On 12.08.25 11:56, Tvrtko Ursulin wrote:
>
> On 12/08/2025 10:36, Christian König wrote:
>> On 12.08.25 11:28, Tvrtko Ursulin wrote:
>>>
>>> On 11/08/2025 16:05, David Francis wrote:
>>>> Add new ioctl DRM_IOCTL_AMDGPU_GEM_LIST_HANDLES.
>>>>
>>>> This ioctl returns a list of bos with their handles, sizes,
>>>> and flags and domains.
>>>>
>>>> This ioctl is meant to be used during CRIU checkpoint and
>>>> provide information needed to reconstruct the bos
>>>> in CRIU restore.
>>>>
>>>> Signed-off-by: David Francis <david.fran...@amd.com>
>>>> ---
>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 1 +
>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c | 83 +++++++++++++++++++++++++
>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_gem.h | 2 +
>>>> include/uapi/drm/amdgpu_drm.h | 31 +++++++++
>>>> 4 files changed, 117 insertions(+)
>>>>
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
>>>> index 4ff3a2eaaf55..f19795dddf9d 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
>>>> @@ -3031,6 +3031,7 @@ const struct drm_ioctl_desc amdgpu_ioctls_kms[] = {
>>>> DRM_IOCTL_DEF_DRV(AMDGPU_USERQ, amdgpu_userq_ioctl,
>>>> DRM_AUTH|DRM_RENDER_ALLOW),
>>>> DRM_IOCTL_DEF_DRV(AMDGPU_USERQ_SIGNAL, amdgpu_userq_signal_ioctl,
>>>> DRM_AUTH|DRM_RENDER_ALLOW),
>>>> DRM_IOCTL_DEF_DRV(AMDGPU_USERQ_WAIT, amdgpu_userq_wait_ioctl,
>>>> DRM_AUTH|DRM_RENDER_ALLOW),
>>>> + DRM_IOCTL_DEF_DRV(AMDGPU_GEM_LIST_HANDLES,
>>>> amdgpu_gem_list_handles_ioctl, DRM_AUTH|DRM_RENDER_ALLOW),
>>>> };
>>>> static const struct drm_driver amdgpu_kms_driver = {
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>>>> index e3f65977eeee..3873d2c19b4b 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>>>> @@ -1032,6 +1032,89 @@ int amdgpu_gem_op_ioctl(struct drm_device *dev,
>>>> void *data,
>>>> return r;
>>>> }
>>>> +/**
>>>> + * drm_amdgpu_gem_list_handles_ioctl - get information about a process'
>>>> buffer objects
>>>> + *
>>>> + * @dev: drm device pointer
>>>> + * @data: drm_amdgpu_gem_list_handles
>>>> + * @filp: drm file pointer
>>>> + *
>>>> + * num_bos is set as an input to the size of the bo_buckets array.
>>>> + * num_bos is sent back as output as the number of bos in the process.
>>>> + * If that number is larger than the size of the array, the ioctl must
>>>> + * be retried.
>>>> + *
>>>> + * Returns:
>>>> + * 0 for success, -errno for errors.
>>>> + */
>>>> +int amdgpu_gem_list_handles_ioctl(struct drm_device *dev, void *data,
>>>> + struct drm_file *filp)
>>>> +{
>>>> + struct drm_amdgpu_gem_list_handles *args = data;
>>>> + struct drm_amdgpu_gem_list_handles_entry *bo_entries;
>>>> + struct drm_gem_object *gobj;
>>>> + int id, ret = 0;
>>>> + int bo_index = 0;
>>>> + int num_bos = 0;
>>>> +
>>>> + spin_lock(&filp->table_lock);
>>>> + idr_for_each_entry(&filp->object_idr, gobj, id)
>>>> + num_bos += 1;
>>>> + spin_unlock(&filp->table_lock);
>>>> +
>>>> + if (args->num_entries < num_bos) {
>>>> + args->num_entries = num_bos;
>>>> + return 0;
>>>> + }
>>>> +
>>>> + if (num_bos == 0) {
>>>> + args->num_entries = 0;
>>>> + return 0;
>>>> + }
>>>> +
>>>> + bo_entries = kvcalloc(num_bos, sizeof(*bo_entries), GFP_KERNEL);
>>>> + if (!bo_entries)
>>>> + return -ENOMEM;
>>>> +
>>>> + spin_lock(&filp->table_lock);
>>>> + idr_for_each_entry(&filp->object_idr, gobj, id) {
>>>> + struct amdgpu_bo *bo = gem_to_amdgpu_bo(gobj);
>>>> + struct drm_amdgpu_gem_list_handles_entry *bo_entry;
>>>> +
>>>> + if (bo_index >= num_bos) {
>>>> + ret = -EAGAIN;
>>>> + break;
>>>> + }
>>>> +
>>>> + bo_entry = &bo_entries[bo_index];
>>>> +
>>>> + bo_entry->size = amdgpu_bo_size(bo);
>>>> + bo_entry->alloc_flags = bo->flags &
>>>> (~AMDGPU_GEM_CREATE_VRAM_WIPE_ON_RELEASE);
>>>> + /* WIPE_ON_RELEASE is set automatically in the driver; it is not
>>>> permitted in
>>>> + * BO creation. In the interest of giving the user exactly the
>>>> flags they need
>>>> + * to recreate the BO, clear it.
