[PATCH v12 1/3] drm/amdgpu: Add ioctl to get all gem handles for a process
Christian König
christian.koenig at amd.com
Tue Aug 12 09:36:38 UTC 2025
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.Francis at 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.
Regards,
Christian.
>
>> + 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
>
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