[RFC 6/7] iommu/core: add fault reporting
Ohad Ben-Cohen
ohad at wizery.com
Fri Sep 2 13:32:35 EDT 2011
Add iommu fault report mechanism to the IOMMU API, so implementations
could report about mmu faults (translation errors, hardware errors,
etc..).
Fault reports can be used in several ways:
- mere logging
- reset the device that accessed the faulting address (may be necessary
in case the device is a remote processor for example)
- implement dynamic PTE/TLB loading
Currently the fault handler is installed when allocating a new domain
(less churn for users). Alternatively, we can also add a dedicated
iommu_set_fault_handler() API (presumably with notifiers).
Adopt OMAP's iommu driver (and remove its now-redundant
omap_iommu_set_isr API) and fix existing users of iommu_domain_alloc()
to pass NULL fault handlers.
OMAP's iommu driver will currently only pass the generic IOMMU_ERROR
fault, but in principle we can support dynamic PTE/TLB loading too
in the future.
Signed-off-by: Ohad Ben-Cohen <ohad at wizery.com>
---
arch/arm/plat-omap/include/plat/iommu.h | 3 +-
drivers/iommu/iommu.c | 10 +++++-
drivers/iommu/omap-iommu.c | 31 ++--------------
drivers/media/video/omap3isp/isp.c | 2 +-
include/linux/iommu.h | 60 ++++++++++++++++++++++++++++++-
virt/kvm/iommu.c | 2 +-
6 files changed, 74 insertions(+), 34 deletions(-)
diff --git a/arch/arm/plat-omap/include/plat/iommu.h b/arch/arm/plat-omap/include/plat/iommu.h
index 7f1df0e..a1d79ee 100644
--- a/arch/arm/plat-omap/include/plat/iommu.h
+++ b/arch/arm/plat-omap/include/plat/iommu.h
@@ -32,6 +32,7 @@ struct omap_iommu {
void __iomem *regbase;
struct device *dev;
void *isr_priv;
+ struct iommu_domain *domain;
unsigned int refcount;
spinlock_t iommu_lock; /* global for this whole object */
@@ -48,8 +49,6 @@ struct omap_iommu {
struct list_head mmap;
struct mutex mmap_lock; /* protect mmap */
- int (*isr)(struct omap_iommu *obj, u32 da, u32 iommu_errs, void *priv);
-
void *ctx; /* iommu context: registres saved area */
u32 da_start;
u32 da_end;
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index e61a9ba..c08f1a0 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -40,7 +40,13 @@ bool iommu_found(void)
}
EXPORT_SYMBOL_GPL(iommu_found);
-struct iommu_domain *iommu_domain_alloc(void)
+/**
+ * iommu_domain_alloc() - allocate and initialize a new iommu domain
+ * @handler: an optional pointer to a fault handler, or NULL if not needed
+ *
+ * Returns the new domain, or NULL on error.
+ */
+struct iommu_domain *iommu_domain_alloc(iommu_fault_handler_t handler)
{
struct iommu_domain *domain;
int ret;
@@ -49,6 +55,8 @@ struct iommu_domain *iommu_domain_alloc(void)
if (!domain)
return NULL;
+ domain->handler = handler;
+
ret = iommu_ops->domain_init(domain);
if (ret)
goto out_free;
diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c
index bd5f606..089fddc 100644
--- a/drivers/iommu/omap-iommu.c
+++ b/drivers/iommu/omap-iommu.c
@@ -775,6 +775,7 @@ static irqreturn_t iommu_fault_handler(int irq, void *data)
u32 da, errs;
u32 *iopgd, *iopte;
struct omap_iommu *obj = data;
+ struct iommu_domain *domain = obj->domain;
if (!obj->refcount)
return IRQ_NONE;
@@ -786,7 +787,7 @@ static irqreturn_t iommu_fault_handler(int irq, void *data)
return IRQ_HANDLED;
/* Fault callback or TLB/PTE Dynamic loading */
- if (obj->isr && !obj->isr(obj, da, errs, obj->isr_priv))
+ if (!report_iommu_fault(domain, obj->dev, da, IOMMU_ERROR))
return IRQ_HANDLED;
iommu_disable(obj);
@@ -904,33 +905,6 @@ static void omap_iommu_detach(struct omap_iommu *obj)
dev_dbg(obj->dev, "%s: %s\n", __func__, obj->name);
}
-int omap_iommu_set_isr(const char *name,
- int (*isr)(struct omap_iommu *obj, u32 da, u32 iommu_errs,
- void *priv),
- void *isr_priv)
-{
- struct device *dev;
- struct omap_iommu *obj;
-
- dev = driver_find_device(&omap_iommu_driver.driver, NULL, (void *)name,
- device_match_by_alias);
- if (!dev)
- return -ENODEV;
-
- obj = to_iommu(dev);
- spin_lock(&obj->iommu_lock);
- if (obj->refcount != 0) {
- spin_unlock(&obj->iommu_lock);
- return -EBUSY;
- }
- obj->isr = isr;
- obj->isr_priv = isr_priv;
- spin_unlock(&obj->iommu_lock);
-
- return 0;
-}
