IOMMU user API header was introduced to support nested DMA translation and
related fault handling. The current UAPI data structures consist of three
areas that cover the interactions between host kernel and guest:
- fault handling
- cache invalidation
- bind guest page tables, i.e. guest PASID
Future extensions are likely to support more architectures and vIOMMU features.
In the previous discussion, using user-filled data size and feature flags is
made a preferred approach over a unified version number.
https://lkml.org/lkml/2020/1/29/45
In addition to introduce argsz field to data structures, this patchset is also
trying to document the UAPI design, usage, and extension rules. VT-d driver
changes to utilize the new argsz field is included, VFIO usage is to follow.
This set is available at:
https://github.com/jacobpan/linux.git vsva_v5.9_uapi_v12
Thanks,
Jacob
Changelog:
v12
- Removed a redundant check in cache invalidate API
v11
- Use #define instead of enum in PASID data format, squashed change
into "iommu/uapi: Handle data and argsz filled by users"
- Remove alloc/free from documentation per Yi's comment. IOMMU UAPI
does not perform IOASID alloc/free.
v10
- Documentation grammar fixes based on Randy's review
v9
- Directly pass PASID value to iommu_sva_unbind_gpasid() without
the superfluous data in struct iommu_gpasid_bind_data.
v8
- Rebased to v5.9-rc2
- Addressed review comments from Eric Auger
1. added a check for the unused vendor flags
2. commit message improvements
v7
- Added PASID data format enum for range checking
- Tidy up based on reviews from Alex W.
- Removed doc section for vIOMMU fault handling
v6
- Renamed all UAPI functions with iommu_uapi_ prefix
- Replaced argsz maxsz checking with flag specific size checks
- Documentation improvements based on suggestions by Eric Auger
Replaced example code with a pointer to the actual code
- Added more checks for illegal flags combinations
- Added doc file to MAINTAINERS
v5
- Addjusted paddings in UAPI data to be 8 byte aligned
- Do not clobber argsz in IOMMU core before passing on to vendor driver
- Removed pr_warn_ for invalid UAPI data check, just return -EINVAL
- Clarified VFIO responsibility in UAPI data handling
- Use iommu_uapi prefix to differentiate APIs has in-kernel caller
- Added comment for unchecked flags of invalidation granularity
- Added example in doc to show vendor data checking
v4
- Added checks of UAPI data for reserved fields, version, and flags.
- Removed version check from vendor driver (vt-d)
- Relaxed argsz check to match the UAPI struct size instead of variable
union size
- Updated documentation
v3:
- Rewrote backward compatibility rule to support existing code
re-compiled with newer kernel UAPI header that runs on older
kernel. Based on review comment from Alex W.
https://lore.kernel.org/linux-iommu/[email protected]/
- Take user pointer directly in UAPI functions. Perform argsz check
and copy_from_user() in IOMMU driver. Eliminate the need for
VFIO or other upper layer to parse IOMMU data.
- Create wrapper function for in-kernel users of UAPI functions
v2:
- Removed unified API version and helper
- Introduced argsz for each UAPI data
- Introduced UAPI doc
Jacob Pan (6):
docs: IOMMU user API
iommu/uapi: Add argsz for user filled data
iommu/uapi: Use named union for user data
iommu/uapi: Rename uapi functions
iommu/uapi: Handle data and argsz filled by users
iommu/vt-d: Check UAPI data processed by IOMMU core
Documentation/userspace-api/iommu.rst | 209 ++++++++++++++++++++++++++++++++++
MAINTAINERS | 1 +
drivers/iommu/intel/iommu.c | 25 ++--
drivers/iommu/intel/svm.c | 13 ++-
drivers/iommu/iommu.c | 196 +++++++++++++++++++++++++++++--
include/linux/iommu.h | 35 ++++--
include/uapi/linux/iommu.h | 18 ++-
7 files changed, 456 insertions(+), 41 deletions(-)
create mode 100644 Documentation/userspace-api/iommu.rst
--
2.7.4
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 <[email protected]>
Signed-off-by: Liu Yi L <[email protected]>
Signed-off-by: Jacob Pan <[email protected]>
---
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
User APIs such as iommu_sva_unbind_gpasid() may also be used by the
kernel. Since we introduced user pointer to the UAPI functions,
in-kernel callers cannot share the same APIs. In-kernel callers are also
trusted, there is no need to validate the data.
We plan to have two flavors of the same API functions, one called
through ioctls, carrying a user pointer and one called directly with
valid IOMMU UAPI structs. To differentiate both, let's rename existing
functions with an iommu_uapi_ prefix.
