drm/i915/gvt: Add opregion support

Windows guest driver needs vbt in opregion, to configure the setting
for display. Without opregion support, the display registers won't
be set and this blocks display model to get the correct information
of the guest display plane.

This patch is to provide a virtual opregion for guest. The original
author of this patch is Xiaoguang Chen.

This patch is split from the "Dma-buf support for GVT-g" patch set,
with being rebased to the latest gvt-staging branch.

v3:
- add checking region index during intel_vgpu_rw. (Xiong)

v2:
- refine intel_vgpu_reg_release_opregion. (Xiong)

Here are the previous version comments:

v18:
- unmap vgpu's opregion when destroying vgpu.

v16:
- rebase to 4.14.0-rc6.

Signed-off-by: Bing Niu <bing.niu@intel.com>
Signed-off-by: Tina Zhang <tina.zhang@intel.com>
Tested-by: Xiong Zhang <xiong.y.zhang@intel.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

1 files changed, 105 insertions, 3 deletions

diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index 110f07e8bcfb..e0cda45ac6c2 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -53,11 +53,23 @@ 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)
 
+#define OPREGION_SIGNATURE "IntelGraphicsMem"
+
+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 {
@@ -316,6 +328,87 @@ static void kvmgt_protect_table_del(struct kvmgt_guest_info *info,
 	}
 }
 
+static size_t intel_vgpu_reg_rw_opregion(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;
+	void *base = vgpu->vdev.region[i].data;
+	loff_t pos = *ppos & VFIO_PCI_OFFSET_MASK;
+
+	if (pos >= vgpu->vdev.region[i].size || iswrite) {
+		gvt_vgpu_err("invalid op or offset for Intel vgpu OpRegion\n");
+		return -EINVAL;
+	}
+	count = min(count, (size_t)(vgpu->vdev.region[i].size - pos));
+	memcpy(buf, base + pos, count);
+
+	return count;
+}
+
+static void intel_vgpu_reg_release_opregion(struct intel_vgpu *vgpu,
+		struct vfio_region *region)
+{
+}
+
+static const struct intel_vgpu_regops intel_vgpu_regops_opregion = {
+	.rw = intel_vgpu_reg_rw_opregion,
+	.release = intel_vgpu_reg_release_opregion,
+};
+
+static int intel_vgpu_register_reg(struct intel_vgpu *vgpu,
+		unsigned int type, unsigned int subtype,
+		const struct intel_vgpu_regops *ops,
+		size_t size, u32 flags, void *data)
+{
+	struct vfio_region *region;
+
+	region = krealloc(vgpu->vdev.region,
+			(vgpu->vdev.num_regions + 1) * sizeof(*region),
+			GFP_KERNEL);
+	if (!region)
+		return -ENOMEM;
+
+	vgpu->vdev.region = region;
+	vgpu->vdev.region[vgpu->vdev.num_regions].type = type;
+	vgpu->vdev.region[vgpu->vdev.num_regions].subtype = subtype;
+	vgpu->vdev.region[vgpu->vdev.num_regions].ops = ops;
+	vgpu->vdev.region[vgpu->vdev.num_regions].size = size;
+	vgpu->vdev.region[vgpu->vdev.num_regions].flags = flags;
+	vgpu->vdev.region[vgpu->vdev.num_regions].data = data;
+	vgpu->vdev.num_regions++;
+
+	return 0;
+}
+
+static int kvmgt_set_opregion(void *p_vgpu)
+{
+	struct intel_vgpu *vgpu = (struct intel_vgpu *)p_vgpu;
+	void *base;
+	int ret;
+
+	/* Each vgpu has its own opregion, although VFIO would create another
+	 * one later. This one is used to expose opregion to VFIO. And the
+	 * other one created by VFIO later, is used by guest actually.
+	 */
+	base = vgpu_opregion(vgpu)->va;
+	if (!base)
+		return -ENOMEM;
+
+	if (memcmp(base, OPREGION_SIGNATURE, 16)) {
+		memunmap(base);
+		return -EINVAL;
+	}
+
+	ret = intel_vgpu_register_reg(vgpu,
+			PCI_VENDOR_ID_INTEL | VFIO_REGION_TYPE_PCI_VENDOR_TYPE,
+			VFIO_REGION_SUBTYPE_INTEL_IGD_OPREGION,
+			&intel_vgpu_regops_opregion, OPREGION_SIZE,
+			VFIO_REGION_INFO_FLAG_READ, base);
+
+	return ret;
+}
+
 static int intel_vgpu_create(struct kobject *kobj, struct mdev_device *mdev)
 {
 	struct intel_vgpu *vgpu = NULL;
@@ -546,7 +639,7 @@ 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;
 	}
@@ -574,8 +667,14 @@ 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);
+		if (index >= VFIO_PCI_NUM_REGIONS + vgpu->vdev.num_regions)
+			return -EINVAL;
+
+		index -= VFIO_PCI_NUM_REGIONS;
+		return vgpu->vdev.region[index].ops->rw(vgpu, buf, count,
+				ppos, is_write);
 	}
 
 	return ret == 0 ? count : ret;
@@ -838,7 +937,8 @@ 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) ?
@@ -959,6 +1059,7 @@ 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;
@@ -1426,6 +1527,7 @@ struct intel_gvt_mpt kvmgt_mpt = {
 	.read_gpa = kvmgt_read_gpa,
 	.write_gpa = kvmgt_write_gpa,
 	.gfn_to_mfn = kvmgt_gfn_to_pfn,
+	.set_opregion = kvmgt_set_opregion,
 };
 EXPORT_SYMBOL_GPL(kvmgt_mpt);