GVT-g will create an anonymous fd and a vfio device region to deliver
the fd to QEMU.
QEMU can do ioctl using this fd to query/generate dmabuf on an intel vgpu.

Signed-off-by: Xiaoguang Chen <xiaoguang.c...@intel.com>
---
 drivers/gpu/drm/i915/gvt/gvt.c   |   2 +
 drivers/gpu/drm/i915/gvt/gvt.h   |   2 +
 drivers/gpu/drm/i915/gvt/kvmgt.c | 109 +++++++++++++++++++++++++++++++++++++++
 include/uapi/linux/vfio.h        |   1 +
 4 files changed, 114 insertions(+)

diff --git a/drivers/gpu/drm/i915/gvt/gvt.c b/drivers/gpu/drm/i915/gvt/gvt.c
index 7dea5e5..c266d31 100644
--- a/drivers/gpu/drm/i915/gvt/gvt.c
+++ b/drivers/gpu/drm/i915/gvt/gvt.c
@@ -54,6 +54,8 @@
        .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_generate_dmabuf = intel_vgpu_generate_dmabuf,
 };
 
 /**
diff --git a/drivers/gpu/drm/i915/gvt/gvt.h b/drivers/gpu/drm/i915/gvt/gvt.h
index 763a8c5..2733a69 100644
--- a/drivers/gpu/drm/i915/gvt/gvt.h
+++ b/drivers/gpu/drm/i915/gvt/gvt.h
@@ -467,6 +467,8 @@ 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 *, void *);
+       int (*vgpu_generate_dmabuf)(struct intel_vgpu *, void *);
 };
 
 
diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index 389f072..beb5356 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 +525,106 @@ static int intel_vgpu_reg_init_opregion(struct intel_vgpu 
*vgpu)
        return ret;
 }
 
+static int intel_vgpu_gvtg_mmap(struct file *file, struct vm_area_struct *vma)
+{
+       WARN_ON(1);
+
+       return 0;
+}
+
+static int intel_vgpu_gvtg_release(struct inode *inode, struct file *filp)
+{
+       return 0;
+}
+
+static long intel_vgpu_gvtg_ioctl(struct file *filp,
+               unsigned int ioctl, unsigned long arg)
+{
+       struct intel_vgpu *vgpu = filp->private_data;
+       int minsz;
+       struct intel_vgpu_dmabuf dmabuf;
+       int ret;
+
+       minsz = offsetofend(struct intel_vgpu_dmabuf, y_pos);
+       if (copy_from_user(&dmabuf, (void __user *)arg, minsz))
+               return -EFAULT;
+       if (ioctl == INTEL_VGPU_QUERY_DMABUF)
+               ret = intel_gvt_ops->vgpu_query_dmabuf(vgpu, &dmabuf);
+       else if (ioctl == INTEL_VGPU_GENERATE_DMABUF)
+               ret = intel_gvt_ops->vgpu_generate_dmabuf(vgpu, &dmabuf);
+       else {
+               gvt_vgpu_err("unsupported dmabuf operation\n");
+               return -EINVAL;
+       }
+
+       if (ret != 0) {
+               gvt_vgpu_err("gvt-g get dmabuf failed:%d\n", ret);
+               return -EINVAL;
+       }
+
+       return copy_to_user((void __user *)arg, &dmabuf, minsz) ? -EFAULT : 0;
+}
+
+static const struct file_operations intel_vgpu_gvtg_ops = {
+       .release        = intel_vgpu_gvtg_release,
+       .unlocked_ioctl = intel_vgpu_gvtg_ioctl,
+       .mmap           = intel_vgpu_gvtg_mmap,
+       .llseek         = noop_llseek,
+};
+
+static size_t intel_vgpu_reg_rw_gvtg(struct intel_vgpu *vgpu, char *buf,
+               size_t count, loff_t *ppos, bool iswrite)
+{
+       unsigned int i = VFIO_PCI_OFFSET_TO_INDEX(*ppos) -
+                       VFIO_PCI_NUM_REGIONS;
+       loff_t pos = *ppos & VFIO_PCI_OFFSET_MASK;
+       int fd;
+
+       if (pos >= vgpu->vdev.region[i].size || iswrite) {
+               gvt_vgpu_err("invalid op or offset for Intel vgpu fd region\n");
+               return -EINVAL;
+       }
+
+       fd = anon_inode_getfd("gvtg", &intel_vgpu_gvtg_ops, vgpu,
+                       O_RDWR | O_CLOEXEC);
+       if (fd < 0) {
+               gvt_vgpu_err("create intel vgpu fd failed:%d\n", fd);
+               return -EINVAL;
+       }
+
+       count = min(count, (size_t)(vgpu->vdev.region[i].size - pos));
+       memcpy(buf, &fd, count);
+
+       return count;
+}
+
+static void intel_vgpu_reg_release_gvtg(struct intel_vgpu *vgpu,
+               struct vfio_region *region)
+{
+}
+
+static const struct intel_vgpu_regops intel_vgpu_regops_gvtg = {
+       .rw = intel_vgpu_reg_rw_gvtg,
+       .release = intel_vgpu_reg_release_gvtg,
+};
+
+static int intel_vgpu_reg_init_gvtg(struct intel_vgpu *vgpu)
+{
+       int ret;
+
+       ret = intel_vgpu_register_reg(vgpu,
+               PCI_VENDOR_ID_INTEL | VFIO_REGION_TYPE_PCI_VENDOR_TYPE,
+               VFIO_REGION_SUBTYPE_INTEL_IGD_GVTG,
+               &intel_vgpu_regops_gvtg, sizeof(int),
+               VFIO_REGION_INFO_FLAG_READ, NULL);
+       if (ret) {
+               gvt_vgpu_err("failed to register gvtg region:%d\n", ret);
+               return ret;
+       }
+
+       return ret;
+}
+
 static int intel_vgpu_create(struct kobject *kobj, struct mdev_device *mdev)
 {
        struct intel_vgpu *vgpu = NULL;
@@ -564,6 +665,14 @@ static int intel_vgpu_create(struct kobject *kobj, struct 
mdev_device *mdev)
        gvt_dbg_core("create OpRegion succeeded for mdev:%s\n",
                        dev_name(mdev_dev(mdev)));
 
+       ret = intel_vgpu_reg_init_gvtg(vgpu);
+       if (ret) {
+               gvt_vgpu_err("create gvtg region failed\n");
+               goto out;
+       }
+       gvt_dbg_core("create gvtg region succeeded for mdev:%s\n",
+                       dev_name(mdev_dev(mdev)));
+
        gvt_dbg_core("intel_vgpu_create succeeded for mdev: %s\n",
                     dev_name(mdev_dev(mdev)));
        ret = 0;
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 519eff3..96d2c58 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -297,6 +297,7 @@ struct vfio_region_info_cap_type {
 #define VFIO_REGION_SUBTYPE_INTEL_IGD_OPREGION (1)
 #define VFIO_REGION_SUBTYPE_INTEL_IGD_HOST_CFG (2)
 #define VFIO_REGION_SUBTYPE_INTEL_IGD_LPC_CFG  (3)
+#define VFIO_REGION_SUBTYPE_INTEL_IGD_GVTG     (4)
 
 /**
  * VFIO_DEVICE_GET_IRQ_INFO - _IOWR(VFIO_TYPE, VFIO_BASE + 9,
-- 
1.9.1

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