Suggested-by: Alex Williamson <[email protected]>
Reviewed-by: Eric Auger <[email protected]>
Signed-off-by: Jacob Pan <[email protected]>
---
drivers/iommu/iommu.c | 18 +++++++++---------
include/linux/iommu.h | 31 ++++++++++++++++---------------
2 files changed, 25 insertions(+), 24 deletions(-)
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 609bd25bf154..4ae02291ccc2 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1961,35 +1961,35 @@ int iommu_attach_device(struct iommu_domain *domain, struct device *dev)
}
EXPORT_SYMBOL_GPL(iommu_attach_device);
-int iommu_cache_invalidate(struct iommu_domain *domain, struct device *dev,
- struct iommu_cache_invalidate_info *inv_info)
+int iommu_uapi_cache_invalidate(struct iommu_domain *domain, struct device *dev,
+ struct iommu_cache_invalidate_info *inv_info)
{
if (unlikely(!domain->ops->cache_invalidate))
return -ENODEV;
return domain->ops->cache_invalidate(domain, dev, inv_info);
}
-EXPORT_SYMBOL_GPL(iommu_cache_invalidate);
+EXPORT_SYMBOL_GPL(iommu_uapi_cache_invalidate);
-int iommu_sva_bind_gpasid(struct iommu_domain *domain,
- struct device *dev, struct iommu_gpasid_bind_data *data)
+int iommu_uapi_sva_bind_gpasid(struct iommu_domain *domain,
+ struct device *dev, struct iommu_gpasid_bind_data *data)
{
if (unlikely(!domain->ops->sva_bind_gpasid))
return -ENODEV;
return domain->ops->sva_bind_gpasid(domain, dev, data);
}
-EXPORT_SYMBOL_GPL(iommu_sva_bind_gpasid);
+EXPORT_SYMBOL_GPL(iommu_uapi_sva_bind_gpasid);
-int iommu_sva_unbind_gpasid(struct iommu_domain *domain, struct device *dev,
- ioasid_t pasid)
+int iommu_uapi_sva_unbind_gpasid(struct iommu_domain *domain, struct device *dev,
+ ioasid_t pasid)
{
if (unlikely(!domain->ops->sva_unbind_gpasid))
return -ENODEV;
return domain->ops->sva_unbind_gpasid(dev, pasid);
}
-EXPORT_SYMBOL_GPL(iommu_sva_unbind_gpasid);
+EXPORT_SYMBOL_GPL(iommu_uapi_sva_unbind_gpasid);
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 fee209efb756..710d5d2691eb 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -424,13 +424,13 @@ extern int iommu_attach_device(struct iommu_domain *domain,
struct device *dev);
extern void iommu_detach_device(struct iommu_domain *domain,
struct device *dev);
-extern int iommu_cache_invalidate(struct iommu_domain *domain,
- struct device *dev,
- struct iommu_cache_invalidate_info *inv_info);
-extern int iommu_sva_bind_gpasid(struct iommu_domain *domain,
- struct device *dev, struct iommu_gpasid_bind_data *data);
-extern int iommu_sva_unbind_gpasid(struct iommu_domain *domain,
- struct device *dev, ioasid_t pasid);
+extern int iommu_uapi_cache_invalidate(struct iommu_domain *domain,
+ struct device *dev,
+ struct iommu_cache_invalidate_info *inv_info);
+extern int iommu_uapi_sva_bind_gpasid(struct iommu_domain *domain,
+ struct device *dev, struct iommu_gpasid_bind_data *data);
+extern int iommu_uapi_sva_unbind_gpasid(struct iommu_domain *domain,
+ struct device *dev, ioasid_t pasid);
extern struct iommu_domain *iommu_get_domain_for_dev(struct device *dev);
extern struct iommu_domain *iommu_get_dma_domain(struct device *dev);
extern int iommu_map(struct iommu_domain *domain, unsigned long iova,
@@ -1032,21 +1032,22 @@ static inline int iommu_sva_get_pasid(struct iommu_sva *handle)
return IOMMU_PASID_INVALID;
}
-static inline int
-iommu_cache_invalidate(struct iommu_domain *domain,
- struct device *dev,
- struct iommu_cache_invalidate_info *inv_info)
+static inline int iommu_uapi_cache_invalidate(struct iommu_domain *domain,
+ struct device *dev,
+ struct iommu_cache_invalidate_info *inv_info)
{
return -ENODEV;
}
-static inline int iommu_sva_bind_gpasid(struct iommu_domain *domain,
- struct device *dev, struct iommu_gpasid_bind_data *data)
+
+static inline int iommu_uapi_sva_bind_gpasid(struct iommu_domain *domain,
+ struct device *dev,
+ struct iommu_gpasid_bind_data *data)
{
return -ENODEV;
}
-static inline int iommu_sva_unbind_gpasid(struct iommu_domain *domain,
- struct device *dev, int pasid)
+static inline int iommu_uapi_sva_unbind_gpasid(struct iommu_domain *domain,
+ struct device *dev, int pasid)
{
return -ENODEV;
}
--
2.7.4
IOMMU user APIs are responsible for processing user data. This patch
changes the interface such that user pointers can be passed into IOMMU
code directly. Separate kernel APIs without user pointers are introduced
for in-kernel users of the UAPI functionality.
IOMMU UAPI data has a user filled argsz field which indicates the data
length of the structure. User data is not trusted, argsz must be
validated based on the current kernel data size, mandatory data size,
and feature flags.
User data may also be extended, resulting in possible argsz increase.
Backward compatibility is ensured based on size and flags (or
the functional equivalent fields) checking.
This patch adds sanity checks in the IOMMU layer. In addition to argsz,
reserved/unused fields in padding, flags, and version are also checked.
Details are documented in Documentation/userspace-api/iommu.rst
Reviewed-by: Jean-Philippe Brucker <[email protected]>
Signed-off-by: Liu Yi L <[email protected]>
Signed-off-by: Jacob Pan <[email protected]>
---
drivers/iommu/iommu.c | 194 +++++++++++++++++++++++++++++++++++++++++++--
include/linux/iommu.h | 28 ++++---
include/uapi/linux/iommu.h | 1 +
3 files changed, 207 insertions(+), 16 deletions(-)
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 4ae02291ccc2..a11f2733dc54 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1961,34 +1961,214 @@ int iommu_attach_device(struct iommu_domain *domain, struct device *dev)
}
EXPORT_SYMBOL_GPL(iommu_attach_device);
+/*
+ * Check flags and other user provided data for valid combinations. We also
+ * make sure no reserved fields or unused flags are set. This is to ensure
+ * not breaking userspace in the future when these fields or flags are used.