-EXPORT_SYMBOL_GPL(omap_iommu_set_isr);
-
/*
* OMAP Device MMU(IOMMU) detection
*/
@@ -1115,6 +1089,7 @@ omap_iommu_attach_dev(struct iommu_domain *domain, struct device *dev)
}
omap_domain->iommu_dev = oiommu;
+ oiommu->domain = domain;
out:
spin_unlock(&omap_domain->lock);
diff --git a/drivers/media/video/omap3isp/isp.c b/drivers/media/video/omap3isp/isp.c
index a4baa61..5b06769 100644
--- a/drivers/media/video/omap3isp/isp.c
+++ b/drivers/media/video/omap3isp/isp.c
@@ -2141,7 +2141,7 @@ static int isp_probe(struct platform_device *pdev)
/* to be removed once iommu migration is complete */
isp->iommu = to_iommu(isp->iommu_dev);
- isp->domain = iommu_domain_alloc();
+ isp->domain = iommu_domain_alloc(NULL);
if (!isp->domain) {
dev_err(isp->dev, "can't alloc iommu domain\n");
ret = -ENOMEM;
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 9940319..3cbea04 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -26,9 +26,27 @@
#define IOMMU_CACHE (4) /* DMA cache coherency */
struct device;
+struct iommu_domain;
+
+/**
+ * enum iommu_fault_types - iommu fault types
+ *
+ * @IOMMU_ERROR: Unrecoverable error
+ * @IOMMU_TLBMISS: TLB miss while the page table walker is disabled
+ * @IOMMU_NOPTE: TLB miss and no PTE for the requested address
+ */
+enum iommu_fault_types {
+ IOMMU_ERROR,
+ IOMMU_TLBMISS,
+ IOMMU_NOPTE,
+};
+
+typedef int (*iommu_fault_handler_t)(struct iommu_domain *,
+ struct device *, unsigned long, int);
struct iommu_domain {
void *priv;
+ iommu_fault_handler_t handler;
};
#define IOMMU_CAP_CACHE_COHERENCY 0x1
@@ -53,7 +71,7 @@ struct iommu_ops {
extern void register_iommu(struct iommu_ops *ops);
extern bool iommu_found(void);
-extern struct iommu_domain *iommu_domain_alloc(void);
+extern struct iommu_domain *iommu_domain_alloc(iommu_fault_handler_t handler);
extern void iommu_domain_free(struct iommu_domain *domain);
extern int iommu_attach_device(struct iommu_domain *domain,
struct device *dev);
@@ -68,6 +86,40 @@ extern phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain,
extern int iommu_domain_has_cap(struct iommu_domain *domain,
unsigned long cap);
+/**
+ * report_iommu_fault() - report about an IOMMU fault to the IOMMU framework
+ * @domain: the iommu domain where the fault has happened
+ * @dev: the device where the fault has happened
+ * @iova: the faulting address
+ * @event: the mmu fault type
+ *
+ * This function should be called by the low-level IOMMU implementations
+ * whenever IOMMU faults happen, to allow high-level users, that are
+ * interested in such events, to know about them.
+ *
+ * This event may be useful in case the device, generating the fault,
+ * needs to be restarted before it can be used again (e.g. this device
+ * may be a remote processor), or if dynamic TLB/PTE loading is desired.
+ *
+ * Returns 0 on success and an appropriate error code otherwise (if dynamic
+ * PTE/TLB loading will one day be supported, implementations will be able
+ * to tell whether it succeeded or not according to this return value).
+ */
+static inline int report_iommu_fault(struct iommu_domain *domain,
+ struct device *dev, unsigned long iova, int event)
+{
+ int ret = 0;
+
+ /*
+ * if upper layers showed interest and installed a fault handler,
+ * invoke it.
+ */
+ if (domain->handler)
+ ret = domain->handler(domain, dev, iova, event);
+
+ return ret;
+}
+
#else /* CONFIG_IOMMU_API */
static inline void register_iommu(struct iommu_ops *ops)
@@ -123,6 +175,12 @@ static inline int domain_has_cap(struct iommu_domain *domain,
return 0;
}
+static inline int report_iommu_fault(struct iommu_domain *domain,
+ struct device *dev, unsigned long iova, int event)
+{
+ return 0;
+}
+
#endif /* CONFIG_IOMMU_API */
#endif /* __LINUX_IOMMU_H */
diff --git a/virt/kvm/iommu.c b/virt/kvm/iommu.c
index 78c80f6..2fd67e5 100644
--- a/virt/kvm/iommu.c
+++ b/virt/kvm/iommu.c
@@ -233,7 +233,7 @@ int kvm_iommu_map_guest(struct kvm *kvm)
return -ENODEV;
}
- kvm->arch.iommu_domain = iommu_domain_alloc();
+ kvm->arch.iommu_domain = iommu_domain_alloc(NULL);
if (!kvm->arch.iommu_domain)
return -ENOMEM;
--
1.7.4.1
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