[PATCH v3 2/4] drm/amdgpu/gfx11: recover gfx user queues on priv-fault

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.

v2:
 - gate on adev->gfx.disable_uq instead of !adev->enable_mes (Alex)
 - document why both the doorbell (compute) and HW-slot (gfx) reset
   paths are needed (Alex)

Suggested-by: Mario Sopena-Novales <[email protected]>
Signed-off-by: Jesse Zhang <[email protected]>
---
 drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c | 62 +++++++++++++++++++++++---
 1 file changed, 57 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..4c1ba5a9c75d 100644
--- a/drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c
@@ -362,6 +362,7 @@ static void gfx_v11_0_ring_invalidate_tlbs(struct amdgpu_ring *ring,
 					   bool all_hub, uint8_t dst_sel);
 static void gfx_v11_0_set_safe_mode(struct amdgpu_device *adev, int xcc_id);
 static void gfx_v11_0_unset_safe_mode(struct amdgpu_device *adev, int xcc_id);
+static void gfx_v11_0_userq_priv_fault_work(struct work_struct *work);
 static void gfx_v11_0_update_perf_clk(struct amdgpu_device *adev,
 				      bool enable);
 
@@ -1931,6 +1932,8 @@ 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 +1971,8 @@ 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 +6712,47 @@ 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 +6760,6 @@ 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 +6791,23 @@ 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->gfx.disable_uq)
+		return;
+
+	/*
+	 * A compute user-queue fault IV carries the doorbell offset, so reset the
+	 * queue directly from it. A gfx user-queue fault is raised by the ME and
+	 * carries only the HW slot (no doorbell); record the slot and let the
+	 * worker read the doorbell back from the HQD.
+	 */
+	if (doorbell_offset) {
 		amdgpu_userq_process_reset_irq(adev, entry->pasid,
 					       doorbell_offset);
+	} else {
+		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