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Subject[PATCH v5 02/22] iommu: introduce device fault data
Date
From: Jacob Pan <jacob.jun.pan@linux.intel.com>

Device faults detected by IOMMU can be reported outside the IOMMU
subsystem for further processing. This patch introduces
a generic device fault data structure.

The fault can be either an unrecoverable fault or a page request,
also referred to as a recoverable fault.

We only care about non internal faults that are likely to be reported
to an external subsystem.

Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Signed-off-by: Liu, Yi L <yi.l.liu@linux.intel.com>
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Eric Auger <eric.auger@redhat.com>

---
v4 -> v5:
- simplified struct iommu_fault_event comment
- Moved IOMMU_FAULT_PERM outside of the struct
- Removed IOMMU_FAULT_PERM_INST
- s/IOMMU_FAULT_PAGE_REQUEST_PASID_PRESENT/
IOMMU_FAULT_PAGE_REQUEST_PASID_VALID

v3 -> v4:
- use a union containing aither an unrecoverable fault or a page
request message. Move the device private data in the page request
structure. Reshuffle the fields and use flags.
- move fault perm attributes to the uapi
- remove a bunch of iommu_fault_reason enum values that were related
to internal errors
---
include/linux/iommu.h | 44 ++++++++++++++
include/uapi/linux/iommu.h | 115 +++++++++++++++++++++++++++++++++++++
2 files changed, 159 insertions(+)
create mode 100644 include/uapi/linux/iommu.h

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index ffbbc7e39cee..c6f398f7e6e0 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -25,6 +25,7 @@
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/of.h>
+#include <uapi/linux/iommu.h>

#define IOMMU_READ (1 << 0)
#define IOMMU_WRITE (1 << 1)
@@ -48,6 +49,7 @@ struct bus_type;
struct device;
struct iommu_domain;
struct notifier_block;
+struct iommu_fault_event;

/* iommu fault flags */
#define IOMMU_FAULT_READ 0x0
@@ -55,6 +57,7 @@ struct notifier_block;

typedef int (*iommu_fault_handler_t)(struct iommu_domain *,
struct device *, unsigned long, int, void *);
+typedef int (*iommu_dev_fault_handler_t)(struct iommu_fault_event *, void *);

struct iommu_domain_geometry {
dma_addr_t aperture_start; /* First address that can be mapped */
@@ -247,6 +250,46 @@ struct iommu_device {
struct device *dev;
};

+/**
+ * struct iommu_fault_event - Generic fault event
+ *
+ * Can represent recoverable faults such as a page requests or
+ * unrecoverable faults such as DMA or IRQ remapping faults.
+ *
+ * @fault: fault descriptor
+ * @iommu_private: used by the IOMMU driver for storing fault-specific
+ * data. Users should not modify this field before
+ * sending the fault response.
+ */
+struct iommu_fault_event {
+ struct iommu_fault fault;
+ u64 iommu_private;
+};
+
+/**
+ * struct iommu_fault_param - per-device IOMMU fault data
+ * @dev_fault_handler: Callback function to handle IOMMU faults at device level
+ * @data: handler private data
+ *
+ */
+struct iommu_fault_param {
+ iommu_dev_fault_handler_t handler;
+ void *data;
+};
+
+/**
+ * struct iommu_param - collection of per-device IOMMU data
+ *
+ * @fault_param: IOMMU detected device fault reporting data
+ *
+ * TODO: migrate other per device data pointers under iommu_dev_data, e.g.
+ * struct iommu_group *iommu_group;
+ * struct iommu_fwspec *iommu_fwspec;
+ */
+struct iommu_param {
+ struct iommu_fault_param *fault_param;
+};
+
int iommu_device_register(struct iommu_device *iommu);
void iommu_device_unregister(struct iommu_device *iommu);
int iommu_device_sysfs_add(struct iommu_device *iommu,
@@ -422,6 +465,7 @@ struct iommu_ops {};
struct iommu_group {};
struct iommu_fwspec {};
struct iommu_device {};
+struct iommu_fault_param {};