+ */
+static int iommu_check_cache_invl_data(struct iommu_cache_invalidate_info *info)
+{
+ u32 mask;
+ int i;
+
+ if (info->version != IOMMU_CACHE_INVALIDATE_INFO_VERSION_1)
+ return -EINVAL;
+
+ mask = (1 << IOMMU_CACHE_INV_TYPE_NR) - 1;
+ if (info->cache & ~mask)
+ return -EINVAL;
+
+ if (info->granularity >= IOMMU_INV_GRANU_NR)
+ return -EINVAL;
+
+ switch (info->granularity) {
+ case IOMMU_INV_GRANU_ADDR:
+ if (info->cache & IOMMU_CACHE_INV_TYPE_PASID)
+ return -EINVAL;
+
+ mask = IOMMU_INV_ADDR_FLAGS_PASID |
+ IOMMU_INV_ADDR_FLAGS_ARCHID |
+ IOMMU_INV_ADDR_FLAGS_LEAF;
+
+ if (info->granu.addr_info.flags & ~mask)
+ return -EINVAL;
+ break;
+ case IOMMU_INV_GRANU_PASID:
+ mask = IOMMU_INV_PASID_FLAGS_PASID |
+ IOMMU_INV_PASID_FLAGS_ARCHID;
+ if (info->granu.pasid_info.flags & ~mask)
+ return -EINVAL;
+
+ break;
+ case IOMMU_INV_GRANU_DOMAIN:
+ if (info->cache & IOMMU_CACHE_INV_TYPE_DEV_IOTLB)
+ return -EINVAL;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ /* Check reserved padding fields */
+ for (i = 0; i < sizeof(info->padding); i++) {
+ if (info->padding[i])
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
int iommu_uapi_cache_invalidate(struct iommu_domain *domain, struct device *dev,
- struct iommu_cache_invalidate_info *inv_info)
+ void __user *uinfo)
{
+ struct iommu_cache_invalidate_info inv_info = { 0 };
+ u32 minsz;
+ int ret;
+
if (unlikely(!domain->ops->cache_invalidate))
return -ENODEV;
- return domain->ops->cache_invalidate(domain, dev, inv_info);
+ /*
+ * No new spaces can be added before the variable sized union, the
+ * minimum size is the offset to the union.
+ */
+ minsz = offsetof(struct iommu_cache_invalidate_info, granu);
+
+ /* Copy minsz from user to get flags and argsz */
+ if (copy_from_user(&inv_info, uinfo, minsz))
+ return -EFAULT;
+
+ /* Fields before the variable size union are mandatory */
+ if (inv_info.argsz < minsz)
+ return -EINVAL;
+
+ /* PASID and address granu require additional info beyond minsz */
+ if (inv_info.granularity == IOMMU_INV_GRANU_PASID &&
+ inv_info.argsz < offsetofend(struct iommu_cache_invalidate_info, granu.pasid_info))
+ return -EINVAL;
+
+ if (inv_info.granularity == IOMMU_INV_GRANU_ADDR &&
+ inv_info.argsz < offsetofend(struct iommu_cache_invalidate_info, granu.addr_info))
+ return -EINVAL;
+
+ /*
+ * User might be using a newer UAPI header which has a larger data
+ * size, we shall support the existing flags within the current
+ * size. Copy the remaining user data _after_ minsz but not more
+ * than the current kernel supported size.
+ */
+ if (copy_from_user((void *)&inv_info + minsz, uinfo + minsz,
+ min_t(u32, inv_info.argsz, sizeof(inv_info)) - minsz))
+ return -EFAULT;
+
+ /* Now the argsz is validated, check the content */
+ ret = iommu_check_cache_invl_data(&inv_info);
+ if (ret)
+ return ret;
+
+ return domain->ops->cache_invalidate(domain, dev, &inv_info);
}
EXPORT_SYMBOL_GPL(iommu_uapi_cache_invalidate);
-int iommu_uapi_sva_bind_gpasid(struct iommu_domain *domain,
- struct device *dev, struct iommu_gpasid_bind_data *data)
+static int iommu_check_bind_data(struct iommu_gpasid_bind_data *data)
+{
+ u32 mask;
+ int i;
+
+ if (data->version != IOMMU_GPASID_BIND_VERSION_1)
+ return -EINVAL;
+
+ /* Check the range of supported formats */
+ if (data->format >= IOMMU_PASID_FORMAT_LAST)
+ return -EINVAL;
+
+ /* Check all flags */
+ mask = IOMMU_SVA_GPASID_VAL;
+ if (data->flags & ~mask)
+ return -EINVAL;
+
+ /* Check reserved padding fields */
+ for (i = 0; i < sizeof(data->padding); i++) {
+ if (data->padding[i])
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int iommu_sva_prepare_bind_data(void __user *udata,
+ struct iommu_gpasid_bind_data *data)
+{
+ u32 minsz;
+
+ /*
+ * No new spaces can be added before the variable sized union, the
+ * minimum size is the offset to the union.
+ */
+ minsz = offsetof(struct iommu_gpasid_bind_data, vendor);
+
+ /* Copy minsz from user to get flags and argsz */
+ if (copy_from_user(data, udata, minsz))
+ return -EFAULT;
+
+ /* Fields before the variable size union are mandatory */
+ if (data->argsz < minsz)
+ return -EINVAL;
+ /*
+ * User might be using a newer UAPI header, we shall let IOMMU vendor
+ * driver decide on what size it needs. Since the guest PASID bind data
+ * can be vendor specific, larger argsz could be the result of extension
+ * for one vendor but it should not affect another vendor.
