[PATCH] drm/amdgpu: Always emit GDS switch when GDS/GWS/OA is used

[Friedrich Vock <friedrich.vock@gmx.de>]

During gfxoff, the per-VMID GDS registers are reset and not restored
afterwards. The kernel needs to emit a GDS switch to manually update the
GWS registers in this case. Since gfxoff can happen between any two
submissions and the kernel has no way of knowing, emit the GDS switch
before every submission.

Fixes: 56b0989e29 ("drm/amdgpu: fix GDS/GWS/OA switch handling")
Cc: stable@vger.kernel.org
Link: https://gitlab.freedesktop.org/drm/amd/-/issues/2530
Signed-off-by: Friedrich Vock <friedrich.vock@gmx.de>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_ids.c | 22 +++++++---------------
 drivers/gpu/drm/amd/amdgpu/amdgpu_job.h |  1 -
 drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c  | 10 ++++++++--
 3 files changed, 15 insertions(+), 18 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ids.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ids.c
index ff1ea99292fb..de73797e9279 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ids.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ids.c
@@ -165,24 +165,17 @@ bool amdgpu_vmid_had_gpu_reset(struct amdgpu_device *adev,
 		atomic_read(&adev->gpu_reset_counter);
 }

-/* Check if we need to switch to another set of resources */
-static bool amdgpu_vmid_gds_switch_needed(struct amdgpu_vmid *id,
-					  struct amdgpu_job *job)
-{
-	return id->gds_base != job->gds_base ||
-		id->gds_size != job->gds_size ||
-		id->gws_base != job->gws_base ||
-		id->gws_size != job->gws_size ||
-		id->oa_base != job->oa_base ||
-		id->oa_size != job->oa_size;
-}
-
 /* Check if the id is compatible with the job */
 static bool amdgpu_vmid_compatible(struct amdgpu_vmid *id,
 				   struct amdgpu_job *job)
 {
 	return  id->pd_gpu_addr == job->vm_pd_addr &&
-		!amdgpu_vmid_gds_switch_needed(id, job);
+		id->gds_base == job->gds_base &&
+		id->gds_size == job->gds_size &&
+		id->gws_base == job->gws_base &&
+		id->gws_size == job->gws_size &&
+		id->oa_base == job->oa_base &&
+		id->oa_size == job->oa_size;
 }

 /**
@@ -434,7 +427,6 @@ int amdgpu_vmid_grab(struct amdgpu_vm *vm, struct amdgpu_ring *ring,
 		list_move_tail(&id->list, &id_mgr->ids_lru);
 	}

-	job->gds_switch_needed = amdgpu_vmid_gds_switch_needed(id, job);
 	if (job->vm_needs_flush) {
 		id->flushed_updates = amdgpu_vm_tlb_seq(vm);
 		dma_fence_put(id->last_flush);
@@ -503,7 +495,7 @@ void amdgpu_vmid_free_reserved(struct amdgpu_device *adev,
  * @vmhub: vmhub type
  * @vmid: vmid number to use
  *
- * Reset saved GDW, GWS and OA to force switch on next flush.
+ * Reset saved GDS, GWS and OA data.
  */
 void amdgpu_vmid_reset(struct amdgpu_device *adev, unsigned vmhub,
 		       unsigned vmid)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.h
index a963a25ddd62..2898508b1ce4 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.h
@@ -53,7 +53,6 @@ struct amdgpu_job {
 	uint32_t		preamble_status;
 	uint32_t                preemption_status;
 	bool                    vm_needs_flush;
-	bool			gds_switch_needed;
 	bool			spm_update_needed;
 	uint64_t		vm_pd_addr;
 	unsigned		vmid;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 291977b93b1d..61856040cae2 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -557,6 +557,12 @@ void amdgpu_vm_check_compute_bug(struct amdgpu_device *adev)
 	}
 }

+/* Check if the job needs a GDS switch */
+static bool amdgpu_vm_need_gds_switch(struct amdgpu_job *job)
+{
+	return job->gds_size || job->gws_size || job->oa_size;
+}
+
 /**
  * amdgpu_vm_need_pipeline_sync - Check if pipe sync is needed for job.
  *
@@ -579,7 +585,7 @@ bool amdgpu_vm_need_pipeline_sync(struct amdgpu_ring *ring,
 	if (job->vm_needs_flush || ring->has_compute_vm_bug)
 		return true;

-	if (ring->funcs->emit_gds_switch && job->gds_switch_needed)
+	if (ring->funcs->emit_gds_switch && amdgpu_vm_need_gds_switch(job))
 		return true;

 	if (amdgpu_vmid_had_gpu_reset(adev, &id_mgr->ids[job->vmid]))
@@ -609,7 +615,7 @@ int amdgpu_vm_flush(struct amdgpu_ring *ring, struct amdgpu_job *job,
 	struct amdgpu_vmid *id = &id_mgr->ids[job->vmid];
 	bool spm_update_needed = job->spm_update_needed;
 	bool gds_switch_needed = ring->funcs->emit_gds_switch &&
-		job->gds_switch_needed;
+		amdgpu_vm_need_gds_switch(job);
 	bool vm_flush_needed = job->vm_needs_flush;
 	struct dma_fence *fence = NULL;
 	bool pasid_mapping_needed = false;
--
2.41.0