+ struct drm_syncobj **syncobjs;
+ int ret = 0, i;
+
+ if (!num_in_syncobjs)
+ return 0;
+
+ /*
+ * kvalloc at first tries to allocate memory using kmalloc and
+ * falls back to vmalloc only on failure. It also uses GFP_NOWARN
+ * internally for allocations larger than a page size, preventing
+ * storm of KMSG warnings.
+ */
+ syncobjs = kvcalloc(num_in_syncobjs, sizeof(*syncobjs), GFP_KERNEL);
+ if (!syncobjs)
+ return -ENOMEM;
+
+ for (i = 0; i < num_in_syncobjs; i++) {
+ uint64_t address = exbuf->in_syncobjs + i * syncobj_stride;
+ struct dma_fence *fence;
+
+ if (copy_from_user(&syncobj_desc,
+ u64_to_user_ptr(address),
+ min(syncobj_stride, sizeof(syncobj_desc)))) {
+ ret = -EFAULT;
+ break;
+ }
+
+ if (syncobj_desc.flags & ~VIRTGPU_EXECBUF_SYNCOBJ_FLAGS) {
+ ret = -EINVAL;
+ break;
+ }
+
+ ret = drm_syncobj_find_fence(submit->file, syncobj_desc.handle,
+ syncobj_desc.point, 0, &fence);
+ if (ret)
+ break;
+
+ ret = virtio_gpu_dma_fence_wait(submit, fence);
+
+ dma_fence_put(fence);
+ if (ret)
+ break;
+
+ if (syncobj_desc.flags & VIRTGPU_EXECBUF_SYNCOBJ_RESET) {
+ syncobjs[i] = drm_syncobj_find(submit->file,
+ syncobj_desc.handle);
+ if (!syncobjs[i]) {
+ ret = -EINVAL;
+ break;
+ }
+ }
+ }
+
+ if (ret) {
+ virtio_gpu_free_syncobjs(syncobjs, i);
+ return ret;
+ }
+
+ submit->num_in_syncobjs = num_in_syncobjs;
+ submit->in_syncobjs = syncobjs;
+
+ return ret;
+}
+
+static void virtio_gpu_reset_syncobjs(struct drm_syncobj **syncobjs,
+ uint32_t nr_syncobjs)
+{
+ uint32_t i;
+
+ for (i = 0; i < nr_syncobjs; i++) {
+ if (syncobjs[i])
+ drm_syncobj_replace_fence(syncobjs[i], NULL);
+ }
+}
+
+static void
+virtio_gpu_free_post_deps(struct virtio_gpu_submit_post_dep *post_deps,
+ uint32_t nr_syncobjs)
+{
+ uint32_t i = nr_syncobjs;
+
+ while (i--) {
+ kfree(post_deps[i].chain);
+ drm_syncobj_put(post_deps[i].syncobj);
+ }
+
+ kvfree(post_deps);
+}
+
+static int virtio_gpu_parse_post_deps(struct virtio_gpu_submit *submit)
+{
+ struct drm_virtgpu_execbuffer *exbuf = submit->exbuf;
+ struct drm_virtgpu_execbuffer_syncobj syncobj_desc;
+ struct virtio_gpu_submit_post_dep *post_deps;
+ u32 num_out_syncobjs = exbuf->num_out_syncobjs;
+ size_t syncobj_stride = exbuf->syncobj_stride;
+ int ret = 0, i;
+
+ if (!num_out_syncobjs)
+ return 0;
+
+ post_deps = kvcalloc(num_out_syncobjs, sizeof(*post_deps), GFP_KERNEL);
+ if (!post_deps)
+ return -ENOMEM;
+
+ for (i = 0; i < num_out_syncobjs; i++) {
+ uint64_t address = exbuf->out_syncobjs + i * syncobj_stride;
+
+ if (copy_from_user(&syncobj_desc,
+ u64_to_user_ptr(address),
+ min(syncobj_stride, sizeof(syncobj_desc)))) {
+ ret = -EFAULT;
+ break;
+ }
+
+ post_deps[i].point = syncobj_desc.point;
+
+ if (syncobj_desc.flags) {
+ ret = -EINVAL;
+ break;
+ }
+
+ if (syncobj_desc.point) {
+ post_deps[i].chain = dma_fence_chain_alloc();
+ if (!post_deps[i].chain) {
+ ret = -ENOMEM;
+ break;
+ }
+ }
+
