[PATCH v4 5/5] drm/i915/gvt: Adding interface so user space can get the dma-buf

[Xiaoguang Chen]

User space will try to create a management fd for the dma-buf operation.
Using this management fd user can query the plane information and create
a dma-buf fd if necessary.
GVT-g will handle the life cycle of the management fd and will align the
life cycle of the fd with the vfio device.
User space should handle the life cycle of the created dma-buf fd close
the dma-buf fd timely when finishing use.

Signed-off-by: Xiaoguang Chen <xiaoguang.chen@xxxxxxxxx>
---
 drivers/gpu/drm/i915/gvt/dmabuf.c | 23 ++++++-----
 drivers/gpu/drm/i915/gvt/dmabuf.h | 22 ----------
 drivers/gpu/drm/i915/gvt/gvt.c    |  2 +
 drivers/gpu/drm/i915/gvt/gvt.h    |  3 ++
 drivers/gpu/drm/i915/gvt/kvmgt.c  | 87 +++++++++++++++++++++++++++++++++++++++
 include/uapi/linux/vfio.h         | 36 ++++++++++++++++
 6 files changed, 140 insertions(+), 33 deletions(-)

diff --git a/drivers/gpu/drm/i915/gvt/dmabuf.c b/drivers/gpu/drm/i915/gvt/dmabuf.c
index c9f283c..c74762f 100644
--- a/drivers/gpu/drm/i915/gvt/dmabuf.c
+++ b/drivers/gpu/drm/i915/gvt/dmabuf.c
@@ -29,6 +29,7 @@
 
 #include <linux/dma-buf.h>
 #include <drm/drmP.h>
+#include <linux/vfio.h>
 
 #include "i915_drv.h"
 #include "gvt.h"
@@ -45,9 +46,9 @@ static struct sg_table *intel_vgpu_gem_get_pages(
 	int i, ret;
 	gen8_pte_t __iomem *gtt_entries;
 	unsigned int fb_gma = 0, fb_size = 0;
-	struct intel_vgpu_plane_info *plane_info;
+	struct plane_info *plane_info;
 
-	plane_info = (struct intel_vgpu_plane_info *)obj->gvt_plane_info;
+	plane_info = (struct plane_info *)obj->gvt_plane_info;
 	if (WARN_ON(!plane_info))
 		return ERR_PTR(-EINVAL);
 
@@ -81,9 +82,9 @@ static struct sg_table *intel_vgpu_gem_get_pages(
 static void intel_vgpu_gem_put_pages(struct drm_i915_gem_object *obj,
 		struct sg_table *pages)
 {
-	struct intel_vgpu_plane_info *plane_info;
+	struct plane_info *plane_info;
 
-	plane_info = (struct intel_vgpu_plane_info *)obj->gvt_plane_info;
+	plane_info = (struct plane_info *)obj->gvt_plane_info;
 	if (WARN_ON(!plane_info))
 		return;
 
@@ -98,7 +99,7 @@ static const struct drm_i915_gem_object_ops intel_vgpu_gem_ops = {
 };
 
 static struct drm_i915_gem_object *intel_vgpu_create_gem(struct drm_device *dev,
-		struct intel_vgpu_plane_info *info)
+		struct plane_info *info)
 {
 	struct drm_i915_private *pri = dev->dev_private;
 	struct drm_i915_gem_object *obj;
@@ -141,14 +142,14 @@ static struct drm_i915_gem_object *intel_vgpu_create_gem(struct drm_device *dev,
 	return obj;
 }
 
-static struct intel_vgpu_plane_info *intel_vgpu_get_plane_info(
+static struct plane_info *intel_vgpu_get_plane_info(
 		struct drm_device *dev,
 		struct intel_vgpu *vgpu, int 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 plane_info *info;
 
 	info = kmalloc(sizeof(*info), GFP_KERNEL);
 	if (!info)
@@ -225,8 +226,8 @@ static struct intel_vgpu_plane_info *intel_vgpu_get_plane_info(
 int intel_vgpu_query_dmabuf(struct intel_vgpu *vgpu, void *args)
 {
 	struct drm_device *dev = &vgpu->gvt->dev_priv->drm;
-	struct intel_vgpu_dmabuf *gvt_dmabuf = args;
-	struct intel_vgpu_plane_info *info;
+	struct dmabuf_info *gvt_dmabuf = args;
+	struct plane_info *info;
 
