gpu: nvgpu: Direct GMMU PTE kind control

Allow userspace to control directly the PTE kind for the mappings by
supplying NVGPU_AS_MAP_BUFFER_FLAGS_DIRECT_KIND_CTRL for MAP_BUFFER_EX.

In particular, in this mode, the userspace will tell the kernel
whether the kind is compressible, and if so, what is the
incompressible fallback kind. By supplying only the compressible kind,
the userspace can require that the map kind will not be demoted to the
incompressible fallback kind in case of comptag allocation failure.

Add also a GPU characteristics flag
NVGPU_GPU_FLAGS_SUPPORT_MAP_DIRECT_KIND_CTRL to signal whether direct
kind control is supported.

Fix indentation of nvgpu_as_map_buffer_ex_args header comment.

Bug 1705731

Change-Id: I317ab474ae53b78eb8fdd31bd6bca0541fcba9a4
Signed-off-by: Sami Kiminki <skiminki@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1543462
Reviewed-by: svc-mobile-coverity <svc-mobile-coverity@nvidia.com>
Reviewed-by: Konsta Holtta <kholtta@nvidia.com>
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Alex Waterman <alexw@nvidia.com>
Reviewed-by: svccoveritychecker <svccoveritychecker@nvidia.com>
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

drivers/gpu/nvgpu/common/linux/cde.c

@@ -975,7 +975,7 @@ __releases(&l->cde_app->mutex)
 	u64 big_page_mask = 0;
 	u32 flags;
 	int err, i;
-	const s32 compbits_kind = 0;
+	const s16 compbits_kind = 0;
 
 	gk20a_dbg(gpu_dbg_cde, "compbits_byte_offset=%llu scatterbuffer_byte_offset=%llu",
 		  compbits_byte_offset, scatterbuffer_byte_offset);
@@ -1038,8 +1038,11 @@ __releases(&l->cde_app->mutex)
 	/* map the destination buffer */
 	get_dma_buf(compbits_scatter_buf); /* a ref for nvgpu_vm_map */
 	map_vaddr = nvgpu_vm_map(cde_ctx->vm, compbits_scatter_buf, 0,
-				 NVGPU_MAP_BUFFER_FLAGS_CACHEABLE_TRUE,
-				 compbits_kind, true,
+				 NVGPU_AS_MAP_BUFFER_FLAGS_CACHEABLE |
+				 NVGPU_AS_MAP_BUFFER_FLAGS_DIRECT_KIND_CTRL,
+				 NV_KIND_INVALID,
+				 compbits_kind, /* incompressible kind */
+				 true,
 				 gk20a_mem_flag_none,
 				 map_offset, map_size,
 				 NULL);

drivers/gpu/nvgpu/common/linux/ioctl_as.c

@@ -79,11 +79,22 @@ static int gk20a_as_ioctl_map_buffer_ex(
 		struct gk20a_as_share *as_share,
 		struct nvgpu_as_map_buffer_ex_args *args)
 {
+	s16 compressible_kind;
+	s16 incompressible_kind;
+
 	gk20a_dbg_fn("");
 
+	if (args->flags & NVGPU_AS_MAP_BUFFER_FLAGS_DIRECT_KIND_CTRL) {
+		compressible_kind = args->compr_kind;
+		incompressible_kind = args->incompr_kind;
+	} else {
+		compressible_kind = args->kind;
+		incompressible_kind = NV_KIND_INVALID;
+	}
+
 	return nvgpu_vm_map_buffer(as_share->vm, args->dmabuf_fd,
 				   &args->offset, args->flags,
-				   args->kind,
+				   compressible_kind, incompressible_kind,
 				   args->buffer_offset,
 				   args->mapping_size,
 				   NULL);
@@ -97,6 +108,7 @@ static int gk20a_as_ioctl_map_buffer(
 	return nvgpu_vm_map_buffer(as_share->vm, args->dmabuf_fd,
 				   &args->o_a.offset,
 				   args->flags, NV_KIND_DEFAULT,
+				   NV_KIND_DEFAULT,
 				   0, 0, NULL);
 	/* args->o_a.offset will be set if !err */
 }
@@ -158,6 +170,9 @@ static int gk20a_as_ioctl_map_buffer_batch(
 	}
 
 	for (i = 0; i < args->num_maps; ++i) {
+		s16 compressible_kind;
+		s16 incompressible_kind;
+
 		struct nvgpu_as_map_buffer_ex_args map_args;
 		memset(&map_args, 0, sizeof(map_args));
 
