Messages in this thread | | | Date | Mon, 19 Feb 2024 14:54:22 +0800 | Subject | Re: [PATCH 2/2] iommu/vt-d: Use device rbtree in iopf reporting path | From | Ethan Zhao <> |
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On 2/15/2024 3:22 PM, Lu Baolu wrote: > 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);
Though per iommu device rbtree isn't a big tree, given already holds spin_lock why still needs irq off ?
Thanks, Ethan
> + 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; > }
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