drm/msm: Add MSM_INFO_GET_FLAGS

In some cases crosvm needs a way to query the cache flags to communicate
them to the guest kernel for guest userspace mapping.
Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/504453/
Link: https://lore.kernel.org/r/20220923173307.2429872-1-robdclark@gmail.comSigned-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

drivers/gpu/drm/msm/msm_drv.c

@@ -819,6 +819,7 @@ static int msm_ioctl_gem_info(struct drm_device *dev, void *data,
 	case MSM_INFO_GET_OFFSET:
 	case MSM_INFO_GET_IOVA:
 	case MSM_INFO_SET_IOVA:
+	case MSM_INFO_GET_FLAGS:
 		/* value returned as immediate, not pointer, so len==0: */
 		if (args->len)
 			return -EINVAL;
@@ -846,6 +847,15 @@ static int msm_ioctl_gem_info(struct drm_device *dev, void *data,
 	case MSM_INFO_SET_IOVA:
 		ret = msm_ioctl_gem_info_set_iova(dev, file, obj, args->value);
 		break;
+	case MSM_INFO_GET_FLAGS:
+		if (obj->import_attach) {
+			ret = -EINVAL;
+			break;
+		}
+		/* Hide internal kernel-only flags: */
+		args->value = to_msm_bo(obj)->flags & MSM_BO_FLAGS;
+		ret = 0;
+		break;
 	case MSM_INFO_SET_NAME:
 		/* length check should leave room for terminating null: */
 		if (args->len >= sizeof(msm_obj->name)) {

include/uapi/drm/msm_drm.h

@@ -138,6 +138,7 @@ struct drm_msm_gem_new {
 #define MSM_INFO_SET_NAME	0x02   /* set the debug name (by pointer) */
 #define MSM_INFO_GET_NAME	0x03   /* get debug name, returned by pointer */
 #define MSM_INFO_SET_IOVA	0x04   /* set the iova, passed by value */
+#define MSM_INFO_GET_FLAGS	0x05   /* get the MSM_BO_x flags */
 
 struct drm_msm_gem_info {
 	__u32 handle;         /* in */