We check the ATS state (enabled/disabled) and fetch the PCI ATS Invalidate Queue Depth in performance-sensitive paths. It's easy to cache these, which removes dependencies on PCI.
Remember the ATS enabled state. When enabling, read the queue depth once and cache it in the device_domain_info struct. This is similar to what amd_iommu.c does. Signed-off-by: Bjorn Helgaas <[email protected]> --- drivers/iommu/intel-iommu.c | 26 ++++++++++++++++---------- 1 file changed, 16 insertions(+), 10 deletions(-) diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index a98a7b2..50832f1 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -408,6 +408,10 @@ struct device_domain_info { struct list_head global; /* link to global list */ u8 bus; /* PCI bus number */ u8 devfn; /* PCI devfn number */ + struct { + int enabled:1; + u8 qdep; + } ats; /* ATS state */ struct device *dev; /* it's NULL for PCIe-to-PCI bridge */ struct intel_iommu *iommu; /* IOMMU used by this device */ struct dmar_domain *domain; /* pointer to domain */ @@ -1391,19 +1395,26 @@ iommu_support_dev_iotlb (struct dmar_domain *domain, struct intel_iommu *iommu, static void iommu_enable_dev_iotlb(struct device_domain_info *info) { + struct pci_dev *pdev; + if (!info || !dev_is_pci(info->dev)) return; - pci_enable_ats(to_pci_dev(info->dev), VTD_PAGE_SHIFT); + pdev = to_pci_dev(info->dev); + if (pci_enable_ats(pdev, VTD_PAGE_SHIFT)) + return; + + info->ats.enabled = 1; + info->ats.qdep = pci_ats_queue_depth(pdev); } static void iommu_disable_dev_iotlb(struct device_domain_info *info) { - if (!info->dev || !dev_is_pci(info->dev) || - !pci_ats_enabled(to_pci_dev(info->dev))) + if (!info->ats.enabled) return; pci_disable_ats(to_pci_dev(info->dev)); + info->ats.enabled = 0; } static void iommu_flush_dev_iotlb(struct dmar_domain *domain, @@ -1415,16 +1426,11 @@ static void iommu_flush_dev_iotlb(struct dmar_domain *domain, spin_lock_irqsave(&device_domain_lock, flags); list_for_each_entry(info, &domain->devices, link) { - struct pci_dev *pdev; - if (!info->dev || !dev_is_pci(info->dev)) - continue; - - pdev = to_pci_dev(info->dev); - if (!pci_ats_enabled(pdev)) + if (!info->ats.enabled) continue; sid = info->bus << 8 | info->devfn; - qdep = pci_ats_queue_depth(pdev); + qdep = info->ats.qdep; qi_flush_dev_iotlb(info->iommu, sid, qdep, addr, mask); } spin_unlock_irqrestore(&device_domain_lock, flags); _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