+ post_deps[i].syncobj = drm_syncobj_find(submit->file,
+ syncobj_desc.handle);
+ if (!post_deps[i].syncobj) {
+ ret = -EINVAL;
+ break;
+ }
+ }
+
+ if (ret) {
+ virtio_gpu_free_post_deps(post_deps, i);
+ return ret;
+ }
+
+ submit->num_out_syncobjs = num_out_syncobjs;
+ submit->post_deps = post_deps;
+
+ return 0;
+}
+
+static void
+virtio_gpu_process_post_deps(struct virtio_gpu_submit *submit)
+{
+ struct virtio_gpu_submit_post_dep *post_deps = submit->post_deps;
+ struct dma_fence *fence = &submit->out_fence->f;
+ uint32_t i;
+
+ for (i = 0; i < submit->num_out_syncobjs; i++) {
+ if (post_deps[i].chain) {
+ drm_syncobj_add_point(post_deps[i].syncobj,
+ post_deps[i].chain,
+ fence, post_deps[i].point);
+ post_deps[i].chain = NULL;
+ } else {
+ drm_syncobj_replace_fence(post_deps[i].syncobj, fence);
+ }
+ }
+}
+
static int virtio_gpu_fence_event_create(struct drm_device *dev,
struct drm_file *file,
struct virtio_gpu_fence *fence,
@@ -122,6 +323,10 @@ static int virtio_gpu_init_submit_buflist(struct virtio_gpu_submit *submit)
static void virtio_gpu_cleanup_submit(struct virtio_gpu_submit *submit)
{
+ virtio_gpu_reset_syncobjs(submit->in_syncobjs, submit->num_in_syncobjs);
+ virtio_gpu_free_syncobjs(submit->in_syncobjs, submit->num_in_syncobjs);
+ virtio_gpu_free_post_deps(submit->post_deps, submit->num_out_syncobjs);
+
if (!IS_ERR(submit->buf))
kvfree(submit->buf);
@@ -288,6 +493,14 @@ int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data,
* optimize the path by proceeding directly to the submission
* to virtio after the waits.
*/
+ ret = virtio_gpu_parse_post_deps(&submit);
+ if (ret)
+ goto cleanup;
+
+ ret = virtio_gpu_parse_deps(&submit);
+ if (ret)
+ goto cleanup;
+
ret = virtio_gpu_wait_in_fence(&submit);
if (ret)
goto cleanup;
@@ -303,6 +516,7 @@ int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data,
* the job submission path.
*/
virtio_gpu_install_out_fence_fd(&submit);
+ virtio_gpu_process_post_deps(&submit);
virtio_gpu_complete_submit(&submit);
cleanup:
virtio_gpu_cleanup_submit(&submit);
@@ -64,6 +64,16 @@ struct drm_virtgpu_map {
__u32 pad;
};
+#define VIRTGPU_EXECBUF_SYNCOBJ_RESET 0x01
+#define VIRTGPU_EXECBUF_SYNCOBJ_FLAGS ( \
+ VIRTGPU_EXECBUF_SYNCOBJ_RESET | \
+ 0)
+struct drm_virtgpu_execbuffer_syncobj {
+ __u32 handle;
+ __u32 flags;
+ __u64 point;
+};
+
/* fence_fd is modified on success if VIRTGPU_EXECBUF_FENCE_FD_OUT flag is set. */
struct drm_virtgpu_execbuffer {
__u32 flags;
@@ -73,7 +83,11 @@ struct drm_virtgpu_execbuffer {
__u32 num_bo_handles;
__s32 fence_fd; /* in/out fence fd (see VIRTGPU_EXECBUF_FENCE_FD_IN/OUT) */
__u32 ring_idx; /* command ring index (see VIRTGPU_EXECBUF_RING_IDX) */
- __u32 pad;
+ __u32 syncobj_stride;
+ __u32 num_in_syncobjs;
+ __u32 num_out_syncobjs;
+ __u64 in_syncobjs;
+ __u64 out_syncobjs;
};
#define VIRTGPU_PARAM_3D_FEATURES 1 /* do we have 3D features in the hw */