 	info = intel_vgpu_get_plane_info(dev, vgpu, gvt_dmabuf->plane_id);
 	if (info == NULL)
@@ -242,8 +243,8 @@ 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;
+	struct dmabuf_info *gvt_dmabuf = args;
+	struct plane_info *info;
 	int ret;
 
 	info = intel_vgpu_get_plane_info(dev, vgpu, gvt_dmabuf->plane_id);
diff --git a/drivers/gpu/drm/i915/gvt/dmabuf.h b/drivers/gpu/drm/i915/gvt/dmabuf.h
index c7ce642..0ddea78 100644
--- a/drivers/gpu/drm/i915/gvt/dmabuf.h
+++ b/drivers/gpu/drm/i915/gvt/dmabuf.h
@@ -26,28 +26,6 @@
 #ifndef _GVT_DMABUF_H_
 #define _GVT_DMABUF_H_
 
-struct intel_vgpu_plane_info {
-	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_DMABUF		0
-#define INTEL_VGPU_GENERATE_DMABUF	1
-
-struct intel_vgpu_dmabuf {
-	uint32_t plane_id;
-	/* out */
-	uint32_t fd;
-	struct intel_vgpu_plane_info plane_info;
-};
-
 int intel_vgpu_query_dmabuf(struct intel_vgpu *vgpu, void *args);
 int intel_vgpu_create_dmabuf(struct intel_vgpu *vgpu, void *args);
 
diff --git a/drivers/gpu/drm/i915/gvt/gvt.c b/drivers/gpu/drm/i915/gvt/gvt.c
index 2032917..48e04e6 100644
--- a/drivers/gpu/drm/i915/gvt/gvt.c
+++ b/drivers/gpu/drm/i915/gvt/gvt.c
@@ -54,6 +54,8 @@ static const struct intel_gvt_ops intel_gvt_ops = {
 	.vgpu_reset = intel_gvt_reset_vgpu,
 	.vgpu_activate = intel_gvt_activate_vgpu,
 	.vgpu_deactivate = intel_gvt_deactivate_vgpu,
+	.vgpu_query_dmabuf = intel_vgpu_query_dmabuf,
+	.vgpu_create_dmabuf = intel_vgpu_create_dmabuf,
 };
 
 /**
diff --git a/drivers/gpu/drm/i915/gvt/gvt.h b/drivers/gpu/drm/i915/gvt/gvt.h
index 763a8c5..af843f5 100644
--- a/drivers/gpu/drm/i915/gvt/gvt.h
+++ b/drivers/gpu/drm/i915/gvt/gvt.h
@@ -185,6 +185,7 @@ struct intel_vgpu {
 		struct kvm *kvm;
 		struct work_struct release_work;
 		atomic_t released;
+		struct vfio_device *vfio_device;
 	} vdev;
 #endif
 };
@@ -467,6 +468,8 @@ struct intel_gvt_ops {
 	void (*vgpu_reset)(struct intel_vgpu *);
 	void (*vgpu_activate)(struct intel_vgpu *);
 	void (*vgpu_deactivate)(struct intel_vgpu *);
+	int (*vgpu_query_dmabuf)(struct intel_vgpu *vgpu, void *);
+	int (*vgpu_create_dmabuf)(struct intel_vgpu *vgpu, void *);
 };
 
 
diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index 389f072..6627e8a 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -41,6 +41,7 @@
 #include <linux/kvm_host.h>
 #include <linux/vfio.h>
 #include <linux/mdev.h>
+#include <linux/anon_inodes.h>
 
 #include "i915_drv.h"
 #include "gvt.h"
@@ -524,6 +525,66 @@ static int intel_vgpu_reg_init_opregion(struct intel_vgpu *vgpu)
 	return ret;
 }
 