>>>> + */
>>>
>>> Ha, curious. What is the reason flags userspace cannot use are specified in
>>> the uapi header?
>>
>> The comment isn't correct. AMDGPU_GEM_CREATE_VRAM_WIPE_ON_RELEASE is
>> perfectly allowed in the create IOCTL.
>
> I looked after reading the comment and it seemed true:
Oh, good point. Now I understand the issue. The GEM interface doesn't allowed
for the flag on create!
>
> amdgpu_gem_create_ioctl():
> ...
> uint64_t flags = args->in.domain_flags;
> ...
> /* reject invalid gem flags */
> if (flags & ~(AMDGPU_GEM_CREATE_CPU_ACCESS_REQUIRED |
> AMDGPU_GEM_CREATE_NO_CPU_ACCESS |
> AMDGPU_GEM_CREATE_CPU_GTT_USWC |
> AMDGPU_GEM_CREATE_VRAM_CLEARED |
> AMDGPU_GEM_CREATE_VM_ALWAYS_VALID |
> AMDGPU_GEM_CREATE_EXPLICIT_SYNC |
> AMDGPU_GEM_CREATE_ENCRYPTED |
> AMDGPU_GEM_CREATE_GFX12_DCC |
> AMDGPU_GEM_CREATE_DISCARDABLE))
> return -EINVAL;
>
> Actually, thinking about it more, maybe more flags should be cleared in
> amdgpu_gem_list_handles_ioctl()? Perhaps the above mask should be defined at
> a common place, or even internal only flags removed from the uapi header. Or
> uapi vs internal flags split or something.
Yeah, probably good idea. But it should most likely not be in an UAPI header.
The general background is that we have a bunch of flags only the kernel can set
and are read only for userspace.
Regards,
Christian.
>
> Regards,
>
> Tvrtko
>
>>>
>>>> + bo_entry->preferred_domains = bo->preferred_domains;
>>>> + bo_entry->gem_handle = id;
>>>> +
>>>> + if (bo->tbo.base.import_attach)
>>>> + bo_entry->flags |= AMDGPU_GEM_LIST_HANDLES_FLAG_IS_IMPORT;
>>>
>>> I had a question regarding this part in v11. Any comment on that?
>>>
>>> Anyway, thanks for implementing the other changes I suggested, this one
>>> LGTM now.
