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Subject[PATCH v9 2/7] iommu/uapi: Add argsz for user filled data
Date
As IOMMU UAPI gets extended, user data size may increase. To support
backward compatibiliy, this patch introduces a size field to each UAPI
data structures. It is *always* the responsibility for the user to fill in
the correct size. Padding fields are adjusted to ensure 8 byte alignment.

Specific scenarios for user data handling are documented in:
Documentation/userspace-api/iommu.rst

As there is no current users of the API, struct version is not
incremented.

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
---
include/uapi/linux/iommu.h | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/include/uapi/linux/iommu.h b/include/uapi/linux/iommu.h
index c2b2caf9ed41..b42acc8fe007 100644
--- a/include/uapi/linux/iommu.h
+++ b/include/uapi/linux/iommu.h
@@ -139,6 +139,7 @@ enum iommu_page_response_code {

/**
* struct iommu_page_response - Generic page response information
+ * @argsz: User filled size of this data
* @version: API version of this structure
* @flags: encodes whether the corresponding fields are valid
* (IOMMU_FAULT_PAGE_RESPONSE_* values)
@@ -147,6 +148,7 @@ enum iommu_page_response_code {
* @code: response code from &enum iommu_page_response_code
*/
struct iommu_page_response {
+ __u32 argsz;
#define IOMMU_PAGE_RESP_VERSION_1 1
__u32 version;
#define IOMMU_PAGE_RESP_PASID_VALID (1 << 0)
@@ -222,6 +224,7 @@ struct iommu_inv_pasid_info {
/**
* struct iommu_cache_invalidate_info - First level/stage invalidation
* information
+ * @argsz: User filled size of this data
* @version: API version of this structure
* @cache: bitfield that allows to select which caches to invalidate
* @granularity: defines the lowest granularity used for the invalidation:
@@ -250,6 +253,7 @@ struct iommu_inv_pasid_info {
* must support the used granularity.
*/
struct iommu_cache_invalidate_info {
+ __u32 argsz;
#define IOMMU_CACHE_INVALIDATE_INFO_VERSION_1 1
__u32 version;
/* IOMMU paging structure cache */
@@ -259,7 +263,7 @@ struct iommu_cache_invalidate_info {
#define IOMMU_CACHE_INV_TYPE_NR (3)
__u8 cache;
__u8 granularity;
- __u8 padding[2];
+ __u8 padding[6];
union {
struct iommu_inv_pasid_info pasid_info;
struct iommu_inv_addr_info addr_info;
@@ -296,6 +300,7 @@ struct iommu_gpasid_bind_data_vtd {

/**
* struct iommu_gpasid_bind_data - Information about device and guest PASID binding
+ * @argsz: User filled size of this data
* @version: Version of this data structure
* @format: PASID table entry format
* @flags: Additional information on guest bind request
@@ -313,17 +318,18 @@ struct iommu_gpasid_bind_data_vtd {
* PASID to host PASID based on this bind data.
*/
struct iommu_gpasid_bind_data {
+ __u32 argsz;
#define IOMMU_GPASID_BIND_VERSION_1 1
__u32 version;
#define IOMMU_PASID_FORMAT_INTEL_VTD 1
__u32 format;
+ __u32 addr_width;
#define IOMMU_SVA_GPASID_VAL (1 << 0) /* guest PASID valid */
__u64 flags;
__u64 gpgd;
__u64 hpasid;
__u64 gpasid;
- __u32 addr_width;
- __u8 padding[12];
+ __u8 padding[8];
/* Vendor specific data */
union {
struct iommu_gpasid_bind_data_vtd vtd;
--
2.7.4
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