[PATCH v5 4/5] drm/i915/gvt: Dmabuf support for GVT-g

[Xiaoguang Chen]

dmabuf for GVT-g can be exported to users who can use the dmabuf to show
the desktop of vm which use intel vgpu.

Currently we provide query and create new dmabuf operations.

Users of dmabuf can cache some created dmabufs and related information
such as the framebuffer's address, size, tiling mode, width, height etc.
When refresh the screen first query the currnet vgpu's frambuffer and
compare with the cached ones(address, size, tiling, width, height etc)
if found one then reuse the found dmabuf to gain performance improvment.

If there is no dmabuf created yet or not found in the cached dmabufs then
need to create a new dmabuf. To create a dmabuf first a gem object will
be created and the backing storage of this gem object is the vgpu's
framebuffer(primary/cursor).
Set caching mode, change tiling mode and set domains of this gem object
is not supported.
Then associate this gem object to a dmabuf and export this dmabuf.
A file descriptor will be generated for this dmabuf and this file
descriptor can be sent to user space to do display.

Signed-off-by: Xiaoguang Chen <xiaoguang.chen@xxxxxxxxx>
---
 drivers/gpu/drm/i915/gvt/Makefile      |   2 +-
 drivers/gpu/drm/i915/gvt/dmabuf.c      | 276 +++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/gvt/dmabuf.h      |  53 +++++++
 drivers/gpu/drm/i915/gvt/gvt.h         |   1 +
 drivers/gpu/drm/i915/i915_gem.c        |   8 +
 drivers/gpu/drm/i915/i915_gem_object.h |   9 ++
 6 files changed, 348 insertions(+), 1 deletion(-)
 create mode 100644 drivers/gpu/drm/i915/gvt/dmabuf.c
 create mode 100644 drivers/gpu/drm/i915/gvt/dmabuf.h

diff --git a/drivers/gpu/drm/i915/gvt/Makefile b/drivers/gpu/drm/i915/gvt/Makefile
index 192ca26..e480f7d 100644
--- a/drivers/gpu/drm/i915/gvt/Makefile
+++ b/drivers/gpu/drm/i915/gvt/Makefile
@@ -2,7 +2,7 @@ GVT_DIR := gvt
 GVT_SOURCE := gvt.o aperture_gm.o handlers.o vgpu.o trace_points.o firmware.o \
 	interrupt.o gtt.o cfg_space.o opregion.o mmio.o display.o edid.o \
 	execlist.o scheduler.o sched_policy.o render.o cmd_parser.o \
-	fb_decoder.o
+	fb_decoder.o dmabuf.o
 
