drm/nvc0: enable protection of system-use-only structures in vm

Somehow missed this in the original merge of the nvc0 code.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nouveau_drv.h

@@ -160,6 +160,7 @@ enum nouveau_flags {
 #define NVOBJ_FLAG_ZERO_ALLOC		(1 << 1)
 #define NVOBJ_FLAG_ZERO_FREE		(1 << 2)
 #define NVOBJ_FLAG_VM			(1 << 3)
+#define NVOBJ_FLAG_VM_USER		(1 << 4)
 
 #define NVOBJ_CINST_GLOBAL	0xdeadbeef
 

drivers/gpu/drm/nouveau/nv50_instmem.c

@@ -332,8 +332,11 @@ nv50_instmem_get(struct nouveau_gpuobj *gpuobj, u32 size, u32 align)
 	gpuobj->vinst = node->vram->offset;
 
 	if (gpuobj->flags & NVOBJ_FLAG_VM) {
-		ret = nouveau_vm_get(dev_priv->chan_vm, size, 12,
-				     NV_MEM_ACCESS_RW | NV_MEM_ACCESS_SYS,
+		u32 flags = NV_MEM_ACCESS_RW;
+		if (!(gpuobj->flags & NVOBJ_FLAG_VM_USER))
+			flags |= NV_MEM_ACCESS_SYS;
+
+		ret = nouveau_vm_get(dev_priv->chan_vm, size, 12, flags,
 				     &node->chan_vma);
 		if (ret) {
 			vram->put(dev, &node->vram);

drivers/gpu/drm/nouveau/nvc0_graph.c

@@ -105,7 +105,8 @@ nvc0_graph_create_context_mmio_list(struct nouveau_channel *chan)
 	if (ret)
 		return ret;
 
-	ret = nouveau_gpuobj_new(dev, NULL, 384 * 1024, 4096, NVOBJ_FLAG_VM,
+	ret = nouveau_gpuobj_new(dev, NULL, 384 * 1024, 4096,
+				 NVOBJ_FLAG_VM | NVOBJ_FLAG_VM_USER,
 				 &grch->unk418810);
 	if (ret)
 		return ret;

drivers/gpu/drm/nouveau/nvc0_vm.c

@@ -48,8 +48,8 @@ nvc0_vm_addr(struct nouveau_vma *vma, u64 phys, u32 memtype, u32 target)
 	phys >>= 8;
 
 	phys |= 0x00000001; /* present */
-//	if (vma->access & NV_MEM_ACCESS_SYS)
-//		phys |= 0x00000002;
+	if (vma->access & NV_MEM_ACCESS_SYS)
+		phys |= 0x00000002;
 
 	phys |= ((u64)target  << 32);
 	phys |= ((u64)memtype << 36);