+ * Copy the remaining user data _after_ minsz
+ */
+ if (copy_from_user((void *)data + minsz, udata + minsz,
+ min_t(u32, data->argsz, sizeof(*data)) - minsz))
+ return -EFAULT;
+
+ return iommu_check_bind_data(data);
+}
+
+int iommu_uapi_sva_bind_gpasid(struct iommu_domain *domain, struct device *dev,
+ void __user *udata)
{
+ struct iommu_gpasid_bind_data data = { 0 };
+ int ret;
+
if (unlikely(!domain->ops->sva_bind_gpasid))
return -ENODEV;
- return domain->ops->sva_bind_gpasid(domain, dev, data);
+ ret = iommu_sva_prepare_bind_data(udata, &data);
+ if (ret)
+ return ret;
+
+ return domain->ops->sva_bind_gpasid(domain, dev, &data);
}
EXPORT_SYMBOL_GPL(iommu_uapi_sva_bind_gpasid);
-int iommu_uapi_sva_unbind_gpasid(struct iommu_domain *domain, struct device *dev,
- ioasid_t pasid)
+int iommu_sva_unbind_gpasid(struct iommu_domain *domain, struct device *dev,
+ ioasid_t pasid)
{
if (unlikely(!domain->ops->sva_unbind_gpasid))
return -ENODEV;
return domain->ops->sva_unbind_gpasid(dev, pasid);
}
+EXPORT_SYMBOL_GPL(iommu_sva_unbind_gpasid);
+
+int iommu_uapi_sva_unbind_gpasid(struct iommu_domain *domain, struct device *dev,
+ void __user *udata)
+{
+ struct iommu_gpasid_bind_data data = { 0 };
+ int ret;
+
+ if (unlikely(!domain->ops->sva_bind_gpasid))
+ return -ENODEV;
+
+ ret = iommu_sva_prepare_bind_data(udata, &data);
+ if (ret)
+ return ret;
+
+ return iommu_sva_unbind_gpasid(domain, dev, data.hpasid);
+}
EXPORT_SYMBOL_GPL(iommu_uapi_sva_unbind_gpasid);
static void __iommu_detach_device(struct iommu_domain *domain,
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 710d5d2691eb..3ca3a40fc80f 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -426,11 +426,14 @@ extern void iommu_detach_device(struct iommu_domain *domain,
struct device *dev);
extern int iommu_uapi_cache_invalidate(struct iommu_domain *domain,
struct device *dev,
- struct iommu_cache_invalidate_info *inv_info);
+ void __user *uinfo);
+
extern int iommu_uapi_sva_bind_gpasid(struct iommu_domain *domain,
- struct device *dev, struct iommu_gpasid_bind_data *data);
+ struct device *dev, void __user *udata);
extern int iommu_uapi_sva_unbind_gpasid(struct iommu_domain *domain,
- struct device *dev, ioasid_t pasid);
+ struct device *dev, void __user *udata);
+extern int iommu_sva_unbind_gpasid(struct iommu_domain *domain,
+ struct device *dev, ioasid_t pasid);
extern struct iommu_domain *iommu_get_domain_for_dev(struct device *dev);
extern struct iommu_domain *iommu_get_dma_domain(struct device *dev);
extern int iommu_map(struct iommu_domain *domain, unsigned long iova,
@@ -1032,22 +1035,29 @@ static inline int iommu_sva_get_pasid(struct iommu_sva *handle)
return IOMMU_PASID_INVALID;
}
-static inline int iommu_uapi_cache_invalidate(struct iommu_domain *domain,
- struct device *dev,
- struct iommu_cache_invalidate_info *inv_info)
+static inline int
+iommu_uapi_cache_invalidate(struct iommu_domain *domain,
+ struct device *dev,
+ struct iommu_cache_invalidate_info *inv_info)
{
return -ENODEV;
}
static inline int iommu_uapi_sva_bind_gpasid(struct iommu_domain *domain,
- struct device *dev,
- struct iommu_gpasid_bind_data *data)
+ struct device *dev, void __user *udata)
{
return -ENODEV;
}
static inline int iommu_uapi_sva_unbind_gpasid(struct iommu_domain *domain,
- struct device *dev, int pasid)
+ struct device *dev, void __user *udata)
+{
+ return -ENODEV;
+}
+
+static inline int iommu_sva_unbind_gpasid(struct iommu_domain *domain,
+ struct device *dev,
+ ioasid_t pasid)
{
return -ENODEV;
}
diff --git a/include/uapi/linux/iommu.h b/include/uapi/linux/iommu.h
index 5946779ac1f9..66d4ca40b40f 100644
--- a/include/uapi/linux/iommu.h
+++ b/include/uapi/linux/iommu.h
@@ -322,6 +322,7 @@ struct iommu_gpasid_bind_data {
#define IOMMU_GPASID_BIND_VERSION_1 1
__u32 version;
#define IOMMU_PASID_FORMAT_INTEL_VTD 1
+#define IOMMU_PASID_FORMAT_LAST 2
__u32 format;
__u32 addr_width;
#define IOMMU_SVA_GPASID_VAL (1 << 0) /* guest PASID valid */
--
2.7.4
IOMMU UAPI data size is filled by the user space which must be validated
by the kernel. To ensure backward compatibility, user data can only be
extended by either re-purpose padding bytes or extend the variable sized
union at the end. No size change is allowed before the union. Therefore,
the minimum size is the offset of the union.
To use offsetof() on the union, we must make it named.
