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[PATCH v3 0/5] drm/i915/gvt: Dma-buf support for GVT-g

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  [PATCH v3 0/5] drm/i915/gvt: Dma-buf support for GVT-g Xiaoguang Chen <xiaoguang.chen@intel.com> - 2017-05-22 11:40 +0200
    [PATCH v3 1/5] drm/i915/gvt: Extend the GVT-g architecture to support vfio device region Xiaoguang Chen <xiaoguang.chen@intel.com> - 2017-05-22 11:40 +0200

#1646668 — [PATCH v3 0/5] drm/i915/gvt: Dma-buf support for GVT-g

v2->v3:
1) add a field gvt_plane_info in the drm_i915_gem_obj structure to save
the decoded plane information to avoid look up while need the plane info.
2) declare a new flag I915_GEM_OBJECT_IS_GVT_DMABUF in drm_i915_gem_object
to represent the gem obj for gvt's dma-buf. The tiling mode, caching mode
and domains can not be changed for this kind of gem object.
3) change dma-buf related information to be more generic. So other vendor
can use the same interface.

v1->v2:
1) create a management fd for dma-buf operations.
2) alloc gem object's backing storage in gem obj's get_pages() callback.

This patch set adds the dma-buf support for intel GVT-g.
dma-buf is a uniform mechanism to share DMA buffers across different
devices and sub-systems.
dma-buf for intel GVT-g is mainly used to share the vgpu's framebuffer
to other users or sub-systems so they can use the dma-buf to show the
desktop of a vm which uses intel vgpu.

The main idea is we create a gem object and set vgpu's framebuffer as
the backing storage of this gem object. And associate this gem obj
to a dma-buf object then export this dma-buf at the meantime
generate a file descriptor for this dma-buf. Finally deliver this file
descriptor to user space. And user can use this dma-buf fd to do render
or other operations.
User need to create a fd(for intel GVT-g dma-buf support it is a:dma-buf
management fd) then user can use this fd to query the plane information
or create a dma-buf. The life cycle of this fd is managed by GVT-g user
do not need to care about that.

We have an example program on how to use the dma-buf. You can download
the program to have a try. Good luck :)
git repo: https://github.com/01org/igvtg-qemu branch:kvmgt_dmabuf_example

Xiaoguang Chen (5):
  drm/i915/gvt: Extend the GVT-g architecture to support vfio device
    region
  drm/i915/gvt: OpRegion support for GVT-g
  drm/i915/gvt: Frame buffer decoder support for GVT-g
  drm/i915/gvt: Dmabuf support for GVT-g
  drm/i915/gvt: Adding interface so user space can get the dma-buf

 drivers/gpu/drm/i915/gvt/Makefile      |   3 +-
 drivers/gpu/drm/i915/gvt/display.c     |   2 +-
 drivers/gpu/drm/i915/gvt/display.h     |   2 +
 drivers/gpu/drm/i915/gvt/dmabuf.c      | 276 +++++++++++++++++++
 drivers/gpu/drm/i915/gvt/dmabuf.h      |  32 +++
 drivers/gpu/drm/i915/gvt/fb_decoder.c  | 487 +++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/gvt/fb_decoder.h  | 170 ++++++++++++
 drivers/gpu/drm/i915/gvt/gvt.c         |   2 +
 drivers/gpu/drm/i915/gvt/gvt.h         |   7 +
 drivers/gpu/drm/i915/gvt/kvmgt.c       | 205 +++++++++++++-
 drivers/gpu/drm/i915/gvt/opregion.c    |   8 +-
 drivers/gpu/drm/i915/i915_gem.c        |   8 +
 drivers/gpu/drm/i915/i915_gem_object.h |   3 +
 include/uapi/linux/vfio.h              |  36 +++
 14 files changed, 1235 insertions(+), 6 deletions(-)
 create mode 100644 drivers/gpu/drm/i915/gvt/dmabuf.c
 create mode 100644 drivers/gpu/drm/i915/gvt/dmabuf.h
 create mode 100644 drivers/gpu/drm/i915/gvt/fb_decoder.c
 create mode 100644 drivers/gpu/drm/i915/gvt/fb_decoder.h

-- 
2.7.4

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#1646673 — [PATCH v3 1/5] drm/i915/gvt: Extend the GVT-g architecture to support vfio device region

Signed-off-by: Xiaoguang Chen <xiaoguang.chen@intel.com>
---
 drivers/gpu/drm/i915/gvt/kvmgt.c | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index 1ae0b40..3c6a02b 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -53,11 +53,21 @@ static const struct intel_gvt_ops *intel_gvt_ops;
 #define VFIO_PCI_INDEX_TO_OFFSET(index) ((u64)(index) << VFIO_PCI_OFFSET_SHIFT)
 #define VFIO_PCI_OFFSET_MASK    (((u64)(1) << VFIO_PCI_OFFSET_SHIFT) - 1)
 
+struct vfio_region;
+struct intel_vgpu_regops {
+	size_t (*rw)(struct intel_vgpu *vgpu, char *buf,
+			size_t count, loff_t *ppos, bool iswrite);
+	void (*release)(struct intel_vgpu *vgpu,
+			struct vfio_region *region);
+};
+
 struct vfio_region {
 	u32				type;
 	u32				subtype;
 	size_t				size;
 	u32				flags;
+	const struct intel_vgpu_regops	*ops;
+	void				*data;
 };
 
 struct kvmgt_pgfn {
@@ -642,7 +652,7 @@ static ssize_t intel_vgpu_rw(struct mdev_device *mdev, char *buf,
 	int ret = -EINVAL;
 
 
-	if (index >= VFIO_PCI_NUM_REGIONS) {
+	if (index >= VFIO_PCI_NUM_REGIONS + vgpu->vdev.num_regions) {
 		gvt_vgpu_err("invalid index: %u\n", index);
 		return -EINVAL;
 	}
@@ -676,8 +686,11 @@ static ssize_t intel_vgpu_rw(struct mdev_device *mdev, char *buf,
 	case VFIO_PCI_BAR5_REGION_INDEX:
 	case VFIO_PCI_VGA_REGION_INDEX:
 	case VFIO_PCI_ROM_REGION_INDEX:
+		break;
 	default:
-		gvt_vgpu_err("unsupported region: %u\n", index);
+		index -= VFIO_PCI_NUM_REGIONS;
+		return vgpu->vdev.region[index].ops->rw(vgpu, buf, count,
+				ppos, is_write);
 	}
 
 	return ret == 0 ? count : ret;
@@ -940,7 +953,8 @@ static long intel_vgpu_ioctl(struct mdev_device *mdev, unsigned int cmd,
 
 		info.flags = VFIO_DEVICE_FLAGS_PCI;
 		info.flags |= VFIO_DEVICE_FLAGS_RESET;
-		info.num_regions = VFIO_PCI_NUM_REGIONS;
+		info.num_regions = VFIO_PCI_NUM_REGIONS +
+				vgpu->vdev.num_regions;
 		info.num_irqs = VFIO_PCI_NUM_IRQS;
 
 		return copy_to_user((void __user *)arg, &info, minsz) ?
@@ -1061,6 +1075,7 @@ static long intel_vgpu_ioctl(struct mdev_device *mdev, unsigned int cmd,
 		}
 
 		if (caps.size) {
+			info.flags |= VFIO_REGION_INFO_FLAG_CAPS;
 			if (info.argsz < sizeof(info) + caps.size) {
 				info.argsz = sizeof(info) + caps.size;
 				info.cap_offset = 0;
-- 
2.7.4

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