3 files changed, 39 insertions, 1 deletions
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index c218c89e0e2e..2c41920b641d 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -450,6 +450,16 @@ struct iommu_hwpt_vtd_s1 {
  * nested domain will translate the same as the nesting parent. The S1 will
  * install a Context Descriptor Table pointing at userspace memory translated
  * by the nesting parent.
+ *
+ * It's suggested to allocate a vDEVICE object carrying vSID and then re-attach
+ * the nested domain, as soon as the vSID is available in the VMM level:
+ *
+ * - when Cfg=translate, a vDEVICE must be allocated prior to attaching to the
+ *   allocated nested domain, as CD/ATS invalidations and vevents need a vSID.
+ * - when Cfg=bypass/abort, a vDEVICE is not enforced during the nested domain
+ *   attachment, to support a GBPA case where VM sets CR0.SMMUEN=0. However, if
+ *   VM sets CR0.SMMUEN=1 while missing a vDEVICE object, kernel would fail to
+ *   report events to the VM. E.g. F_TRANSLATION when guest STE.Cfg=abort.
  */
 struct iommu_hwpt_arm_smmuv3 {
 	__aligned_le64 ste[2];
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 75100bf009ba..ac2329f24141 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -14,6 +14,7 @@
 
 #include <linux/types.h>
 #include <linux/ioctl.h>
+#include <linux/stddef.h>
 
 #define VFIO_API_VERSION	0
 
@@ -1478,6 +1479,33 @@ struct vfio_device_feature_bus_master {
 };
 #define VFIO_DEVICE_FEATURE_BUS_MASTER 10
 
+/**
+ * Upon VFIO_DEVICE_FEATURE_GET create a dma_buf fd for the
+ * regions selected.
+ *
+ * open_flags are the typical flags passed to open(2), eg O_RDWR, O_CLOEXEC,
+ * etc. offset/length specify a slice of the region to create the dmabuf from.
+ * nr_ranges is the total number of (P2P DMA) ranges that comprise the dmabuf.
+ *
+ * flags should be 0.
+ *
+ * Return: The fd number on success, -1 and errno is set on failure.
+ */
+#define VFIO_DEVICE_FEATURE_DMA_BUF 11
+
+struct vfio_region_dma_range {
+	__u64 offset;
+	__u64 length;
+};
+
+struct vfio_device_feature_dma_buf {
+	__u32	region_index;
+	__u32	open_flags;
+	__u32   flags;
+	__u32   nr_ranges;
+	struct vfio_region_dma_range dma_ranges[] __counted_by(nr_ranges);
+};
+
 /* -------- API for Type1 VFIO IOMMU -------- */
 
 /**
diff --git a/include/uapi/linux/virtio_pci.h b/include/uapi/linux/virtio_pci.h
index c691ac210ce2..e732e3456e27 100644
--- a/include/uapi/linux/virtio_pci.h
+++ b/include/uapi/linux/virtio_pci.h
@@ -40,7 +40,7 @@
 #define _LINUX_VIRTIO_PCI_H
 
 #include <linux/types.h>
-#include <linux/kernel.h>
+#include <linux/const.h>
 
 #ifndef VIRTIO_PCI_NO_LEGACY