Link: https://lore.kernel.org/linux-iommu/[email protected]/
Signed-off-by: Jacob Pan <[email protected]>
Reviewed-by: Lu Baolu <[email protected]>
Reviewed-by: Eric Auger <[email protected]>
---
drivers/iommu/intel/iommu.c | 22 +++++++++++-----------
drivers/iommu/intel/svm.c | 2 +-
include/uapi/linux/iommu.h | 4 ++--
3 files changed, 14 insertions(+), 14 deletions(-)
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 87b17bac04c2..461f3a6864d4 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -5434,8 +5434,8 @@ intel_iommu_sva_invalidate(struct iommu_domain *domain, struct device *dev,
/* Size is only valid in address selective invalidation */
if (inv_info->granularity == IOMMU_INV_GRANU_ADDR)
- size = to_vtd_size(inv_info->addr_info.granule_size,
- inv_info->addr_info.nb_granules);
+ size = to_vtd_size(inv_info->granu.addr_info.granule_size,
+ inv_info->granu.addr_info.nb_granules);
for_each_set_bit(cache_type,
(unsigned long *)&inv_info->cache,
@@ -5456,20 +5456,20 @@ intel_iommu_sva_invalidate(struct iommu_domain *domain, struct device *dev,
* granularity.
*/
if (inv_info->granularity == IOMMU_INV_GRANU_PASID &&
- (inv_info->pasid_info.flags & IOMMU_INV_PASID_FLAGS_PASID))
- pasid = inv_info->pasid_info.pasid;
+ (inv_info->granu.pasid_info.flags & IOMMU_INV_PASID_FLAGS_PASID))
+ pasid = inv_info->granu.pasid_info.pasid;
else if (inv_info->granularity == IOMMU_INV_GRANU_ADDR &&
- (inv_info->addr_info.flags & IOMMU_INV_ADDR_FLAGS_PASID))
- pasid = inv_info->addr_info.pasid;
+ (inv_info->granu.addr_info.flags & IOMMU_INV_ADDR_FLAGS_PASID))
+ pasid = inv_info->granu.addr_info.pasid;
switch (BIT(cache_type)) {
case IOMMU_CACHE_INV_TYPE_IOTLB:
/* HW will ignore LSB bits based on address mask */
if (inv_info->granularity == IOMMU_INV_GRANU_ADDR &&
size &&
- (inv_info->addr_info.addr & ((BIT(VTD_PAGE_SHIFT + size)) - 1))) {
+ (inv_info->granu.addr_info.addr & ((BIT(VTD_PAGE_SHIFT + size)) - 1))) {
pr_err_ratelimited("User address not aligned, 0x%llx, size order %llu\n",
- inv_info->addr_info.addr, size);
+ inv_info->granu.addr_info.addr, size);
}
/*
@@ -5477,9 +5477,9 @@ intel_iommu_sva_invalidate(struct iommu_domain *domain, struct device *dev,
* We use npages = -1 to indicate that.
*/
qi_flush_piotlb(iommu, did, pasid,
- mm_to_dma_pfn(inv_info->addr_info.addr),
+ mm_to_dma_pfn(inv_info->granu.addr_info.addr),
(granu == QI_GRAN_NONG_PASID) ? -1 : 1 << size,
- inv_info->addr_info.flags & IOMMU_INV_ADDR_FLAGS_LEAF);
+ inv_info->granu.addr_info.flags & IOMMU_INV_ADDR_FLAGS_LEAF);
if (!info->ats_enabled)
break;
@@ -5502,7 +5502,7 @@ intel_iommu_sva_invalidate(struct iommu_domain *domain, struct device *dev,
size = 64 - VTD_PAGE_SHIFT;
addr = 0;
} else if (inv_info->granularity == IOMMU_INV_GRANU_ADDR) {
- addr = inv_info->addr_info.addr;
+ addr = inv_info->granu.addr_info.addr;
}
if (info->ats_enabled)
diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index 95c3164a2302..99353d6468fa 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -370,7 +370,7 @@ int intel_svm_bind_gpasid(struct iommu_domain *domain, struct device *dev,
spin_lock(&iommu->lock);
ret = intel_pasid_setup_nested(iommu, dev,
(pgd_t *)(uintptr_t)data->gpgd,
- data->hpasid, &data->vtd, dmar_domain,
+ data->hpasid, &data->vendor.vtd, dmar_domain,
data->addr_width);
spin_unlock(&iommu->lock);
if (ret) {
diff --git a/include/uapi/linux/iommu.h b/include/uapi/linux/iommu.h
index b42acc8fe007..5946779ac1f9 100644
--- a/include/uapi/linux/iommu.h
+++ b/include/uapi/linux/iommu.h
@@ -267,7 +267,7 @@ struct iommu_cache_invalidate_info {
union {
struct iommu_inv_pasid_info pasid_info;
struct iommu_inv_addr_info addr_info;
- };
+ } granu;
};
/**
@@ -333,7 +333,7 @@ struct iommu_gpasid_bind_data {
/* Vendor specific data */
union {
struct iommu_gpasid_bind_data_vtd vtd;
- };
+ } vendor;
};
#endif /* _UAPI_IOMMU_H */
--
2.7.4
Hi Joerg,
Just wondering if you will be able to take this for v5.10? There hasn't
been any material changes since we last discussed in LPC. We have VFIO and
other vSVA patches depending on it.
Thanks!
Jacob
On Fri, 25 Sep 2020 09:32:41 -0700, Jacob Pan <[email protected]>
wrote:
> IOMMU user API header was introduced to support nested DMA translation and
> related fault handling. The current UAPI data structures consist of three
> areas that cover the interactions between host kernel and guest:
> - fault handling
> - cache invalidation
> - bind guest page tables, i.e. guest PASID
>
> Future extensions are likely to support more architectures and vIOMMU
> features.
>
> In the previous discussion, using user-filled data size and feature flags
> is made a preferred approach over a unified version number.
