[PATCH v2] drm/amdkfd: Move dma unmapping after TLB flush

[Philip Yang]

Otherwise GPU may access the stale mapping and generate IOMMU
IO_PAGE_FAULT.

Move this to inside p->mutex to prevent multiple threads mapping and
unmapping concurrently race condition.

After kfd_mem_dmaunmap_attachment is removed from unmap_bo_from_gpuvm,
kfd_mem_dmaunmap_attachment is called if failed to map to GPUs, and
before free the mem attachment in case failed to unmap from GPUs.

Signed-off-by: Philip Yang <Philip.Yang at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h    |  1 +
 .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c  | 22 +++++++++++++++---
 drivers/gpu/drm/amd/amdkfd/kfd_chardev.c      | 23 ++++++++++++-------
 3 files changed, 35 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
index 559f14cc0a99..dff79a623f4a 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
@@ -304,6 +304,7 @@ int amdgpu_amdkfd_gpuvm_map_memory_to_gpu(struct amdgpu_device *adev,
 					  struct kgd_mem *mem, void *drm_priv);
 int amdgpu_amdkfd_gpuvm_unmap_memory_from_gpu(
 		struct amdgpu_device *adev, struct kgd_mem *mem, void *drm_priv);
+void amdgpu_amdkfd_gpuvm_dmaunmap_mem(struct amdgpu_vm *vm, struct kgd_mem *mem);
 int amdgpu_amdkfd_gpuvm_sync_memory(
 		struct amdgpu_device *adev, struct kgd_mem *mem, bool intr);
 int amdgpu_amdkfd_gpuvm_map_gtt_bo_to_kernel(struct kgd_mem *mem,
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
index b5b940485059..ae767ad7afa2 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
@@ -1249,8 +1249,6 @@ static void unmap_bo_from_gpuvm(struct kgd_mem *mem,
 	amdgpu_vm_clear_freed(adev, vm, &bo_va->last_pt_update);
 
 	amdgpu_sync_fence(sync, bo_va->last_pt_update);
-
-	kfd_mem_dmaunmap_attachment(mem, entry);
 }
 
 static int update_gpuvm_pte(struct kgd_mem *mem,
@@ -1305,6 +1303,7 @@ static int map_bo_to_gpuvm(struct kgd_mem *mem,
 
 update_gpuvm_pte_failed:
 	unmap_bo_from_gpuvm(mem, entry, sync);
+	kfd_mem_dmaunmap_attachment(mem, entry);
 	return ret;
 }
 
@@ -1910,8 +1909,10 @@ int amdgpu_amdkfd_gpuvm_free_memory_of_gpu(
 		mem->va + bo_size * (1 + mem->aql_queue));
 
 	/* Remove from VM internal data structures */
-	list_for_each_entry_safe(entry, tmp, &mem->attachments, list)
+	list_for_each_entry_safe(entry, tmp, &mem->attachments, list) {
+		kfd_mem_dmaunmap_attachment(mem, entry);
 		kfd_mem_detach(entry);
+	}
 
 	ret = unreserve_bo_and_vms(&ctx, false, false);
 
@@ -2085,6 +2086,21 @@ int amdgpu_amdkfd_gpuvm_map_memory_to_gpu(
 	return ret;
 }
 
+void amdgpu_amdkfd_gpuvm_dmaunmap_mem(struct amdgpu_vm *vm, struct kgd_mem *mem)
+{
+	struct kfd_mem_attachment *entry;
+
+	mutex_lock(&mem->lock);
+
+	list_for_each_entry(entry, &mem->attachments, list) {
+		if (entry->bo_va->base.vm != vm)
+			continue;
+		kfd_mem_dmaunmap_attachment(mem, entry);
+	}
+
+	mutex_unlock(&mem->lock);
+}
+
 int amdgpu_amdkfd_gpuvm_unmap_memory_from_gpu(
 		struct amdgpu_device *adev, struct kgd_mem *mem, void *drm_priv)
 {
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
index 08687ce0aa8b..645628ff1faf 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
@@ -1432,17 +1432,24 @@ static int kfd_ioctl_unmap_memory_from_gpu(struct file *filep,
 			goto sync_memory_failed;
 		}
 	}
-	mutex_unlock(&p->mutex);
 
-	if (flush_tlb) {
-		/* Flush TLBs after waiting for the page table updates to complete */
-		for (i = 0; i < args->n_devices; i++) {
-			peer_pdd = kfd_process_device_data_by_id(p, devices_arr[i]);
-			if (WARN_ON_ONCE(!peer_pdd))
-				continue;
+	/* Flush TLBs after waiting for the page table updates to complete */
+	for (i = 0; i < args->n_devices; i++) {
+		struct amdgpu_vm *vm;
+
+		peer_pdd = kfd_process_device_data_by_id(p, devices_arr[i]);
+		if (WARN_ON_ONCE(!peer_pdd))
+			continue;
+		if (flush_tlb)
 			kfd_flush_tlb(peer_pdd, TLB_FLUSH_HEAVYWEIGHT);
-		}
+
+		/* Remove dma mapping after tlb flush to avoid IO_PAGE_FAULT */
+		vm = drm_priv_to_vm(peer_pdd->drm_priv);
+		amdgpu_amdkfd_gpuvm_dmaunmap_mem(vm, mem);
 	}
+
+	mutex_unlock(&p->mutex);
+
 	kfree(devices_arr);
 
 	return 0;
-- 
2.35.1