drm/i915/gvt: expose vGPU context hw id

This exposes vGPU context hw id in mdev sysfs which is used to
do vGPU based profiling. Retrieved vGPU context hw id can be set
through i915 perf ioctl to set profiling for target vGPU.

Cc: Jiao Pengyuan <pengyuan.jiao@intel.com>
Cc: Niu Bing <bing.niu@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

drivers/gpu/drm/i915/gvt/kvmgt.c

@@ -1170,10 +1170,27 @@ vgpu_id_show(struct device *dev, struct device_attribute *attr,
 	return sprintf(buf, "\n");
 }
 
+static ssize_t
+hw_id_show(struct device *dev, struct device_attribute *attr,
+	   char *buf)
+{
+	struct mdev_device *mdev = mdev_from_dev(dev);
+
+	if (mdev) {
+		struct intel_vgpu *vgpu = (struct intel_vgpu *)
+			mdev_get_drvdata(mdev);
+		return sprintf(buf, "%u\n",
+			       vgpu->shadow_ctx->hw_id);
+	}
+	return sprintf(buf, "\n");
+}
+
 static DEVICE_ATTR_RO(vgpu_id);
+static DEVICE_ATTR_RO(hw_id);
 
 static struct attribute *intel_vgpu_attrs[] = {
 	&dev_attr_vgpu_id.attr,
+	&dev_attr_hw_id.attr,
 	NULL
 };