@@ -167,10 +182,19 @@ static int gk20a_as_ioctl_map_buffer_batch(
 			break;
 		}
 
+		if (map_args.flags &
+		    NVGPU_AS_MAP_BUFFER_FLAGS_DIRECT_KIND_CTRL) {
+			compressible_kind = map_args.compr_kind;
+			incompressible_kind = map_args.incompr_kind;
+		} else {
+			compressible_kind = map_args.kind;
+			incompressible_kind = NV_KIND_INVALID;
+		}
+
 		err = nvgpu_vm_map_buffer(
 			as_share->vm, map_args.dmabuf_fd,
 			&map_args.offset, map_args.flags,
-			map_args.kind,
+			compressible_kind, incompressible_kind,
 			map_args.buffer_offset,
 			map_args.mapping_size,
 			&batch);

drivers/gpu/nvgpu/common/linux/vm.c

@@ -177,11 +177,46 @@ static u64 __nvgpu_vm_find_mapping(struct vm_gk20a *vm,
 	return mapped_buffer->addr;
 }
 
+static int setup_bfr_kind_fields(struct buffer_attrs *bfr, s16 compr_kind,
+				 s16 incompr_kind, u32 flags)
+{
+	if (flags & NVGPU_AS_MAP_BUFFER_FLAGS_DIRECT_KIND_CTRL) {
+		/* were we supplied with a kind in either parameter? */
+		if ((compr_kind < 0 || compr_kind >= NV_KIND_ATTR_SIZE) &&
+		    (incompr_kind < 0 || incompr_kind >= NV_KIND_ATTR_SIZE))
+			return -EINVAL;
+
+		if (compr_kind != NV_KIND_INVALID) {
+			bfr->use_kind_v = true;
+			bfr->kind_v = (u8)compr_kind;
+		}
+
+		if (incompr_kind != NV_KIND_INVALID) {
+			bfr->use_uc_kind_v = true;
+			bfr->uc_kind_v = (u8)incompr_kind;
+		}
+	} else {
+		if (compr_kind < 0 || compr_kind >= NV_KIND_ATTR_SIZE)
+			return -EINVAL;
+
+		bfr->use_kind_v = true;
+		bfr->kind_v = (u8)compr_kind;
+
+		/*
+		 * Note: setup_buffer_kind_and_compression() will
+		 * figure out uc_kind_v or return an error
+		 */
+	}
+
+	return 0;
+}
+
 u64 nvgpu_vm_map(struct vm_gk20a *vm,
 		 struct dma_buf *dmabuf,
 		 u64 offset_align,
 		 u32 flags,
-		 int kind,
+		 s16 compr_kind,
+		 s16 incompr_kind,
 		 bool user_mapped,
 		 int rw_flag,
 		 u64 buffer_offset,
@@ -203,6 +238,22 @@ u64 nvgpu_vm_map(struct vm_gk20a *vm,
 	u32 ctag_offset;
 	enum nvgpu_aperture aperture;
 
+	/*
+	 * The kind used as part of the key for map caching. HW may
+	 * actually be programmed with the fallback kind in case the
+	 * key kind is compressible but we're out of comptags.
+	 */
+	s16 map_key_kind;
+
+	if (flags & NVGPU_AS_MAP_BUFFER_FLAGS_DIRECT_KIND_CTRL) {
+		if (compr_kind != NV_KIND_INVALID)
+			map_key_kind = compr_kind;
+		else
+			map_key_kind = incompr_kind;
+	} else {
+		map_key_kind = compr_kind;
+	}
+
 	if (user_mapped && vm->userspace_managed &&
 	    !(flags & NVGPU_AS_MAP_BUFFER_FLAGS_FIXED_OFFSET)) {
 		nvgpu_err(g, "non-fixed-offset mapping not available on "
@@ -216,7 +267,7 @@ u64 nvgpu_vm_map(struct vm_gk20a *vm,
 	if (!vm->userspace_managed) {
 		map_offset = __nvgpu_vm_find_mapping(
 			vm, dmabuf, offset_align,
-			flags, kind,
+			flags, map_key_kind,
 			user_mapped, rw_flag);
 		if (map_offset) {
 			nvgpu_mutex_release(&vm->update_gmmu_lock);
@@ -239,12 +290,10 @@ u64 nvgpu_vm_map(struct vm_gk20a *vm,
 		goto clean_up;
 	}
 