 ccflags-y				+= -I$(src) -I$(src)/$(GVT_DIR) -Wall
 i915-y					+= $(addprefix $(GVT_DIR)/, $(GVT_SOURCE))
diff --git a/drivers/gpu/drm/i915/gvt/dmabuf.c b/drivers/gpu/drm/i915/gvt/dmabuf.c
new file mode 100644
index 0000000..415453b
--- /dev/null
+++ b/drivers/gpu/drm/i915/gvt/dmabuf.c
@@ -0,0 +1,276 @@
+/*
+ * Copyright 2017 Intel Corporation. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * Authors:
+ *    Zhiyuan Lv <zhiyuan.lv@xxxxxxxxx>
+ *
+ * Contributors:
+ *    Xiaoguang Chen <xiaoguang.chen@xxxxxxxxx>
+ */
+
+#include <linux/dma-buf.h>
+#include <drm/drmP.h>
+
+#include "i915_drv.h"
+#include "gvt.h"
+
+#define GEN8_DECODE_PTE(pte) \
+	((dma_addr_t)(((((u64)pte) >> 12) & 0x7ffffffULL) << 12))
+
+static struct sg_table *intel_vgpu_gem_get_pages(
+		struct drm_i915_gem_object *obj)
+{
+	struct drm_i915_private *dev_priv = to_i915(obj->base.dev);
+	struct sg_table *st;
+	struct scatterlist *sg;
+	int i, ret;
+	gen8_pte_t __iomem *gtt_entries;
+	unsigned int fb_gma = 0, fb_size = 0;
+	struct intel_vgpu_plane_info *plane_info;
+
+	plane_info = (struct intel_vgpu_plane_info *)obj->gvt_plane_info;
+	if (WARN_ON(!plane_info))
+		return ERR_PTR(-EINVAL);
+
+	fb_gma = plane_info->start;
+	fb_size = plane_info->size;
+
+	st = kmalloc(sizeof(*st), GFP_KERNEL);
+	if (!st) {
+		ret = -ENOMEM;
+		return ERR_PTR(ret);
+	}
+
+	ret = sg_alloc_table(st, fb_size, GFP_KERNEL);
+	if (ret) {
+		kfree(st);
+		return ERR_PTR(ret);
+	}
+	gtt_entries = (gen8_pte_t __iomem *)dev_priv->ggtt.gsm +
+		(fb_gma >> PAGE_SHIFT);
+	for_each_sg(st->sgl, sg, fb_size, i) {
+		sg->offset = 0;
+		sg->length = PAGE_SIZE;
+		sg_dma_address(sg) =
+			GEN8_DECODE_PTE(readq(&gtt_entries[i]));
+		sg_dma_len(sg) = PAGE_SIZE;
+	}
+
+	return st;
+}
+
+static void intel_vgpu_gem_put_pages(struct drm_i915_gem_object *obj,
+		struct sg_table *pages)
+{
+	struct intel_vgpu_plane_info *plane_info;
+
+	plane_info = (struct intel_vgpu_plane_info *)obj->gvt_plane_info;
+	if (WARN_ON(!plane_info))
+		return;
+
+	sg_free_table(pages);
+	kfree(pages);
+}
+
+static const struct drm_i915_gem_object_ops intel_vgpu_gem_ops = {
+	.flags = I915_GEM_OBJECT_IS_GVT_DMABUF,
+	.get_pages = intel_vgpu_gem_get_pages,
+	.put_pages = intel_vgpu_gem_put_pages,
+};
+
+static struct drm_i915_gem_object *intel_vgpu_create_gem(struct drm_device *dev,
+		struct intel_vgpu_plane_info *info)
+{
+	struct drm_i915_private *pri = dev->dev_private;
+	struct drm_i915_gem_object *obj;
+
+	obj = i915_gem_object_alloc(pri);
+	if (obj == NULL)
+		return NULL;
+
+	drm_gem_private_object_init(dev, &obj->base,
+		info->size << PAGE_SHIFT);
+	i915_gem_object_init(obj, &intel_vgpu_gem_ops);
+
+	obj->base.read_domains = I915_GEM_DOMAIN_GTT;
+	obj->base.write_domain = 0;
+	obj->framebuffer_references++;
+	obj->gvt_plane_info = info;
+
+	if (IS_SKYLAKE(pri)) {
+		unsigned int tiling_mode = 0;
+
+		switch (info->drm_format_mod << 10) {
+		case PLANE_CTL_TILED_LINEAR:
+			tiling_mode = I915_TILING_NONE;
+			break;
+		case PLANE_CTL_TILED_X:
+			tiling_mode = I915_TILING_X;
+			break;
+		case PLANE_CTL_TILED_Y:
+			tiling_mode = I915_TILING_Y;
+			break;
+		default:
+			gvt_dbg_core("not supported tiling mode\n");
+		}
+		obj->tiling_and_stride = tiling_mode | info->stride;
+	} else {
+		obj->tiling_and_stride = info->drm_format_mod ?
+					I915_TILING_X : 0;
+	}
+
+	return obj;
+}
+
+static struct intel_vgpu_plane_info *intel_vgpu_get_plane_info(
+		struct drm_device *dev,
+		struct intel_vgpu *vgpu, uint32_t plane_id)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_vgpu_primary_plane_format *p;
+	struct intel_vgpu_cursor_plane_format *c;
+	struct intel_vgpu_plane_info *info;
+	struct intel_vgpu_pipe_format *pipe;
+
+	info = kmalloc(sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return NULL;
+
+	pipe = intel_vgpu_decode_plane(dev, vgpu);
+	if (pipe == NULL)
+		return NULL;
+
+	if (plane_id == INTEL_GVT_PLANE_PRIMARY) {
+		p = &pipe->primary;
+		if (p != NULL) {
+			info->start = p->base;
