drm/amdgpu: Add helper to turn an existing VM into a compute VM

v2: Removed updating and checking of vm->vm_context
v3: Enable amdgpu_vm_clear_bo in amdgpu_vm_make_compute

Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>

2 files changed, 68 insertions, 0 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 24474294c92a..ea39ccf288ed 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -2462,6 +2462,73 @@ error_free_sched_entity:
 }
 
 /**
+ * amdgpu_vm_make_compute - Turn a GFX VM into a compute VM
+ *
+ * This only works on GFX VMs that don't have any BOs added and no
+ * page tables allocated yet.
+ *
+ * Changes the following VM parameters:
+ * - use_cpu_for_update
+ * - pte_supports_ats
+ * - pasid (old PASID is released, because compute manages its own PASIDs)
+ *
+ * Reinitializes the page directory to reflect the changed ATS
+ * setting. May leave behind an unused shadow BO for the page
+ * directory when switching from SDMA updates to CPU updates.
+ *
+ * Returns 0 for success, -errno for errors.
+ */
+int amdgpu_vm_make_compute(struct amdgpu_device *adev, struct amdgpu_vm *vm)
+{
+        bool pte_support_ats = (adev->asic_type == CHIP_RAVEN);
+        int r;
+
+        r = amdgpu_bo_reserve(vm->root.base.bo, true);
+        if (r)
+                return r;
+
+        /* Sanity checks */
+        if (!RB_EMPTY_ROOT(&vm->va.rb_root) || vm->root.entries) {
+                r = -EINVAL;
+                goto error;
+        }
+
+        /* Check if PD needs to be reinitialized and do it before
+         * changing any other state, in case it fails.
+         */
+        if (pte_support_ats != vm->pte_support_ats) {
+                r = amdgpu_vm_clear_bo(adev, vm, vm->root.base.bo,
+                               adev->vm_manager.root_level,
+                               pte_support_ats);
+                if (r)
+                        goto error;
+        }
+
+        /* Update VM state */
+        vm->use_cpu_for_update = !!(adev->vm_manager.vm_update_mode &
+                                    AMDGPU_VM_USE_CPU_FOR_COMPUTE);
+        vm->pte_support_ats = pte_support_ats;
+        DRM_DEBUG_DRIVER("VM update mode is %s\n",
+                         vm->use_cpu_for_update ? "CPU" : "SDMA");
+        WARN_ONCE((vm->use_cpu_for_update & !amdgpu_vm_is_large_bar(adev)),
+                  "CPU update of VM recommended only for large BAR system\n");
+
+        if (vm->pasid) {
+                unsigned long flags;
+
+                spin_lock_irqsave(&adev->vm_manager.pasid_lock, flags);
+                idr_remove(&adev->vm_manager.pasid_idr, vm->pasid);
+                spin_unlock_irqrestore(&adev->vm_manager.pasid_lock, flags);
+
+                vm->pasid = 0;
+        }
+
+error:
+        amdgpu_bo_unreserve(vm->root.base.bo);
+        return r;
+}
+
+/**
  * amdgpu_vm_free_levels - free PD/PT levels
  *
  * @adev: amdgpu device structure
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
index 4dfdefb7de1f..30f080364c97 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
@@ -260,6 +260,7 @@ void amdgpu_vm_manager_init(struct amdgpu_device *adev);
 void amdgpu_vm_manager_fini(struct amdgpu_device *adev);
 int amdgpu_vm_init(struct amdgpu_device *adev, struct amdgpu_vm *vm,
                    int vm_context, unsigned int pasid);
+int amdgpu_vm_make_compute(struct amdgpu_device *adev, struct amdgpu_vm *vm);
 void amdgpu_vm_fini(struct amdgpu_device *adev, struct amdgpu_vm *vm);
 bool amdgpu_vm_pasid_fault_credit(struct amdgpu_device *adev,
                                   unsigned int pasid);