drm/nouveau/mmu: support initialisation of client-managed address-spaces

NVKM is currently responsible for managing the allocation of a client's
GPU address-space, but there's various use-cases (ie. HMM address-space
mirroring) where giving a client more direct control is desirable.

This commit allows for a VMM to be created where the area allocated for
NVKM is limited to a client-specified window, the remainder of address-
space is controlled directly by the client.

Leaving a window is necessary to support various internal requirements,
but also to support existing allocation interfaces as not all of the HW
is capable of working with a HMM allocation.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/include/nvif/if000c.h

@@ -3,7 +3,8 @@
 struct nvif_vmm_v0 {
 	__u8  version;
 	__u8  page_nr;
-	__u8  pad02[6];
+	__u8  managed;
+	__u8  pad03[5];
 	__u64 addr;
 	__u64 size;
 	__u8  data[];

drivers/gpu/drm/nouveau/include/nvif/vmm.h

@@ -30,8 +30,8 @@ struct nvif_vmm {
 	int page_nr;
 };
 
-int nvif_vmm_init(struct nvif_mmu *, s32 oclass, u64 addr, u64 size,
-		  void *argv, u32 argc, struct nvif_vmm *);
+int nvif_vmm_init(struct nvif_mmu *, s32 oclass, bool managed, u64 addr,
+		  u64 size, void *argv, u32 argc, struct nvif_vmm *);
 void nvif_vmm_fini(struct nvif_vmm *);
 int nvif_vmm_get(struct nvif_vmm *, enum nvif_vmm_get, bool sparse,
 		 u8 page, u8 align, u64 size, struct nvif_vma *);