[PATCH v5 2/4] vfio: introduce the VFIO_DMA_MAP_FLAG_NOEXEC flag

From: Baptiste Reynal
Date: Wed Mar 04 2015 - 11:08:47 EST


From: Antonios Motakis <a.motakis@xxxxxxxxxxxxxxxxxxxxxx>

We introduce the VFIO_DMA_MAP_FLAG_NOEXEC flag to the VFIO dma map call,
and expose its availability via the capability VFIO_DMA_NOEXEC_IOMMU.
This way the user can control whether the XN flag will be set on the
requested mappings. The IOMMU_NOEXEC flag needs to be available for all
the IOMMUs of the container used.

Signed-off-by: Antonios Motakis <a.motakis@xxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Baptiste Reynal <b.reynal@xxxxxxxxxxxxxxxxxxxxxx>
---
include/uapi/linux/vfio.h | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 5fb3d46..30801a7 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -31,6 +31,7 @@ enum vfio_iommu_cap {
(ex. PCIe NoSnoop stripping) */
VFIO_EEH = 5, /* Check if EEH is supported */
VFIO_TYPE1_NESTING_IOMMU = 6, /* Two-stage IOMMU, implies v2 */
+ VFIO_DMA_NOEXEC_IOMMU = 7,
};


@@ -397,12 +398,17 @@ struct vfio_iommu_type1_info {
*
* Map process virtual addresses to IO virtual addresses using the
* provided struct vfio_dma_map. Caller sets argsz. READ &/ WRITE required.
+ *
+ * To use the VFIO_DMA_MAP_FLAG_NOEXEC flag, the container must support the
+ * VFIO_DMA_NOEXEC_IOMMU capability. If mappings are created using this flag,
+ * any groups subsequently added to the container must support this capability.
*/
struct vfio_iommu_type1_dma_map {
__u32 argsz;
__u32 flags;
#define VFIO_DMA_MAP_FLAG_READ (1 << 0) /* readable from device */
#define VFIO_DMA_MAP_FLAG_WRITE (1 << 1) /* writable from device */
+#define VFIO_DMA_MAP_FLAG_NOEXEC (1 << 2) /* not executable from device */
__u64 vaddr; /* Process virtual address */
__u64 iova; /* IO virtual address */
__u64 size; /* Size of mapping (bytes) */
--
2.3.1

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