Messages in this thread Patch in this message | | | From | Lu Baolu <> | Subject | [PATCH 2/2] iommu/vt-d: Use device rbtree in iopf reporting path | Date | Thu, 15 Feb 2024 15:22:49 +0800 |
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The existing IO page fault handler currently locates the PCI device by calling pci_get_domain_bus_and_slot(). This function searches the list of all PCI devices until the desired device is found. To improve lookup efficiency, a helper function named device_rbtree_find() is introduced to search for the device within the rbtree. Replace pci_get_domain_bus_and_slot() in the IO page fault handling path.
Co-developed-by: Huang Jiaqing <jiaqing.huang@intel.com> Signed-off-by: Huang Jiaqing <jiaqing.huang@intel.com> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> --- drivers/iommu/intel/iommu.h | 1 + drivers/iommu/intel/iommu.c | 29 +++++++++++++++++++++++++++++ drivers/iommu/intel/svm.c | 14 ++++++-------- 3 files changed, 36 insertions(+), 8 deletions(-)
diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h index 54eeaa8e35a9..f13c228924f8 100644 --- a/drivers/iommu/intel/iommu.h +++ b/drivers/iommu/intel/iommu.h @@ -1081,6 +1081,7 @@ void free_pgtable_page(void *vaddr); void iommu_flush_write_buffer(struct intel_iommu *iommu); struct iommu_domain *intel_nested_domain_alloc(struct iommu_domain *parent, const struct iommu_user_data *user_data); +struct device *device_rbtree_find(struct intel_iommu *iommu, u16 rid); #ifdef CONFIG_INTEL_IOMMU_SVM void intel_svm_check(struct intel_iommu *iommu); diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index 09009d96e553..d92c680bcc96 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -120,6 +120,35 @@ static int device_rid_cmp(struct rb_node *lhs, const struct rb_node *rhs) return device_rid_cmp_key(&key, rhs); } +/* + * Looks up an IOMMU-probed device using its source ID. + * + * If the device is found: + * - Increments its reference count. + * - Returns a pointer to the device. + * - The caller must call put_device() after using the pointer. + * + * If the device is not found, returns NULL. + */ +struct device *device_rbtree_find(struct intel_iommu *iommu, u16 rid) +{ + struct device_domain_info *info; + struct device *dev = NULL; + struct rb_node *node; + unsigned long flags; + + spin_lock_irqsave(&iommu->device_rbtree_lock, flags); + node = rb_find(&rid, &iommu->device_rbtree, device_rid_cmp_key); + if (node) { + info = rb_entry(node, struct device_domain_info, node); + dev = info->dev; + get_device(dev); + } + spin_unlock_irqrestore(&iommu->device_rbtree_lock, flags); + + return dev; +} + static int device_rbtree_insert(struct intel_iommu *iommu, struct device_domain_info *info) { diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c index b644d57da841..717b7041973c 100644 --- a/drivers/iommu/intel/svm.c +++ b/drivers/iommu/intel/svm.c @@ -645,7 +645,7 @@ static irqreturn_t prq_event_thread(int irq, void *d) struct intel_iommu *iommu = d; struct page_req_dsc *req; int head, tail, handled; - struct pci_dev *pdev; + struct device *dev; u64 address; /* @@ -691,21 +691,19 @@ static irqreturn_t prq_event_thread(int irq, void *d) if (unlikely(req->lpig && !req->rd_req && !req->wr_req)) goto prq_advance; - pdev = pci_get_domain_bus_and_slot(iommu->segment, - PCI_BUS_NUM(req->rid), - req->rid & 0xff); /* * If prq is to be handled outside iommu driver via receiver of * the fault notifiers, we skip the page response here. */ - if (!pdev) + dev = device_rbtree_find(iommu, req->rid); + if (!dev) goto bad_req; - intel_svm_prq_report(iommu, &pdev->dev, req); - trace_prq_report(iommu, &pdev->dev, req->qw_0, req->qw_1, + intel_svm_prq_report(iommu, dev, req); + trace_prq_report(iommu, dev, req->qw_0, req->qw_1, req->priv_data[0], req->priv_data[1], iommu->prq_seq_number++); - pci_dev_put(pdev); + put_device(dev); prq_advance: head = (head + sizeof(*req)) & PRQ_RING_MASK; } -- 2.34.1
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