drm/amdgpu: reserve/unreserve vmid by vm ioctl v4

add reserve/unreserve vmid funtions. Used to reserve
vmids for certain shader debugging functionality that
required a fixed vmid for the life of the debug.

v3:
only reserve vmid from gfxhub
v4:
fix racy condition

Signed-off-by: Chunming Zhou <David1.Zhou@amd.com>
Reviewed-by: Junwei Zhang <Jerry.Zhang@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 51 insertions, 13 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 6eaeed08237c..86ef0cdfd04d 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -540,6 +540,45 @@ error:
         return r;
 }
 
+static void amdgpu_vm_free_reserved_vmid(struct amdgpu_device *adev,
+                                          struct amdgpu_vm *vm,
+                                          unsigned vmhub)
+{
+        struct amdgpu_vm_id_manager *id_mgr = &adev->vm_manager.id_mgr[vmhub];
+
+        mutex_lock(&id_mgr->lock);
+        if (vm->reserved_vmid[vmhub]) {
+                list_add(&vm->reserved_vmid[vmhub]->list,
+                        &id_mgr->ids_lru);
+                vm->reserved_vmid[vmhub] = NULL;
+        }
+        mutex_unlock(&id_mgr->lock);
+}
+
+static int amdgpu_vm_alloc_reserved_vmid(struct amdgpu_device *adev,
+                                         struct amdgpu_vm *vm,
+                                         unsigned vmhub)
+{
+        struct amdgpu_vm_id_manager *id_mgr;
+        struct amdgpu_vm_id *idle;
+        int r = 0;
+
+        id_mgr = &adev->vm_manager.id_mgr[vmhub];
+        mutex_lock(&id_mgr->lock);
+        if (vm->reserved_vmid[vmhub])
+                goto unlock;
+        /* Select the first entry VMID */
+        idle = list_first_entry(&id_mgr->ids_lru, struct amdgpu_vm_id, list);
+        list_del_init(&idle->list);
+        vm->reserved_vmid[vmhub] = idle;
+        mutex_unlock(&id_mgr->lock);
+
+        return 0;
+unlock:
+        mutex_unlock(&id_mgr->lock);
+        return r;
+}
+
 static bool amdgpu_vm_ring_has_compute_vm_bug(struct amdgpu_ring *ring)
 {
         struct amdgpu_device *adev = ring->adev;
@@ -2261,18 +2300,8 @@ void amdgpu_vm_fini(struct amdgpu_device *adev, struct amdgpu_vm *vm)
 
         amdgpu_vm_free_levels(&vm->root);
         dma_fence_put(vm->last_dir_update);
-        for (i = 0; i < AMDGPU_MAX_VMHUBS; i++) {
-                struct amdgpu_vm_id_manager *id_mgr =
-                        &adev->vm_manager.id_mgr[i];
-
-                mutex_lock(&id_mgr->lock);
-                if (vm->reserved_vmid[i]) {
-                        list_add(&vm->reserved_vmid[i]->list,
-                                 &id_mgr->ids_lru);
-                        vm->reserved_vmid[i] = NULL;
-                }
-                mutex_unlock(&id_mgr->lock);
-        }
+        for (i = 0; i < AMDGPU_MAX_VMHUBS; i++)
+                amdgpu_vm_free_reserved_vmid(adev, vm, i);
 }
 
 /**
@@ -2341,11 +2370,20 @@ void amdgpu_vm_manager_fini(struct amdgpu_device *adev)
 int amdgpu_vm_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
 {
         union drm_amdgpu_vm *args = data;
+        struct amdgpu_device *adev = dev->dev_private;
+        struct amdgpu_fpriv *fpriv = filp->driver_priv;
+        int r;
 
         switch (args->in.op) {
         case AMDGPU_VM_OP_RESERVE_VMID:
+                /* current, we only have requirement to reserve vmid from gfxhub */
+                r = amdgpu_vm_alloc_reserved_vmid(adev, &fpriv->vm,
+                                                  AMDGPU_GFXHUB);
+                if (r)
+                        return r;
+                break;
         case AMDGPU_VM_OP_UNRESERVE_VMID:
-                return -EINVAL;
+                amdgpu_vm_free_reserved_vmid(adev, &fpriv->vm, AMDGPU_GFXHUB);
                 break;
         default:
                 return -EINVAL;