> https://lkml.org/lkml/2020/1/29/45
>
> In addition to introduce argsz field to data structures, this patchset is
> also trying to document the UAPI design, usage, and extension rules. VT-d
> driver changes to utilize the new argsz field is included, VFIO usage is
> to follow.
>
> This set is available at:
> https://github.com/jacobpan/linux.git vsva_v5.9_uapi_v12
>
> Thanks,
>
> Jacob
>
>
> Changelog:
> v12
> - Removed a redundant check in cache invalidate API
> v11
> - Use #define instead of enum in PASID data format, squashed
> change into "iommu/uapi: Handle data and argsz filled by users"
> - Remove alloc/free from documentation per Yi's comment. IOMMU
> UAPI does not perform IOASID alloc/free.
> v10
> - Documentation grammar fixes based on Randy's review
> v9
> - Directly pass PASID value to iommu_sva_unbind_gpasid() without
> the superfluous data in struct iommu_gpasid_bind_data.
> v8
> - Rebased to v5.9-rc2
> - Addressed review comments from Eric Auger
> 1. added a check for the unused vendor flags
> 2. commit message improvements
> v7
> - Added PASID data format enum for range checking
> - Tidy up based on reviews from Alex W.
> - Removed doc section for vIOMMU fault handling
> v6
> - Renamed all UAPI functions with iommu_uapi_ prefix
> - Replaced argsz maxsz checking with flag specific size checks
> - Documentation improvements based on suggestions by Eric Auger
> Replaced example code with a pointer to the actual code
> - Added more checks for illegal flags combinations
> - Added doc file to MAINTAINERS
> v5
> - Addjusted paddings in UAPI data to be 8 byte aligned
> - Do not clobber argsz in IOMMU core before passing on to vendor
> driver
> - Removed pr_warn_ for invalid UAPI data check, just return
> -EINVAL
> - Clarified VFIO responsibility in UAPI data handling
> - Use iommu_uapi prefix to differentiate APIs has in-kernel caller
> - Added comment for unchecked flags of invalidation granularity
> - Added example in doc to show vendor data checking
>
> v4
> - Added checks of UAPI data for reserved fields, version, and
> flags.
> - Removed version check from vendor driver (vt-d)
> - Relaxed argsz check to match the UAPI struct size instead of
> variable union size
> - Updated documentation
>
> v3:
> - Rewrote backward compatibility rule to support existing code
> re-compiled with newer kernel UAPI header that runs on older
> kernel. Based on review comment from Alex W.
> https://lore.kernel.org/linux-iommu/[email protected]/
> - Take user pointer directly in UAPI functions. Perform argsz
> check and copy_from_user() in IOMMU driver. Eliminate the need for
> VFIO or other upper layer to parse IOMMU data.
> - Create wrapper function for in-kernel users of UAPI functions
> v2:
> - Removed unified API version and helper
> - Introduced argsz for each UAPI data
> - Introduced UAPI doc
>
>
> Jacob Pan (6):
> docs: IOMMU user API
> iommu/uapi: Add argsz for user filled data
> iommu/uapi: Use named union for user data
> iommu/uapi: Rename uapi functions
> iommu/uapi: Handle data and argsz filled by users
> iommu/vt-d: Check UAPI data processed by IOMMU core
>
> Documentation/userspace-api/iommu.rst | 209
> ++++++++++++++++++++++++++++++++++ MAINTAINERS
> | 1 + drivers/iommu/intel/iommu.c | 25 ++--
> drivers/iommu/intel/svm.c | 13 ++-
> drivers/iommu/iommu.c | 196
> +++++++++++++++++++++++++++++-- include/linux/iommu.h |
> 35 ++++-- include/uapi/linux/iommu.h | 18 ++-
> 7 files changed, 456 insertions(+), 41 deletions(-)
> create mode 100644 Documentation/userspace-api/iommu.rst
>
Thanks,
Jacob
Hi Jacob,
On 9/25/20 6:32 PM, Jacob Pan wrote:
> IOMMU user APIs are responsible for processing user data. This patch
> changes the interface such that user pointers can be passed into IOMMU
> code directly. Separate kernel APIs without user pointers are introduced
> for in-kernel users of the UAPI functionality.
>
> IOMMU UAPI data has a user filled argsz field which indicates the data
> length of the structure. User data is not trusted, argsz must be
> validated based on the current kernel data size, mandatory data size,
> and feature flags.
>
> User data may also be extended, resulting in possible argsz increase.
> Backward compatibility is ensured based on size and flags (or
> the functional equivalent fields) checking.
>
> This patch adds sanity checks in the IOMMU layer. In addition to argsz,
> reserved/unused fields in padding, flags, and version are also checked.
> Details are documented in Documentation/userspace-api/iommu.rst
>
> Reviewed-by: Jean-Philippe Brucker <[email protected]>
> Signed-off-by: Liu Yi L <[email protected]>
> Signed-off-by: Jacob Pan <[email protected]>
Reviewed-by: Eric Auger <[email protected]>
Thanks
Eric
> ---
> drivers/iommu/iommu.c | 194 +++++++++++++++++++++++++++++++++++++++++++--
> include/linux/iommu.h | 28 ++++---
> include/uapi/linux/iommu.h | 1 +
> 3 files changed, 207 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index 4ae02291ccc2..a11f2733dc54 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -1961,34 +1961,214 @@ int iommu_attach_device(struct iommu_domain *domain, struct device *dev)
> }
> EXPORT_SYMBOL_GPL(iommu_attach_device);
>
> +/*
> + * Check flags and other user provided data for valid combinations. We also
> + * make sure no reserved fields or unused flags are set. This is to ensure
> + * not breaking userspace in the future when these fields or flags are used.
