From: Jacob Pan <jacob.jun.pan@linux.intel.com>
To: Joerg Roedel <joro@8bytes.org>,
Alex Williamson <alex.williamson@redhat.com>,
"Lu Baolu" <baolu.lu@linux.intel.com>,
iommu@lists.linux-foundation.org,
LKML <linux-kernel@vger.kernel.org>,
David Woodhouse <dwmw2@infradead.org>,
Jean-Philippe Brucker <jean-philippe@linaro.com>
Cc: "Tian, Kevin" <kevin.tian@intel.com>, Raj Ashok <ashok.raj@intel.com>
Subject: [PATCH v2 3/3] iommu/uapi: Add helper function for size lookup
Date: Wed, 25 Mar 2020 16:17:07 -0700 [thread overview]
Message-ID: <1585178227-17061-4-git-send-email-jacob.jun.pan@linux.intel.com> (raw)
In-Reply-To: <1585178227-17061-1-git-send-email-jacob.jun.pan@linux.intel.com>
IOMMU UAPI can be extended in the future by adding new
fields at the end of each user data structure. Since we use
a unified UAPI version for compatibility checking, a lookup
function is needed to find the correct user data size to copy
from user.
This patch adds a helper function based on a 2D lookup with
version and type as input arguments.
---
v2: Clarify size lookup array extension rules, backfill -EINVAL
if new version introduce new union members.
---
Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
---
drivers/iommu/iommu.c | 72 +++++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/iommu.h | 6 +++++
2 files changed, 78 insertions(+)
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index c476b58e0ffb..e91ced212653 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1724,6 +1724,78 @@ int iommu_sva_unbind_gpasid(struct iommu_domain *domain, struct device *dev,
}
EXPORT_SYMBOL_GPL(iommu_sva_unbind_gpasid);
+
+/**
+ * Maintain a UAPI version to user data structure size lookup for each
+ * API function types we support. e.g. bind guest pasid, cache invalidation.
+ * As data structures being extended with new members, offsetofend() is
+ * used to identify the size. In case of adding a new member to a union,
+ * offsetofend() applies to the largest member which may not be the newest.
+ *
+ * When new types are introduced with new versions, the new types for older
+ * version must be filled with -EINVAL.
+ *
+ * The table below documents UAPI revision history with the name of the
+ * newest member of each data structure. The largest member of a union was
+ * used for the initial version of each type.
+ *
+ * +--------------+---------------+
+ * | Type / | V1 |
+ * | UAPI Version | |
+ * +==============+===============+
+ * | BIND_GPASID | vtd |
+ * +--------------+---------------+
+ * | CACHE_INVAL | addr_info |
+ * +--------------+---------------+
+ * | PAGE_RESP | code |
+ * +--------------+---------------+
+ *
+ * Examples of future extensions:
+ * V2 addes new member to the union
+ * +--------------+---------------+---------------+
+ * | Type / | V1 | V2 |
+ * | UAPI Version | | |
+ * +==============+===============+===============+
+ * | BIND_GPASID | vtd | smmu_v3 |
+ * +--------------+---------------+---------------+
+ * | CACHE_INVAL | addr_info | new_info |
+ * +--------------+---------------+---------------+
+ * | PAGE_RESP | code | N/A |
+ * +--------------+---------------+---------------+
+ *
+ * V3 introduces a new UAPI data type: NEW_TYPE but with no new members
+ * added to the existing types.
+ * +--------------+---------------+---------------+---------------+
+ * | Type / | V1 | V2 | V3 |
+ * | UAPI Version | | | |
+ * +==============+===============+===============+===============+
+ * | BIND_GPASID | vtd | smmu_v3 | N/A |
+ * +--------------+---------------+---------------+---------------+
+ * | CACHE_INVAL | addr_info | new_info | N/A |
+ * +--------------+---------------+---------------+---------------+
+ * | PAGE_RESP | code | N/A | N/A |
+ * +--------------+---------------+---------------+---------------+
+ * | NEW_TYPE | -EINVAL | -EINVAL | largest_member|
+ * +--------------+---------------+---------------+---------------+
+ */
+const static int iommu_uapi_data_size[NR_IOMMU_UAPI_TYPE][IOMMU_UAPI_VERSION] = {
+ /* IOMMU_UAPI_BIND_GPASID */
+ {offsetofend(struct iommu_gpasid_bind_data, vtd)},
+ /* IOMMU_UAPI_CACHE_INVAL */
+ {offsetofend(struct iommu_cache_invalidate_info, addr_info)},
+ /* IOMMU_UAPI_PAGE_RESP */
+ {offsetofend(struct iommu_page_response, code)},
+};
+
+int iommu_uapi_get_data_size(int type, int version)
+{
+ if (type >= NR_IOMMU_UAPI_TYPE || version > IOMMU_UAPI_VERSION)
+ return -EINVAL;
+
+ return iommu_uapi_data_size[type][version - 1];
+}
+EXPORT_SYMBOL_GPL(iommu_uapi_get_data_size);
+
static void __iommu_detach_device(struct iommu_domain *domain,
struct device *dev)
{
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index d1b5f4d98569..4908919a98f1 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -510,6 +510,7 @@ extern int iommu_report_device_fault(struct device *dev,
struct iommu_fault_event *evt);
extern int iommu_page_response(struct device *dev,
struct iommu_page_response *msg);
+extern int iommu_uapi_get_data_size(int type, int version);
extern int iommu_group_id(struct iommu_group *group);
extern struct iommu_group *iommu_group_get_for_dev(struct device *dev);
@@ -897,6 +898,11 @@ static inline int iommu_page_response(struct device *dev,
return -ENODEV;
}
+static inline int iommu_uapi_get_data_size(int type, int version)
+{
+ return -ENODEV;
+}
+
static inline int iommu_group_id(struct iommu_group *group)
{
return -ENODEV;
--
2.7.4
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
prev parent reply other threads:[~2020-03-25 23:11 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-25 23:17 [PATCH v2 0/3] IOMMU user API enhancement Jacob Pan
2020-03-25 23:17 ` [PATCH v2 1/3] iommu/uapi: Define uapi version and capabilities Jacob Pan
2020-03-26 9:23 ` Christoph Hellwig
2020-03-26 16:44 ` Jacob Pan
2020-03-27 2:49 ` Tian, Kevin
2020-03-27 7:47 ` Christoph Hellwig
2020-03-27 23:53 ` Jacob Pan
2020-03-30 5:40 ` Tian, Kevin
2020-03-30 16:07 ` Jacob Pan
2020-03-31 6:06 ` Tian, Kevin
2020-03-31 15:54 ` Jacob Pan
2020-04-01 5:32 ` Tian, Kevin
2020-04-02 18:36 ` Jacob Pan
2020-04-13 20:41 ` Jacob Pan
2020-04-13 22:21 ` Alex Williamson
2020-04-14 5:05 ` Jacob Pan
2020-04-14 16:13 ` Alex Williamson
2020-04-14 17:13 ` Jacob Pan
2020-04-14 22:32 ` Jacob Pan
2020-04-14 23:47 ` Tian, Kevin
2020-04-15 15:38 ` Jacob Pan
2020-04-16 1:27 ` Tian, Kevin
2020-04-14 8:15 ` Christoph Hellwig
2020-04-14 8:11 ` Christoph Hellwig
2020-04-14 16:06 ` Jacob Pan
2020-03-25 23:17 ` [PATCH v2 2/3] iommu/uapi: Use unified UAPI version Jacob Pan
2020-03-25 23:17 ` Jacob Pan [this message]
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