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 <bhelgaas@xxxxxxxxxx>
---
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);
--
To unsubscribe from this list: send the line "unsubscribe linux-pci" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