+			info->width = p->width;
+			info->height = p->height;
+			info->stride = p->stride;
+			info->drm_format = p->drm_format;
+			info->drm_format_mod = p->tiled;
+			info->size = (((p->stride * p->height * p->bpp) / 8) +
+					(PAGE_SIZE - 1)) >> PAGE_SHIFT;
+		} else {
+			kfree(info);
+			gvt_vgpu_err("invalid primary plane\n");
+			return NULL;
+		}
+	} else if (plane_id == INTEL_GVT_PLANE_CURSOR) {
+		c = &pipe->cursor;
+		if (c != NULL) {
+			info->start = c->base;
+			info->width = c->width;
+			info->height = c->height;
+			info->stride = c->width * (c->bpp / 8);
+			info->drm_format_mod = 0;
+			info->x_pos = c->x_pos;
+			info->y_pos = c->y_pos;
+			info->size = (((info->stride * c->height * c->bpp) / 8)
+					+ (PAGE_SIZE - 1)) >> PAGE_SHIFT;
+		} else {
+			kfree(info);
+			gvt_vgpu_err("invalid cursor plane\n");
+			return NULL;
+		}
+	} else {
+		kfree(info);
+		gvt_vgpu_err("invalid plane id:%d\n", plane_id);
+		return NULL;
+	}
+
+	if (info->size == 0) {
+		kfree(info);
+		gvt_vgpu_err("fb size is zero\n");
+		return NULL;
+	}
+
+	if (info->start & (PAGE_SIZE - 1)) {
+		kfree(info);
+		gvt_vgpu_err("Not aligned fb address:0x%x\n", info->start);
+		return NULL;
+	}
+	if (((info->start >> PAGE_SHIFT) + info->size) >
+		ggtt_total_entries(&dev_priv->ggtt)) {
+		kfree(info);
+		gvt_vgpu_err("Invalid GTT offset or size\n");
+		return NULL;
+	}
+
+	if (!intel_gvt_ggtt_validate_range(vgpu, info->start, info->size)) {
+		kfree(info);
+		gvt_vgpu_err("invalid gma addr\n");
+		return NULL;
+	}
+
+	return info;
+}
+
+int intel_vgpu_query_plane(struct intel_vgpu *vgpu, void *args)
+{
+	struct drm_device *dev = &vgpu->gvt->dev_priv->drm;
+	struct intel_vgpu_plane_info *info = args;
+
+	info = intel_vgpu_get_plane_info(dev, vgpu, info->plane_id);
+	if (info == NULL)
+		return -EINVAL;
+
+	return 0;
+}
+
+int intel_vgpu_create_dmabuf(struct intel_vgpu *vgpu, void *args)
+{
+	struct dma_buf *dmabuf;
+	struct drm_i915_gem_object *obj;
+	struct drm_device *dev = &vgpu->gvt->dev_priv->drm;
+	struct intel_vgpu_dmabuf *gvt_dmabuf = args;
+	struct intel_vgpu_plane_info *info;
+	int ret;
+
+	info = intel_vgpu_get_plane_info(dev, vgpu,
+					gvt_dmabuf->plane_info.plane_id);
+	if (info == NULL)
+		return -EINVAL;
+
+	obj = intel_vgpu_create_gem(dev, info);
+	if (obj == NULL) {
+		gvt_vgpu_err("create gvt gem obj failed:%d\n", vgpu->id);
+		return -EINVAL;
+	}
+
+	dmabuf = i915_gem_prime_export(dev, &obj->base, DRM_CLOEXEC | DRM_RDWR);
+
+	if (IS_ERR(dmabuf)) {
+		gvt_vgpu_err("export dma-buf failed\n");
+		return -EINVAL;
+	}
+
+	ret = dma_buf_fd(dmabuf, DRM_CLOEXEC | DRM_RDWR);
+	if (ret < 0) {
+		gvt_vgpu_err("create dma-buf fd failed ret:%d\n", ret);
+		return -EINVAL;
+	}
+	gvt_dmabuf->fd = ret;
+	gvt_dmabuf->plane_info = *info;
+
+	return 0;
+}
diff --git a/drivers/gpu/drm/i915/gvt/dmabuf.h b/drivers/gpu/drm/i915/gvt/dmabuf.h
new file mode 100644
index 0000000..43562af
--- /dev/null
+++ b/drivers/gpu/drm/i915/gvt/dmabuf.h
@@ -0,0 +1,53 @@
+
+/*
+ * Copyright(c) 2017 Intel Corporation. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+
+#ifndef _GVT_DMABUF_H_
+#define _GVT_DMABUF_H_
+
+struct intel_vgpu_plane_info {
+	uint32_t plane_id;
+	uint32_t drm_format;
+	uint32_t width;
+	uint32_t height;
+	uint32_t stride;
+	uint32_t start;
+	uint32_t x_pos;
+	uint32_t y_pos;
+	uint32_t size;
+	uint64_t drm_format_mod;
+};
+
+#define INTEL_VGPU_QUERY_PLANE		0
+#define INTEL_VGPU_GENERATE_DMABUF	1
+
+struct intel_vgpu_dmabuf {
+	uint32_t fd;
+	struct intel_vgpu_plane_info plane_info;
+};
+
+int intel_vgpu_query_plane(struct intel_vgpu *vgpu, void *args);
+int intel_vgpu_create_dmabuf(struct intel_vgpu *vgpu, void *args);
+
+#endif
diff --git a/drivers/gpu/drm/i915/gvt/gvt.h b/drivers/gpu/drm/i915/gvt/gvt.h
index c42266c..763a8c5 100644
--- a/drivers/gpu/drm/i915/gvt/gvt.h
+++ b/drivers/gpu/drm/i915/gvt/gvt.h
@@ -47,6 +47,7 @@
 #include "render.h"
 #include "cmd_parser.h"
 #include "fb_decoder.h"
+#include "dmabuf.h"
 
