Re: [PATCH v2 2/4] drm/amdgpu/gfx11: recover gfx user queues on priv-fault

On Tue, Jul 21, 2026 at 11:39 PM Jesse Zhang <[email protected]> wrote:
>
> If a priv/bad-op fault does not match a kernel queue slot, it belongs to
> a MES-scheduled user queue. Compute IVs carry the doorbell and use the
> existing path; gfx IVs do not, so record the faulted slot and let a
> worker read the doorbell back from the HQD (regCP_RB_DOORBELL_CONTROL),
> look up the user queue and reset it.
>
> Suggested-by: Mario Sopena-Novales <[email protected]>
> Signed-off-by: Jesse Zhang <[email protected]>
> ---
>  drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c | 60 +++++++++++++++++++++++---
>  1 file changed, 55 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c b/drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c
> index 0cbbdc3694f4..a802b0ac1544 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c
> @@ -1601,6 +1601,8 @@ static void gfx_v11_0_alloc_ip_dump(struct amdgpu_device *adev)
>         }
>  }
>
> +static void gfx_v11_0_userq_priv_fault_work(struct work_struct *work);
> +
>  static int gfx_v11_0_sw_init(struct amdgpu_ip_block *ip_block)
>  {
>         int i, j, k, r, ring_id;
> @@ -1931,6 +1933,8 @@ static int gfx_v11_0_sw_init(struct amdgpu_ip_block *ip_block)
>
>         mutex_init(&adev->gfx.mec.reset_mutex);
>
> +       INIT_WORK(&adev->gfx.userq_priv_fault_work, gfx_v11_0_userq_priv_fault_work);
> +
>         return 0;
>  }
>
> @@ -1968,6 +1972,8 @@ static int gfx_v11_0_sw_fini(struct amdgpu_ip_block *ip_block)
>         int i;
>         struct amdgpu_device *adev = ip_block->adev;
>
> +       cancel_work_sync(&adev->gfx.userq_priv_fault_work);
> +
>         for (i = 0; i < adev->gfx.num_gfx_rings; i++)
>                 amdgpu_ring_fini(&adev->gfx.gfx_ring[i]);
>         for (i = 0; i < adev->gfx.num_compute_rings; i++)
> @@ -6707,10 +6713,47 @@ static int gfx_v11_0_set_priv_inst_fault_state(struct amdgpu_device *adev,
>         return 0;
>  }
>
> +/*
> + * A gfx exception IV carries no doorbell. For each faulted slot, read the
> + * doorbell back from the HQD (left in place by the fatal fault), look up the
> + * user queue and kick its per-queue reset.
> + */
> +static void gfx_v11_0_userq_priv_fault_work(struct work_struct *work)
> +{
> +       struct amdgpu_device *adev =
> +               container_of(work, struct amdgpu_device, gfx.userq_priv_fault_work);
> +       unsigned long slots = xchg(&adev->gfx.userq_priv_fault_slots, 0);
> +       unsigned int id;
> +
> +       for_each_set_bit(id, &slots, BITS_PER_LONG) {
> +               u8 pipe = id & 0x3;
> +               u8 queue = (id >> 2) & 0x7;
> +               struct amdgpu_usermode_queue *q;
> +               u32 db_ctrl, doorbell;
> +
> +               amdgpu_gfx_off_ctrl(adev, false);
> +               mutex_lock(&adev->srbm_mutex);
> +               soc21_grbm_select(adev, 0, pipe, queue, 0);
> +               db_ctrl = RREG32_SOC15(GC, 0, regCP_RB_DOORBELL_CONTROL);
> +               soc21_grbm_select(adev, 0, 0, 0, 0);
> +               mutex_unlock(&adev->srbm_mutex);
> +               amdgpu_gfx_off_ctrl(adev, true);
> +
> +               doorbell = (db_ctrl & CP_RB_DOORBELL_CONTROL__DOORBELL_OFFSET_MASK) >>
> +                          CP_RB_DOORBELL_CONTROL__DOORBELL_OFFSET__SHIFT;
> +               q = xa_load(&adev->userq_doorbell_xa, doorbell);
> +               if (q)
> +                       amdgpu_userq_start_hang_detect_work(q);
> +       }
> +}
> +
>  static void gfx_v11_0_handle_priv_fault(struct amdgpu_device *adev,
>                                         struct amdgpu_iv_entry *entry)
>  {
>         u32 doorbell_offset = entry->src_data[0] & AMDGPU_CTXID0_DOORBELL_ID_MASK;
> +       u8 me_id = (entry->ring_id & 0x0c) >> 2;
> +       u8 pipe_id = (entry->ring_id & 0x03) >> 0;
> +       u8 queue_id = (entry->ring_id & 0x70) >> 4;
>
>         /*
>          * Try KQ first by ring_id (HW slot is authoritative). The
> @@ -6718,9 +6761,6 @@ static void gfx_v11_0_handle_priv_fault(struct amdgpu_device *adev,
>          * never share a HW slot.
>          */
>         if (!adev->gfx.disable_kq) {
> -               u8 me_id = (entry->ring_id & 0x0c) >> 2;
> -               u8 pipe_id = (entry->ring_id & 0x03) >> 0;
> -               u8 queue_id = (entry->ring_id & 0x70) >> 4;
>                 struct amdgpu_ring *ring;
>                 int i;
>
> @@ -6752,10 +6792,20 @@ static void gfx_v11_0_handle_priv_fault(struct amdgpu_device *adev,
>                 }
>         }
>
> -       /* No KQ matched: HW slot is a MES-scheduled user queue. */
> -       if (adev->enable_mes && doorbell_offset)
> +       /* No KQ matched: the faulting slot belongs to a user queue. */
> +       if (!adev->enable_mes)

I think this should be:

if (adev->gfx.disable_uq)
    return;

Same comment for patch 3.

> +               return;
> +
> +       if (doorbell_offset) {
>                 amdgpu_userq_process_reset_irq(adev, entry->pasid,
>                                                doorbell_offset);

If the doorbell offset is not provided, do we need to keep this code?
Same comment for patch 3.

Alex

> +       } else {
> +               /* GFX IVs lack the doorbell; record the slot and let the
> +                * worker read it back from the HQD.
> +                */
> +               set_bit(pipe_id | (queue_id << 2), &adev->gfx.userq_priv_fault_slots);
> +               schedule_work(&adev->gfx.userq_priv_fault_work);
> +       }
>  }
>
>  static int gfx_v11_0_priv_reg_irq(struct amdgpu_device *adev,
> --
> 2.49.0
>