From 0204a49609824163092c32a8aeb073f7e9acc76d Mon Sep 17 00:00:00 2001 From: David Woodhouse Date: Tue, 13 Oct 2015 17:18:10 +0100 Subject: [PATCH] iommu/vt-d: Add callback to device driver on page faults Signed-off-by: David Woodhouse --- drivers/iommu/intel-svm.c | 26 +++++++++++++++++++++++++- include/linux/intel-iommu.h | 3 +++ include/linux/intel-svm.h | 21 ++++++++++++++++++--- 3 files changed, 46 insertions(+), 4 deletions(-) diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c index 0e8654282484..006e95dd64ae 100644 --- a/drivers/iommu/intel-svm.c +++ b/drivers/iommu/intel-svm.c @@ -264,7 +264,7 @@ static const struct mmu_notifier_ops intel_mmuops = { static DEFINE_MUTEX(pasid_mutex); -int intel_svm_bind_mm(struct device *dev, int *pasid) +int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_ops *ops) { struct intel_iommu *iommu = intel_svm_device_to_iommu(dev); struct intel_svm_dev *sdev; @@ -302,6 +302,10 @@ int intel_svm_bind_mm(struct device *dev, int *pasid) list_for_each_entry(sdev, &svm->devs, list) { if (dev == sdev->dev) { + if (sdev->ops != ops) { + ret = -EBUSY; + goto out; + } sdev->users++; goto success; } @@ -327,6 +331,7 @@ int intel_svm_bind_mm(struct device *dev, int *pasid) } /* Finish the setup now we know we're keeping it */ sdev->users = 1; + sdev->ops = ops; init_rcu_head(&sdev->rcu); if (!svm) { @@ -456,6 +461,7 @@ static irqreturn_t prq_event_thread(int irq, void *d) tail = dmar_readq(iommu->reg + DMAR_PQT_REG) & PRQ_RING_MASK; head = dmar_readq(iommu->reg + DMAR_PQH_REG) & PRQ_RING_MASK; while (head != tail) { + struct intel_svm_dev *sdev; struct vm_area_struct *vma; struct page_req_dsc *req; struct qi_desc resp; @@ -507,6 +513,24 @@ static irqreturn_t prq_event_thread(int irq, void *d) up_read(&svm->mm->mmap_sem); bad_req: /* Accounting for major/minor faults? */ + rcu_read_lock(); + list_for_each_entry_rcu(sdev, &svm->devs, list) { + if (sdev->sid == PCI_DEVID(req->bus, req->devfn)); + break; + } + /* Other devices can go away, but the drivers are not permitted + * to unbind while any page faults might be in flight. So it's + * OK to drop the 'lock' here now we have it. */ + rcu_read_unlock(); + + if (WARN_ON(&sdev->list == &svm->devs)) + sdev = NULL; + + if (sdev && sdev->ops && sdev->ops->fault_cb) { + int rwxp = (req->rd_req << 3) | (req->wr_req << 2) | + (req->wr_req << 1) | (req->exe_req); + sdev->ops->fault_cb(sdev->dev, req->pasid, req->addr, req->private, rwxp, result); + } if (req->lpig) { /* Page Group Response */ diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h index e5b80d31eb1b..57be14fce640 100644 --- a/include/linux/intel-iommu.h +++ b/include/linux/intel-iommu.h @@ -472,10 +472,13 @@ extern int intel_svm_free_pasid_tables(struct intel_iommu *iommu); extern int intel_svm_enable_prq(struct intel_iommu *iommu); extern int intel_svm_finish_prq(struct intel_iommu *iommu); +struct svm_dev_ops; + struct intel_svm_dev { struct list_head list; struct rcu_head rcu; struct device *dev; + struct svm_dev_ops *ops; int users; u16 did; u16 dev_iotlb:1; diff --git a/include/linux/intel-svm.h b/include/linux/intel-svm.h index 42f80ad7a7a0..239f8a13a332 100644 --- a/include/linux/intel-svm.h +++ b/include/linux/intel-svm.h @@ -20,10 +20,23 @@ struct device; +struct svm_dev_ops { + void (*fault_cb)(struct device *dev, int pasid, u64 address, + u32 private, int rwxp, int response); +}; + +/* Values for rxwp in fault_cb callback */ +#define SVM_REQ_READ (1<<3) +#define SVM_REQ_WRITE (1<<2) +#define SVM_REQ_EXEC (1<<1) +#define SVM_REQ_PRIV (1<<0) + /** * intel_svm_bind_mm() - Bind the current process to a PASID * @dev: Device to be granted acccess * @pasid: Address for allocated PASID + * @flags: Flags. Later for requesting supervisor mode, etc. + * @ops: Callbacks to device driver * * This function attempts to enable PASID support for the given device. * If the @pasid argument is non-%NULL, a PASID is allocated for access @@ -45,7 +58,8 @@ struct device; * Multiple calls from the same process may result in the same PASID * being re-used. A reference count is kept. */ -extern int intel_svm_bind_mm(struct device *dev, int *pasid); +extern int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, + struct svm_dev_ops *ops); /** * intel_svm_unbind_mm() - Unbind a specified PASID @@ -66,7 +80,8 @@ extern int intel_svm_unbind_mm(struct device *dev, int pasid); #else /* CONFIG_INTEL_IOMMU_SVM */ -static inline int intel_svm_bind_mm(struct device *dev, int *pasid) +static inline int intel_svm_bind_mm(struct device *dev, int *pasid, + int flags, struct svm_dev_ops *ops) { return -ENOSYS; } @@ -77,6 +92,6 @@ static inline int intel_svm_unbind_mm(struct device *dev, int pasid) } #endif /* CONFIG_INTEL_IOMMU_SVM */ -#define intel_svm_available(dev) (!intel_svm_bind_mm((dev), NULL)) +#define intel_svm_available(dev) (!intel_svm_bind_mm((dev), NULL, 0, NULL)) #endif /* __INTEL_SVM_H__ */