static inline bool iommu_present(struct bus_type *bus)
{
diff --git a/include/uapi/linux/iommu.h b/include/uapi/linux/iommu.h
new file mode 100644
index 000000000000..edcc0dda7993
--- /dev/null
+++ b/include/uapi/linux/iommu.h
@@ -0,0 +1,115 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * IOMMU user API definitions
+ */
+
+#ifndef _UAPI_IOMMU_H
+#define _UAPI_IOMMU_H
+
+#include <linux/types.h>
+
+#define IOMMU_FAULT_PERM_WRITE (1 << 0) /* write */
+#define IOMMU_FAULT_PERM_EXEC (1 << 1) /* exec */
+#define IOMMU_FAULT_PERM_PRIV (1 << 2) /* privileged */
+
+/* Generic fault types, can be expanded IRQ remapping fault */
+enum iommu_fault_type {
+ IOMMU_FAULT_DMA_UNRECOV = 1, /* unrecoverable fault */
+ IOMMU_FAULT_PAGE_REQ, /* page request fault */
+};
+
+enum iommu_fault_reason {
+ IOMMU_FAULT_REASON_UNKNOWN = 0,
+
+ /* Could not access the PASID table (fetch caused external abort) */
+ IOMMU_FAULT_REASON_PASID_FETCH,
+
+ /* pasid entry is invalid or has configuration errors */
+ IOMMU_FAULT_REASON_BAD_PASID_ENTRY,
+
+ /*
+ * PASID is out of range (e.g. exceeds the maximum PASID
+ * supported by the IOMMU) or disabled.
+ */
+ IOMMU_FAULT_REASON_PASID_INVALID,
+
+ /*
+ * An external abort occurred fetching (or updating) a translation
+ * table descriptor
+ */
+ IOMMU_FAULT_REASON_WALK_EABT,
+
+ /*
+ * Could not access the page table entry (Bad address),
+ * actual translation fault
+ */
+ IOMMU_FAULT_REASON_PTE_FETCH,
+
+ /* Protection flag check failed */
+ IOMMU_FAULT_REASON_PERMISSION,
+
+ /* access flag check failed */
+ IOMMU_FAULT_REASON_ACCESS,
+
+ /* Output address of a translation stage caused Address Size fault */
+ IOMMU_FAULT_REASON_OOR_ADDRESS,
+};
+
+/**
+ * Unrecoverable fault data
+ * @reason: reason of the fault
+ * @addr: offending page address
+ * @fetch_addr: address that caused a fetch abort, if any
+ * @pasid: contains process address space ID, used in shared virtual memory
+ * @perm: Requested permission access using by the incoming transaction
+ * (IOMMU_FAULT_PERM_* values)
+ */
+struct iommu_fault_unrecoverable {
+ __u32 reason; /* enum iommu_fault_reason */
+#define IOMMU_FAULT_UNRECOV_PASID_VALID (1 << 0)
+#define IOMMU_FAULT_UNRECOV_PERM_VALID (1 << 1)
+#define IOMMU_FAULT_UNRECOV_ADDR_VALID (1 << 2)
+#define IOMMU_FAULT_UNRECOV_FETCH_ADDR_VALID (1 << 3)
+ __u32 flags;
+ __u32 pasid;
+ __u32 perm;
+ __u64 addr;
+ __u64 fetch_addr;
+};
+
+/*
+ * Page Request data (aka. recoverable fault data)
+ * @flags : encodes whether the pasid is valid and whether this
+ * is the last page in group
+ * @pasid: pasid
+ * @grpid: page request group index
+ * @perm: requested page permissions (IOMMU_FAULT_PERM_* values)
+ * @addr: page address
+ */
+struct iommu_fault_page_request {
+#define IOMMU_FAULT_PAGE_REQUEST_PASID_VALID (1 << 0)
+#define IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE (1 << 1)
+#define IOMMU_FAULT_PAGE_REQUEST_PRIV_DATA (1 << 2)
+ __u32 flags;
+ __u32 pasid;
+ __u32 grpid;
+ __u32 perm;
+ __u64 addr;
+ __u64 private_data[2];
+};
+
+/**
+ * struct iommu_fault - Generic fault data
+ *
+ * @type contains fault type
+ */
+
+struct iommu_fault {
+ __u32 type; /* enum iommu_fault_type */
+ __u32 reserved;
+ union {
+ struct iommu_fault_unrecoverable event;
+ struct iommu_fault_page_request prm;
+ };
+};
+#endif /* _UAPI_IOMMU_H */
--
2.20.1
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