Re: [PATCH v2 9/9] iommu/vt-d: Use pci core's DVSEC functionality

Hi Dan,

On 9/29/21 1:54 AM, Dan Williams wrote:

On Thu, Sep 23, 2021 at 10:27 AM Ben Widawsky [off-list ref] wrote:

quoted

Reduce maintenance burden of DVSEC query implementation by using the
centralized PCI core implementation.

Cc: iommu@lists.linux-foundation.org
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Ben Widawsky <redacted>
---
  drivers/iommu/intel/iommu.c | 15 +--------------
  1 file changed, 1 insertion(+), 14 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index d75f59ae28e6..30c97181f0ae 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c

@@ -5398,20 +5398,7 @@ static int intel_iommu_disable_sva(struct device *dev)
   */
  static int siov_find_pci_dvsec(struct pci_dev *pdev)
  {
-       int pos;
-       u16 vendor, id;
-
-       pos = pci_find_next_ext_capability(pdev, 0, 0x23);
-       while (pos) {
-               pci_read_config_word(pdev, pos + 4, &vendor);
-               pci_read_config_word(pdev, pos + 8, &id);
-               if (vendor == PCI_VENDOR_ID_INTEL && id == 5)
-                       return pos;
-
-               pos = pci_find_next_ext_capability(pdev, pos, 0x23);
-       }
-
-       return 0;
+       return pci_find_dvsec_capability(pdev, PCI_VENDOR_ID_INTEL, 5);
  }

Same comments as the CXL patch, siov_find_pci_dvsec() doesn't seem to
have a reason to exist anymore. What is 5?

"5" is DVSEC ID for Scalable IOV.

Anyway, the siov_find_pci_dvsec() has been dead code since commit
262948f8ba57 ("iommu: Delete iommu_dev_has_feature()"). I have a patch
to clean it up. No need to care about it in this series.

Best regards,
baolu