>>>
>>> Regards,
>>>
>>> Tvrtko
>>>
>>>> +
>>>> + bo_index += 1;
>>>> + }
>>>> + spin_unlock(&filp->table_lock);
>>>> +
>>>> + args->num_entries = bo_index;
>>>> +
>>>> + if (!ret)
>>>> + ret = copy_to_user(u64_to_user_ptr(args->entries), bo_entries,
>>>> num_bos * sizeof(*bo_entries));
>>>> +
>>>> + kvfree(bo_entries);
>>>> +
>>>> + return ret;
>>>> +}
>>>> +
>>>> +
>>>> static int amdgpu_gem_align_pitch(struct amdgpu_device *adev,
>>>> int width,
>>>> int cpp,
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.h
>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.h
>>>> index b51e8f95ee86..7cdb6237bb92 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.h
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.h
>>>> @@ -67,6 +67,8 @@ int amdgpu_gem_va_ioctl(struct drm_device *dev, void
>>>> *data,
>>>> struct drm_file *filp);
>>>> int amdgpu_gem_op_ioctl(struct drm_device *dev, void *data,
>>>> struct drm_file *filp);
>>>> +int amdgpu_gem_list_handles_ioctl(struct drm_device *dev, void *data,
>>>> + struct drm_file *filp);
>>>> int amdgpu_gem_metadata_ioctl(struct drm_device *dev, void *data,
>>>> struct drm_file *filp);
>>>> diff --git a/include/uapi/drm/amdgpu_drm.h b/include/uapi/drm/amdgpu_drm.h
>>>> index bdedbaccf776..59b423883e91 100644
>>>> --- a/include/uapi/drm/amdgpu_drm.h
>>>> +++ b/include/uapi/drm/amdgpu_drm.h
>>>> @@ -57,6 +57,7 @@ extern "C" {
>>>> #define DRM_AMDGPU_USERQ 0x16
>>>> #define DRM_AMDGPU_USERQ_SIGNAL 0x17
>>>> #define DRM_AMDGPU_USERQ_WAIT 0x18
>>>> +#define DRM_AMDGPU_GEM_LIST_HANDLES 0x19
>>>> #define DRM_IOCTL_AMDGPU_GEM_CREATE DRM_IOWR(DRM_COMMAND_BASE +
>>>> DRM_AMDGPU_GEM_CREATE, union drm_amdgpu_gem_create)
>>>> #define DRM_IOCTL_AMDGPU_GEM_MMAP DRM_IOWR(DRM_COMMAND_BASE +
>>>> DRM_AMDGPU_GEM_MMAP, union drm_amdgpu_gem_mmap)
>>>> @@ -77,6 +78,7 @@ extern "C" {
>>>> #define DRM_IOCTL_AMDGPU_USERQ DRM_IOWR(DRM_COMMAND_BASE +
>>>> DRM_AMDGPU_USERQ, union drm_amdgpu_userq)
>>>> #define DRM_IOCTL_AMDGPU_USERQ_SIGNAL DRM_IOWR(DRM_COMMAND_BASE +
>>>> DRM_AMDGPU_USERQ_SIGNAL, struct drm_amdgpu_userq_signal)
>>>> #define DRM_IOCTL_AMDGPU_USERQ_WAIT DRM_IOWR(DRM_COMMAND_BASE +
>>>> DRM_AMDGPU_USERQ_WAIT, struct drm_amdgpu_userq_wait)
>>>> +#define DRM_IOCTL_AMDGPU_GEM_LIST_HANDLES DRM_IOWR(DRM_COMMAND_BASE +
>>>> DRM_AMDGPU_GEM_LIST_HANDLES, struct drm_amdgpu_gem_list_handles)
>>>> /**
>>>> * DOC: memory domains
>>>> @@ -811,6 +813,35 @@ struct drm_amdgpu_gem_op {
>>>> __u64 value;
>>>> };
>>>> +#define AMDGPU_GEM_LIST_HANDLES_FLAG_IS_IMPORT (1 << 0)
>>>> +
>>>> +struct drm_amdgpu_gem_list_handles {
>>>> + /* User pointer to array of drm_amdgpu_gem_bo_info_entry */
>>>> + __u64 entries;
>>>> +
>>>> + /* IN: Size of entries buffer. OUT: Number of handles in process (if
>>>> larger than size of buffer, must retry) */
>>>> + __u32 num_entries;
>>>> +
>>>> + __u32 padding;
>>>> +};
>>>> +
>>>> +struct drm_amdgpu_gem_list_handles_entry {
>>>> + /* gem handle of buffer object */
>>>> + __u32 gem_handle;
>>>> +
>>>> + /* Currently just one flag: IS_IMPORT */
>>>> + __u32 flags;
>>>> +
>>>> + /* Size of bo */
>>>> + __u64 size;
>>>> +
>>>> + /* Preferred domains for GEM_CREATE */
>>>> + __u64 preferred_domains;
>>>> +
>>>> + /* GEM_CREATE flags for re-creation of buffer */
>>>> + __u64 alloc_flags;
>>>> +};
>>>> +
>>>> #define AMDGPU_VA_OP_MAP 1
>>>> #define AMDGPU_VA_OP_UNMAP 2
>>>> #define AMDGPU_VA_OP_CLEAR 3
>>>
>>
>
