[RFC PATCH 2/6] drm/i915/gvt: OpRegion support for GVT-g

[Xiaoguang Chen <xiaoguang.chen@intel.com>]

OpRegion is needed to support display related operation for
intel vgpu.

A vfio device region is added to intel vgpu to deliver the
host OpRegion information to user space so user space can
construct the OpRegion for vgpu.

Signed-off-by: Bing Niu <bing.niu@intel.com>
Signed-off-by: Xiaoguang Chen <xiaoguang.chen@intel.com>
---
 drivers/gpu/drm/i915/gvt/kvmgt.c    | 97 +++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/gvt/opregion.c | 12 ++++-
 2 files changed, 107 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index 3c6a02b..389f072 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -53,6 +53,8 @@
 #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,
@@ -436,6 +438,92 @@ 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)
+{
+	memunmap(region->data);
+}
+
+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 intel_vgpu_reg_init_opregion(struct intel_vgpu *vgpu)
+{
+	unsigned int addr;
+	void *base;
+	int ret;
+
+	addr = vgpu->gvt->opregion.opregion_pa;
+	if (!addr || !(~addr))
+		return -ENODEV;
+
+	base = memremap(addr, OPREGION_SIZE, MEMREMAP_WB);
+	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);
+	if (ret) {
+		memunmap(base);
+		return ret;
+	}
+
+	return ret;
+}
+
 static int intel_vgpu_create(struct kobject *kobj, struct mdev_device *mdev)
 {
 	struct intel_vgpu *vgpu = NULL;
@@ -467,6 +555,15 @@ static int intel_vgpu_create(struct kobject *kobj, struct mdev_device *mdev)
 	vgpu->vdev.mdev = mdev;
 	mdev_set_drvdata(mdev, vgpu);
 
+	ret = intel_vgpu_reg_init_opregion(vgpu);
+	if (ret) {
+		gvt_vgpu_err("create OpRegion failed\n");
+		goto out;
+	}
+
+	gvt_dbg_core("create OpRegion 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/drivers/gpu/drm/i915/gvt/opregion.c b/drivers/gpu/drm/i915/gvt/opregion.c
index 3117991..99591bc 100644
--- a/drivers/gpu/drm/i915/gvt/opregion.c
+++ b/drivers/gpu/drm/i915/gvt/opregion.c
@@ -283,14 +283,22 @@ int intel_vgpu_emulate_opregion_request(struct intel_vgpu *vgpu, u32 swsci)
 {
 	u32 *scic, *parm;
 	u32 func, subfunc;
+	u32 scic_val, parm_val;
+	u32 gpa;
 
-	scic = vgpu_opregion(vgpu)->va + INTEL_GVT_OPREGION_SCIC;
-	parm = vgpu_opregion(vgpu)->va + INTEL_GVT_OPREGION_PARM;
+	memcpy(&gpa, vgpu_cfg_space(vgpu) + INTEL_GVT_PCI_OPREGION,
+			sizeof(gpa));
+	intel_gvt_hypervisor_read_gpa(vgpu, gpa + INTEL_GVT_OPREGION_SCIC,
+			&scic_val, sizeof(scic_val));
+	intel_gvt_hypervisor_read_gpa(vgpu, gpa + INTEL_GVT_OPREGION_PARM,
+			&parm_val, sizeof(parm_val));
 
 	if (!(swsci & SWSCI_SCI_SELECT)) {
 		gvt_vgpu_err("requesting SMI service\n");
 		return 0;
 	}
+	scic = &scic_val;
+	parm = &parm_val;
 	/* ignore non 0->1 trasitions */
 	if ((vgpu_cfg_space(vgpu)[INTEL_GVT_PCI_SWSCI]
 				& SWSCI_SCI_TRIGGER) ||
-- 
1.9.1