+static int intel_vgpu_dmabuf_mgr_fd_mmap(struct file *file,
+		struct vm_area_struct *vma)
+{
+	return -EPERM;
+}
+
+static int intel_vgpu_dmabuf_mgr_fd_release(struct inode *inode,
+		struct file *filp)
+{
+	struct intel_vgpu *vgpu = filp->private_data;
+
+	if (WARN_ON(!vgpu->vdev.vfio_device))
+		return -EINVAL;
+
+	vfio_device_put(vgpu->vdev.vfio_device);
+
+	return 0;
+}
+
+static long intel_vgpu_dmabuf_mgr_fd_ioctl(struct file *filp,
+		unsigned int ioctl, unsigned long arg)
+{
+	struct intel_vgpu *vgpu = filp->private_data;
+	int minsz;
+	struct dmabuf_info dmabuf;
+	int ret;
+	struct fd f;
+
+	minsz = offsetofend(struct dmabuf_info, plane_info);
+	if (copy_from_user(&dmabuf, (void __user *)arg, minsz))
+		return -EFAULT;
+
+	f = fdget(dmabuf.fd);
+
+	if (ioctl == VFIO_DEVICE_QUERY_DMABUF)
+		ret = intel_gvt_ops->vgpu_query_dmabuf(vgpu, &dmabuf);
+	else if (ioctl == VFIO_DEVICE_CREATE_DMABUF)
+		ret = intel_gvt_ops->vgpu_create_dmabuf(vgpu, &dmabuf);
+	else {
+		fdput(f);
+		gvt_vgpu_err("unsupported dmabuf operation\n");
+		return -EINVAL;
+	}
+
+	if (ret != 0) {
+		fdput(f);
+		gvt_vgpu_err("gvt-g get dmabuf failed:%d\n", ret);
+		return -EINVAL;
+	}
+	fdput(f);
+
+	return copy_to_user((void __user *)arg, &dmabuf, minsz) ? -EFAULT : 0;
+}
+
+static const struct file_operations intel_vgpu_dmabuf_mgr_fd_ops = {
+	.release        = intel_vgpu_dmabuf_mgr_fd_release,
+	.unlocked_ioctl = intel_vgpu_dmabuf_mgr_fd_ioctl,
+	.mmap           = intel_vgpu_dmabuf_mgr_fd_mmap,
+	.llseek         = noop_llseek,
+};
 static int intel_vgpu_create(struct kobject *kobj, struct mdev_device *mdev)
 {
 	struct intel_vgpu *vgpu = NULL;
@@ -1259,6 +1320,32 @@ static long intel_vgpu_ioctl(struct mdev_device *mdev, unsigned int cmd,
 	} else if (cmd == VFIO_DEVICE_RESET) {
 		intel_gvt_ops->vgpu_reset(vgpu);
 		return 0;
+	} else if (cmd == VFIO_DEVICE_GET_FD) {
+		int fd;
+		u32 type;
+		struct vfio_device *device;
+
+		if (copy_from_user(&type, (void __user *)arg, sizeof(type)))
+			return -EINVAL;
+		if (type != VFIO_DEVICE_DMABUF_MGR_FD)
+			return -EINVAL;
+
+		device = vfio_device_get_from_dev(mdev_dev(mdev));
+		if (device == NULL) {
+			gvt_vgpu_err("kvmgt: vfio device is null\n");
+			return -EINVAL;
+		}
+		vgpu->vdev.vfio_device = device;
+
+		fd = anon_inode_getfd("intel-vgpu-dmabuf-mgr-fd",
+			&intel_vgpu_dmabuf_mgr_fd_ops,
+			vgpu, O_RDWR | O_CLOEXEC);
+		if (fd < 0) {
+			gvt_vgpu_err("create dmabuf mgr fd failed\n");
+			return -EINVAL;
+		}
+
+		return fd;
 	}
 
 	return 0;
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index ae46105..5135e8c 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -502,6 +502,42 @@ struct vfio_pci_hot_reset {
 
 #define VFIO_DEVICE_PCI_HOT_RESET	_IO(VFIO_TYPE, VFIO_BASE + 13)
 
+/**
+ * VFIO_DEVICE_GET_FD - _IO(VFIO_TYPE, VFIO_BASE + 14, __u32)
+ *
+ * Create a fd for a vfio device based on the input type
+ * Vendor driver should handle this ioctl to create a fd and manage the
+ * life cycle of this fd.
+ *
+ * Return: a fd if vendor support that type, -errno if not supported
+ */
+
+struct plane_info {
+	__u32 drm_format;
+	__u32 width;
+	__u32 height;
+	__u32 stride;
+	__u32 start;
+	__u32 x_pos;
+	__u32 y_pos;
+	__u32 size;
+	__u64 drm_format_mod;
+};
+
+struct dmabuf_info {
+	__u32 plane_id;
+	/* out */
+	__u32 fd;
+	struct plane_info plane_info;
+};
+
+#define VFIO_DEVICE_QUERY_DMABUF	0
+#define VFIO_DEVICE_CREATE_DMABUF	1
+
+#define VFIO_DEVICE_DMABUF_MGR_FD	0
+
+#define VFIO_DEVICE_GET_FD	_IO(VFIO_TYPE, VFIO_BASE + 14)
+
 /* -------- API for Type1 VFIO IOMMU -------- */
 
 /**
-- 
2.7.4