[PATCH v6 05/10] iommufd: Add fault and response message definitions

Lu Baolu
2024-05-27T04:08:02Z

iommu_hwpt_pgfaults represent fault messages that the userspace can
retrieve. Multiple iommu_hwpt_pgfaults might be put in an iopf group,
with the IOMMU_PGFAULT_FLAGS_LAST_PAGE flag set only for the last
iommu_hwpt_pgfault.

An iommu_hwpt_page_response is a response message that the userspace
should send to the kernel after finishing handling a group of fault
messages. The @dev_id, @pasid, and @grpid fields in the message
identify an outstanding iopf group for a device. The @cookie field,
which matches the cookie field of the last fault in the group, will
be used by the kernel to look up the pending message.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
include/uapi/linux/iommufd.h | 96 ++++++++++++++++++++++++++++++++++++
1 file changed, 96 insertions(+)

diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index 1dfeaa2e649e..2f34d66436fb 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -692,4 +692,100 @@ struct iommu_hwpt_invalidate {
__u32 __reserved;
};
#define IOMMU_HWPT_INVALIDATE _IO(IOMMUFD_TYPE, IOMMUFD_CMD_HWPT_INVALIDATE)
+
+/**
+ * enum iommu_hwpt_pgfault_flags - flags for struct iommu_hwpt_pgfault
+ * @IOMMU_PGFAULT_FLAGS_PASID_VALID: The pasid field of the fault data is
+ * valid.
+ * @IOMMU_PGFAULT_FLAGS_LAST_PAGE: It's the last fault of a fault group.
+ */
+enum iommu_hwpt_pgfault_flags {
+ IOMMU_PGFAULT_FLAGS_PASID_VALID = (1 << 0),
+ IOMMU_PGFAULT_FLAGS_LAST_PAGE = (1 << 1),
+};
+
+/**
+ * enum iommu_hwpt_pgfault_perm - perm bits for struct iommu_hwpt_pgfault
+ * @IOMMU_PGFAULT_PERM_READ: request for read permission
+ * @IOMMU_PGFAULT_PERM_WRITE: request for write permission
+ * @IOMMU_PGFAULT_PERM_EXEC: (PCIE 10.4.1) request with a PASID that has the
+ * Execute Requested bit set in PASID TLP Prefix.
+ * @IOMMU_PGFAULT_PERM_PRIV: (PCIE 10.4.1) request with a PASID that has the
+ * Privileged Mode Requested bit set in PASID TLP
+ * Prefix.
+ */
+enum iommu_hwpt_pgfault_perm {
+ IOMMU_PGFAULT_PERM_READ = (1 << 0),
+ IOMMU_PGFAULT_PERM_WRITE = (1 << 1),
+ IOMMU_PGFAULT_PERM_EXEC = (1 << 2),
+ IOMMU_PGFAULT_PERM_PRIV = (1 << 3),
+};
+
+/**
+ * struct iommu_hwpt_pgfault - iommu page fault data
+ * @size: sizeof(struct iommu_hwpt_pgfault)
+ * @flags: Combination of enum iommu_hwpt_pgfault_flags
+ * @dev_id: id of the originated device
+ * @pasid: Process Address Space ID
+ * @grpid: Page Request Group Index
+ * @perm: Combination of enum iommu_hwpt_pgfault_perm
+ * @addr: Fault address
+ * @length: a hint of how much data the requestor is expecting to fetch. For
+ * example, if the PRI initiator knows it is going to do a 10MB
+ * transfer, it could fill in 10MB and the OS could pre-fault in
+ * 10MB of IOVA. It's default to 0 if there's no such hint.
+ * @cookie: kernel-managed cookie identifying a group of fault messages. The
+ * cookie number encoded in the last page fault of the group should
+ * be echoed back in the response message.
+ */
+struct iommu_hwpt_pgfault {
+ __u32 size;
+ __u32 flags;
+ __u32 dev_id;
+ __u32 pasid;
+ __u32 grpid;
+ __u32 perm;
+ __u64 addr;
+ __u32 length;
+ __u32 cookie;
+};
+
+/**
+ * enum iommufd_page_response_code - Return status of fault handlers
+ * @IOMMUFD_PAGE_RESP_SUCCESS: Fault has been handled and the page tables
+ * populated, retry the access. This is the
+ * "Success" defined in PCI 10.4.2.1.
+ * @IOMMUFD_PAGE_RESP_INVALID: Could not handle this fault, don't retry the
+ * access. This is the "Invalid Request" in PCI
+ * 10.4.2.1.
+ * @IOMMUFD_PAGE_RESP_FAILURE: General error. Drop all subsequent faults from
+ * this device if possible. This is the "Response
+ * Failure" in PCI 10.4.2.1.
+ */
+enum iommufd_page_response_code {
+ IOMMUFD_PAGE_RESP_SUCCESS = 0,
+ IOMMUFD_PAGE_RESP_INVALID,
+ IOMMUFD_PAGE_RESP_FAILURE,
+};
+
+/**
+ * struct iommu_hwpt_page_response - IOMMU page fault response
+ * @size: sizeof(struct iommu_hwpt_page_response)
+ * @flags: Must be set to 0
+ * @dev_id: device ID of target device for the response
+ * @pasid: Process Address Space ID
+ * @grpid: Page Request Group Index
+ * @code: One of response code in enum iommufd_page_response_code.
+ * @cookie: The kernel-managed cookie reported in the fault message.
+ */
+struct iommu_hwpt_page_response {
+ __u32 size;
+ __u32 flags;
+ __u32 dev_id;
+ __u32 pasid;
+ __u32 grpid;
+ __u32 code;
+ __u32 cookie;
+ __u32 reserved;
+};
#endif
--
2.34.1