Re: [PATCH v3 2/2] iommu/vt-d: don's issue devTLB flush request when device is disconnected

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 




On 12/19/2023 2:57 PM, Baolu Lu wrote:
On 2023/12/19 14:49, Ethan Zhao wrote:
diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
index 74e8e4c17e81..182eb5df244d 100644
--- a/drivers/iommu/intel/pasid.c
+++ b/drivers/iommu/intel/pasid.c
@@ -476,6 +476,23 @@ devtlb_invalidation_with_pasid(struct intel_iommu *iommu,
  {
      struct device_domain_info *info;
      u16 sid, qdep, pfsid;
+    struct pci_dev *pdev;
+
+    pdev = to_pci_dev(dev);
+    if (!pdev)
+        return;
+
+    /*
+     * If endpoint device's link was brough down by user's pci configuration +     * access to it's hotplug capable slot link control register, as sequence +     * response for DLLSC, pciehp_ist() will set the device error_state to +     * pci_channel_io_perm_failure. Checking device's state here to avoid +     * issuing meaningless devTLB flush request to it, that might cause lockup +     * warning or deadlock because too long time waiting in interrupt context.
+     */
+
+    if (pci_dev_is_disconnected(pdev))
+        return;
        info = dev_iommu_priv_get(dev);
      if (!info || !info->ats_enabled)

It's likely better to check the device status after verifying
ats_enabled. How about below change?

diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
index 74e8e4c17e81..fa19c6cdfd8b 100644
--- a/drivers/iommu/intel/pasid.c
+++ b/drivers/iommu/intel/pasid.c
@@ -481,6 +481,9 @@ devtlb_invalidation_with_pasid(struct intel_iommu *iommu,
        if (!info || !info->ats_enabled)
                return;

+       if (pci_dev_is_disconnected(to_pci_dev(dev)))

I like this kind of simplicity, but rationalist always brings me back to the no-error(ugly)

style.  🙂

The rational is that Intel IOMMU driver only supports PCI ATS. So if
device is marked as ATS supported, then it must be a PCI device.
Therefore, it's safe to convert it to pci_device with to_pci_dev().

Fair engough !


Thanks,

Ethan


If you move this up before ATS checking, then you need to check
dev_is_pci().

Best regards,
baolu





[Index of Archives]     [DMA Engine]     [Linux Coverity]     [Linux USB]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [Greybus]

  Powered by Linux