-	if (kind >= NV_KIND_ATTR_SIZE) {
-		err = -EINVAL;
+	err = setup_bfr_kind_fields(&bfr, compr_kind, incompr_kind, flags);
+	if (err)
 		goto clean_up;
-	} else {
-		bfr.kind_v = (u8)kind;
-	}
+
 	bfr.size = dmabuf->size;
 	sgl = bfr.sgt->sgl;
 
@@ -306,10 +355,15 @@ u64 nvgpu_vm_map(struct vm_gk20a *vm,
 		err = gk20a_alloc_comptags(g, dev, dmabuf,
 					   ctag_allocator,
 					   bfr.ctag_lines);
-		if (err) {
-			/* ok to fall back here if we ran out */
+		if (unlikely(err)) {
 			/* TBD: we can partially alloc ctags as well... */
-			bfr.kind_v = bfr.uc_kind_v;
+			if (bfr.use_uc_kind_v) {
+				/* no comptags, but fallback kind available */
+				bfr.kind_v = bfr.uc_kind_v;
+			} else {
+				nvgpu_err(g, "comptag alloc failed and no fallback kind specified");
+				goto clean_up;
+			}
 		} else {
 			gk20a_get_comptags(dev,
 					   dmabuf, &comptags);
@@ -371,7 +425,7 @@ u64 nvgpu_vm_map(struct vm_gk20a *vm,
 	mapped_buffer->ctag_allocated_lines = bfr.ctag_allocated_lines;
 	mapped_buffer->vm          = vm;
 	mapped_buffer->flags       = flags;
-	mapped_buffer->kind        = kind;
+	mapped_buffer->kind        = map_key_kind;
 	mapped_buffer->va_allocated = va_allocated;
 	mapped_buffer->user_mapped = user_mapped ? 1 : 0;
 	mapped_buffer->own_mem_ref = user_mapped;

drivers/gpu/nvgpu/common/linux/vm_priv.h

@@ -34,7 +34,9 @@ struct buffer_attrs {
 	u32 ctag_allocated_lines;
 	int pgsz_idx;
 	u8 kind_v;
+	bool use_kind_v;
 	u8 uc_kind_v;
+	bool use_uc_kind_v;
 	bool ctag_user_mappable;
 };
 
@@ -42,19 +44,43 @@ u64 nvgpu_vm_map(struct vm_gk20a *vm,
 		 struct dma_buf *dmabuf,
 		 u64 offset_align,
 		 u32 flags,
-		 int kind,
+
+		 /*
+		  * compressible kind if
+		  * NVGPU_AS_MAP_BUFFER_FLAGS_DIRECT_KIND_CTRL is
+		  * specified, otherwise just the kind
+		  */
+		 s16 compr_kind,
+
+		 /*
+		  * incompressible kind if
+		  * NVGPU_AS_MAP_BUFFER_FLAGS_DIRECT_KIND_CTRL is
+		  * specified, otherwise ignored
+		  */
+		 s16 incompr_kind,
+
 		 bool user_mapped,
 		 int rw_flag,
 		 u64 buffer_offset,
 		 u64 mapping_size,
 		 struct vm_gk20a_mapping_batch *mapping_batch);
 
-/* Note: batch may be NULL if map op is not part of a batch */
+/*
+ * Notes:
+ * - Batch may be NULL if map op is not part of a batch.
+ * - If NVGPU_AS_MAP_BUFFER_FLAGS_DIRECT_KIND_CTRL is set,
+ *   compr_kind and incompr_kind work as explained in nvgpu.h.
+ * - If NVGPU_AS_MAP_BUFFER_FLAGS_DIRECT_KIND_CTRL is NOT set,
+ *   compr_kind holds the kind and kernel will figure out whether
+ *   it is a compressible or incompressible kind. If compressible, kernel will
+ *   also figure out the incompressible counterpart or return an error.
+ */
 int nvgpu_vm_map_buffer(struct vm_gk20a *vm,
 			int dmabuf_fd,
 			u64 *offset_align,
 			u32 flags, /* NVGPU_AS_MAP_BUFFER_FLAGS_ */
-			int kind,
+			s16 compr_kind,
+			s16 incompr_kind,
 			u64 buffer_offset,
 			u64 mapping_size,
 			struct vm_gk20a_mapping_batch *batch);