> + */
> +static int iommu_check_cache_invl_data(struct iommu_cache_invalidate_info *info)
> +{
> + u32 mask;
> + int i;
> +
> + if (info->version != IOMMU_CACHE_INVALIDATE_INFO_VERSION_1)
> + return -EINVAL;
> +
> + mask = (1 << IOMMU_CACHE_INV_TYPE_NR) - 1;
> + if (info->cache & ~mask)
> + return -EINVAL;
> +
> + if (info->granularity >= IOMMU_INV_GRANU_NR)
> + return -EINVAL;
> +
> + switch (info->granularity) {
> + case IOMMU_INV_GRANU_ADDR:
> + if (info->cache & IOMMU_CACHE_INV_TYPE_PASID)
> + return -EINVAL;
> +
> + mask = IOMMU_INV_ADDR_FLAGS_PASID |
> + IOMMU_INV_ADDR_FLAGS_ARCHID |
> + IOMMU_INV_ADDR_FLAGS_LEAF;
> +
> + if (info->granu.addr_info.flags & ~mask)
> + return -EINVAL;
> + break;
> + case IOMMU_INV_GRANU_PASID:
> + mask = IOMMU_INV_PASID_FLAGS_PASID |
> + IOMMU_INV_PASID_FLAGS_ARCHID;
> + if (info->granu.pasid_info.flags & ~mask)
> + return -EINVAL;
> +
> + break;
> + case IOMMU_INV_GRANU_DOMAIN:
> + if (info->cache & IOMMU_CACHE_INV_TYPE_DEV_IOTLB)
> + return -EINVAL;
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + /* Check reserved padding fields */
> + for (i = 0; i < sizeof(info->padding); i++) {
> + if (info->padding[i])
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> int iommu_uapi_cache_invalidate(struct iommu_domain *domain, struct device *dev,
> - struct iommu_cache_invalidate_info *inv_info)
> + void __user *uinfo)
> {
> + struct iommu_cache_invalidate_info inv_info = { 0 };
> + u32 minsz;
> + int ret;
> +
> if (unlikely(!domain->ops->cache_invalidate))
> return -ENODEV;
>
> - return domain->ops->cache_invalidate(domain, dev, inv_info);
> + /*
> + * No new spaces can be added before the variable sized union, the
> + * minimum size is the offset to the union.
> + */
> + minsz = offsetof(struct iommu_cache_invalidate_info, granu);
> +
> + /* Copy minsz from user to get flags and argsz */
> + if (copy_from_user(&inv_info, uinfo, minsz))
> + return -EFAULT;
> +
> + /* Fields before the variable size union are mandatory */
> + if (inv_info.argsz < minsz)
> + return -EINVAL;
> +
> + /* PASID and address granu require additional info beyond minsz */
> + if (inv_info.granularity == IOMMU_INV_GRANU_PASID &&
> + inv_info.argsz < offsetofend(struct iommu_cache_invalidate_info, granu.pasid_info))
> + return -EINVAL;
> +
> + if (inv_info.granularity == IOMMU_INV_GRANU_ADDR &&
> + inv_info.argsz < offsetofend(struct iommu_cache_invalidate_info, granu.addr_info))
> + return -EINVAL;
> +
> + /*
> + * User might be using a newer UAPI header which has a larger data
> + * size, we shall support the existing flags within the current
> + * size. Copy the remaining user data _after_ minsz but not more
> + * than the current kernel supported size.
> + */
> + if (copy_from_user((void *)&inv_info + minsz, uinfo + minsz,
> + min_t(u32, inv_info.argsz, sizeof(inv_info)) - minsz))
> + return -EFAULT;
> +
> + /* Now the argsz is validated, check the content */
> + ret = iommu_check_cache_invl_data(&inv_info);
> + if (ret)
> + return ret;
> +
> + return domain->ops->cache_invalidate(domain, dev, &inv_info);
> }
> EXPORT_SYMBOL_GPL(iommu_uapi_cache_invalidate);
>
> -int iommu_uapi_sva_bind_gpasid(struct iommu_domain *domain,
> - struct device *dev, struct iommu_gpasid_bind_data *data)
> +static int iommu_check_bind_data(struct iommu_gpasid_bind_data *data)
> +{
> + u32 mask;
> + int i;
> +
> + if (data->version != IOMMU_GPASID_BIND_VERSION_1)
> + return -EINVAL;
> +
> + /* Check the range of supported formats */
> + if (data->format >= IOMMU_PASID_FORMAT_LAST)
> + return -EINVAL;
> +
> + /* Check all flags */
> + mask = IOMMU_SVA_GPASID_VAL;
> + if (data->flags & ~mask)
> + return -EINVAL;
> +
> + /* Check reserved padding fields */
> + for (i = 0; i < sizeof(data->padding); i++) {
> + if (data->padding[i])
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> +static int iommu_sva_prepare_bind_data(void __user *udata,
> + struct iommu_gpasid_bind_data *data)
> +{
> + u32 minsz;
> +
> + /*
> + * No new spaces can be added before the variable sized union, the
> + * minimum size is the offset to the union.
> + */
> + minsz = offsetof(struct iommu_gpasid_bind_data, vendor);
> +
> + /* Copy minsz from user to get flags and argsz */
> + if (copy_from_user(data, udata, minsz))
> + return -EFAULT;
> +
> + /* Fields before the variable size union are mandatory */
> + if (data->argsz < minsz)
> + return -EINVAL;
> + /*
> + * User might be using a newer UAPI header, we shall let IOMMU vendor
> + * driver decide on what size it needs. Since the guest PASID bind data
> + * can be vendor specific, larger argsz could be the result of extension
> + * for one vendor but it should not affect another vendor.
