On 2025-07-24 22:43, Zhu Lingshan wrote:
> This commit implemetns a new ioctl AMDKFD_IOC_CREATE_PROCESS
> that creates a new secondary kfd_progress on the FD.
To add a new ioctl upstream, do you have a link to the corresponding
user mode changes?
Other than that, this patch looks good to me.
Regards,
Felix
>
> To keep backward compatibility, userspace programs need to invoke
> this ioctl explicitly on a FD to create a secondary
> kfd_process which replacing its primary kfd_process.
>
> This commit bumps ioctl minor version.
>
> Signed-off-by: Zhu Lingshan <lingshan.zhu at amd.com>
> ---
> drivers/gpu/drm/amd/amdkfd/kfd_chardev.c | 41 ++++++++++++++++++++++++
> drivers/gpu/drm/amd/amdkfd/kfd_priv.h | 1 +
> drivers/gpu/drm/amd/amdkfd/kfd_process.c | 3 +-
> include/uapi/linux/kfd_ioctl.h | 8 +++--
> 4 files changed, 49 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> index 5b22e1c47b2e..f9c43ff8a89f 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> @@ -3136,6 +3136,44 @@ static int kfd_ioctl_set_debug_trap(struct file *filep, struct kfd_process *p, v
> return r;
> }
>
> +/* userspace programs need to invoke this ioctl explicitly on a FD to
> + * create a secondary kfd_process which replacing its primary kfd_process
> + */
> +static int kfd_ioctl_create_process(struct file *filep, struct kfd_process *p, void *data)
> +{
> + struct kfd_process *process;
> + int ret;
> +
> + if (!filep->private_data || !p)
> + return -EINVAL;
> +
> + if (p != filep->private_data)
> + return -EINVAL;
> +
> + /* Each FD owns only one kfd_process */
> + if (!p->primary)
> + return -EINVAL;
> +
> + mutex_lock(&kfd_processes_mutex);
> + process = create_process(current, false);
> + mutex_unlock(&kfd_processes_mutex);
> +
> + if (IS_ERR(process))
> + return PTR_ERR(process);
> +
> + /* Each open() increases kref of the primary kfd_process,
> + * so we need to reduce it here before we create a new secondary process replacing it
> + */
> + kfd_unref_process(p);
> +
> + filep->private_data = process;
> + ret = kfd_create_process_sysfs(process);
> + if (ret)
> + pr_warn("Failed to create sysfs entry for the kfd_process");
> +
> + return 0;
> +}
> +
> #define AMDKFD_IOCTL_DEF(ioctl, _func, _flags) \
> [_IOC_NR(ioctl)] = {.cmd = ioctl, .func = _func, .flags = _flags, \
> .cmd_drv = 0, .name = #ioctl}
> @@ -3254,6 +3292,9 @@ static const struct amdkfd_ioctl_desc amdkfd_ioctls[] = {
>
> AMDKFD_IOCTL_DEF(AMDKFD_IOC_DBG_TRAP,
> kfd_ioctl_set_debug_trap, 0),
> +
> + AMDKFD_IOCTL_DEF(AMDKFD_IOC_CREATE_PROCESS,
> + kfd_ioctl_create_process, 0),
> };
>
> #define AMDKFD_CORE_IOCTL_COUNT ARRAY_SIZE(amdkfd_ioctls)
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> index a6e12c705734..a2b5081fbfc0 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> @@ -1051,6 +1051,7 @@ struct kfd_process *kfd_get_process(const struct task_struct *task);
> struct kfd_process *kfd_lookup_process_by_pasid(u32 pasid,
> struct kfd_process_device **pdd);
> struct kfd_process *kfd_lookup_process_by_mm(const struct mm_struct *mm);
> +struct kfd_process *create_process(const struct task_struct *thread, bool primary);
>
> int kfd_process_gpuidx_from_gpuid(struct kfd_process *p, uint32_t gpu_id);
> int kfd_process_gpuid_from_node(struct kfd_process *p, struct kfd_node *node,
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> index e1ba9015bb83..15a8de2275f4 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> @@ -71,7 +71,6 @@ static struct workqueue_struct *kfd_restore_wq;
> static struct kfd_process *find_process(const struct task_struct *thread,
> bool ref);
> static void kfd_process_ref_release(struct kref *ref);
> -static struct kfd_process *create_process(const struct task_struct *thread, bool primary);
>
> static void evict_process_worker(struct work_struct *work);
> static void restore_process_worker(struct work_struct *work);
> @@ -1598,7 +1597,7 @@ void kfd_process_set_trap_debug_flag(struct qcm_process_device *qpd,
> * On return the kfd_process is fully operational and will be freed when the
> * mm is released
> */
> -static struct kfd_process *create_process(const struct task_struct *thread, bool primary)
> +struct kfd_process *create_process(const struct task_struct *thread, bool primary)
> {
> struct kfd_process *process;
> struct mmu_notifier *mn;
> diff --git a/include/uapi/linux/kfd_ioctl.h b/include/uapi/linux/kfd_ioctl.h
> index 04c7d283dc7d..1d206ecc831e 100644
> --- a/include/uapi/linux/kfd_ioctl.h
> +++ b/include/uapi/linux/kfd_ioctl.h
> @@ -44,9 +44,10 @@
> * - 1.16 - Add contiguous VRAM allocation flag
> * - 1.17 - Add SDMA queue creation with target SDMA engine ID
> * - 1.18 - Rename pad in set_memory_policy_args to misc_process_flag
> + * - 1.19 - Add a new ioctl to craete secondary kfd processes
> */
> #define KFD_IOCTL_MAJOR_VERSION 1
> -#define KFD_IOCTL_MINOR_VERSION 18
> +#define KFD_IOCTL_MINOR_VERSION 19
>
> struct kfd_ioctl_get_version_args {
> __u32 major_version; /* from KFD */
> @@ -1671,7 +1672,10 @@ struct kfd_ioctl_dbg_trap_args {
> #define AMDKFD_IOC_DBG_TRAP \
> AMDKFD_IOWR(0x26, struct kfd_ioctl_dbg_trap_args)
>
> +#define AMDKFD_IOC_CREATE_PROCESS \
> + AMDKFD_IO(0x27)
> +
> #define AMDKFD_COMMAND_START 0x01
> -#define AMDKFD_COMMAND_END 0x27
> +#define AMDKFD_COMMAND_END 0x28
>
> #endif