 #define GVT_MAX_VGPU 8
 
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 0c1cbe9..54f7a0f 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1609,6 +1609,10 @@ i915_gem_set_domain_ioctl(struct drm_device *dev, void *data,
 	if (!obj)
 		return -ENOENT;
 
+	/* The obj is a gvt dma-buf object and set domain is not supported */
+	if (i915_gem_object_is_gvt_dmabuf(obj))
+		return -EPERM;
+
 	/* Try to flush the object off the GPU without holding the lock.
 	 * We will repeat the flush holding the lock in the normal manner
 	 * to catch cases where we are gazumped.
@@ -3717,6 +3721,10 @@ int i915_gem_set_caching_ioctl(struct drm_device *dev, void *data,
 	if (!obj)
 		return -ENOENT;
 
+	/* the obj is a gvt dma-buf and set caching mode is not supported */
+	if (i915_gem_object_is_gvt_dmabuf(obj))
+		return -EPERM;
+
 	if (obj->cache_level == level)
 		goto out;
 
diff --git a/drivers/gpu/drm/i915/i915_gem_object.h b/drivers/gpu/drm/i915/i915_gem_object.h
index 174cf92..986af43 100644
--- a/drivers/gpu/drm/i915/i915_gem_object.h
+++ b/drivers/gpu/drm/i915/i915_gem_object.h
@@ -39,6 +39,7 @@ struct drm_i915_gem_object_ops {
 	unsigned int flags;
 #define I915_GEM_OBJECT_HAS_STRUCT_PAGE 0x1
 #define I915_GEM_OBJECT_IS_SHRINKABLE   0x2
+#define I915_GEM_OBJECT_IS_GVT_DMABUF	0x4
 
 	/* Interface between the GEM object and its backing storage.
 	 * get_pages() is called once prior to the use of the associated set
@@ -184,6 +185,8 @@ struct drm_i915_gem_object {
 		} userptr;
 
 		unsigned long scratch;
+
+		void *gvt_plane_info;
 	};
 
 	/** for phys allocated objects */
@@ -286,6 +289,12 @@ i915_gem_object_is_shrinkable(const struct drm_i915_gem_object *obj)
 }
 
 static inline bool
+i915_gem_object_is_gvt_dmabuf(const struct drm_i915_gem_object *obj)
+{
+	return obj->ops->flags & I915_GEM_OBJECT_IS_GVT_DMABUF;
+}
+
+static inline bool
 i915_gem_object_is_active(const struct drm_i915_gem_object *obj)
 {
 	return obj->active_count;
-- 
2.7.4