> + * Copy the remaining user data _after_ minsz
> + */
> + if (copy_from_user((void *)data + minsz, udata + minsz,
> + min_t(u32, data->argsz, sizeof(*data)) - minsz))
> + return -EFAULT;
> +
> + return iommu_check_bind_data(data);
> +}
> +
> +int iommu_uapi_sva_bind_gpasid(struct iommu_domain *domain, struct device *dev,
> + void __user *udata)
> {
> + struct iommu_gpasid_bind_data data = { 0 };
> + int ret;
> +
> if (unlikely(!domain->ops->sva_bind_gpasid))
> return -ENODEV;
>
> - return domain->ops->sva_bind_gpasid(domain, dev, data);
> + ret = iommu_sva_prepare_bind_data(udata, &data);
> + if (ret)
> + return ret;
> +
> + return domain->ops->sva_bind_gpasid(domain, dev, &data);
> }
> EXPORT_SYMBOL_GPL(iommu_uapi_sva_bind_gpasid);
>
> -int iommu_uapi_sva_unbind_gpasid(struct iommu_domain *domain, struct device *dev,
> - ioasid_t pasid)
> +int iommu_sva_unbind_gpasid(struct iommu_domain *domain, struct device *dev,
> + ioasid_t pasid)
> {
> if (unlikely(!domain->ops->sva_unbind_gpasid))
> return -ENODEV;
>
> return domain->ops->sva_unbind_gpasid(dev, pasid);
> }
> +EXPORT_SYMBOL_GPL(iommu_sva_unbind_gpasid);
> +
> +int iommu_uapi_sva_unbind_gpasid(struct iommu_domain *domain, struct device *dev,
> + void __user *udata)
> +{
> + struct iommu_gpasid_bind_data data = { 0 };
> + int ret;
> +
> + if (unlikely(!domain->ops->sva_bind_gpasid))
> + return -ENODEV;
> +
> + ret = iommu_sva_prepare_bind_data(udata, &data);
> + if (ret)
> + return ret;
> +
> + return iommu_sva_unbind_gpasid(domain, dev, data.hpasid);
> +}
> EXPORT_SYMBOL_GPL(iommu_uapi_sva_unbind_gpasid);
>
> static void __iommu_detach_device(struct iommu_domain *domain,
> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> index 710d5d2691eb..3ca3a40fc80f 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -426,11 +426,14 @@ extern void iommu_detach_device(struct iommu_domain *domain,
> struct device *dev);
> extern int iommu_uapi_cache_invalidate(struct iommu_domain *domain,
> struct device *dev,
> - struct iommu_cache_invalidate_info *inv_info);
> + void __user *uinfo);
> +
> extern int iommu_uapi_sva_bind_gpasid(struct iommu_domain *domain,
> - struct device *dev, struct iommu_gpasid_bind_data *data);
> + struct device *dev, void __user *udata);
> extern int iommu_uapi_sva_unbind_gpasid(struct iommu_domain *domain,
> - struct device *dev, ioasid_t pasid);
> + struct device *dev, void __user *udata);
> +extern int iommu_sva_unbind_gpasid(struct iommu_domain *domain,
> + struct device *dev, ioasid_t pasid);
> extern struct iommu_domain *iommu_get_domain_for_dev(struct device *dev);
> extern struct iommu_domain *iommu_get_dma_domain(struct device *dev);
> extern int iommu_map(struct iommu_domain *domain, unsigned long iova,
> @@ -1032,22 +1035,29 @@ static inline int iommu_sva_get_pasid(struct iommu_sva *handle)
> return IOMMU_PASID_INVALID;
> }
>
> -static inline int iommu_uapi_cache_invalidate(struct iommu_domain *domain,
> - struct device *dev,
> - struct iommu_cache_invalidate_info *inv_info)
> +static inline int
> +iommu_uapi_cache_invalidate(struct iommu_domain *domain,
> + struct device *dev,
> + struct iommu_cache_invalidate_info *inv_info)
> {
> return -ENODEV;
> }
>
> static inline int iommu_uapi_sva_bind_gpasid(struct iommu_domain *domain,
> - struct device *dev,
> - struct iommu_gpasid_bind_data *data)
> + struct device *dev, void __user *udata)
> {
> return -ENODEV;
> }
>
> static inline int iommu_uapi_sva_unbind_gpasid(struct iommu_domain *domain,
> - struct device *dev, int pasid)
> + struct device *dev, void __user *udata)
> +{
> + return -ENODEV;
> +}
> +
> +static inline int iommu_sva_unbind_gpasid(struct iommu_domain *domain,
> + struct device *dev,
> + ioasid_t pasid)
> {
> return -ENODEV;
> }
> diff --git a/include/uapi/linux/iommu.h b/include/uapi/linux/iommu.h
> index 5946779ac1f9..66d4ca40b40f 100644
> --- a/include/uapi/linux/iommu.h
> +++ b/include/uapi/linux/iommu.h
> @@ -322,6 +322,7 @@ struct iommu_gpasid_bind_data {
> #define IOMMU_GPASID_BIND_VERSION_1 1
> __u32 version;
> #define IOMMU_PASID_FORMAT_INTEL_VTD 1
> +#define IOMMU_PASID_FORMAT_LAST 2
> __u32 format;
> __u32 addr_width;
> #define IOMMU_SVA_GPASID_VAL (1 << 0) /* guest PASID valid */
>
Hi Jacob,
On Mon, Sep 28, 2020 at 11:40:53AM -0700, Jacob Pan wrote:
> Just wondering if you will be able to take this for v5.10? There hasn't
> been any material changes since we last discussed in LPC. We have VFIO and
> other vSVA patches depending on it.
Queued for v5.10 now, thanks.
Regards,
Joerg