On 2022/5/13 08:32, Nicolin Chen wrote:
Local boot test and VFIO sanity test show that info->iommu can be
used in device_to_iommu() as a fast path. So this patch adds it.

Signed-off-by: Nicolin Chen <nicol...@nvidia.com>
---
  drivers/iommu/intel/iommu.c | 5 +++++
  1 file changed, 5 insertions(+)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 2990f80c5e08..412fca5ab9cd 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -777,6 +777,7 @@ static bool iommu_is_dummy(struct intel_iommu *iommu, 
struct device *dev)
  struct intel_iommu *device_to_iommu(struct device *dev, u8 *bus, u8 *devfn)
  {
        struct dmar_drhd_unit *drhd = NULL;
+       struct device_domain_info *info;
        struct pci_dev *pdev = NULL;
        struct intel_iommu *iommu;
        struct device *tmp;
@@ -786,6 +787,10 @@ struct intel_iommu *device_to_iommu(struct device *dev, u8 
*bus, u8 *devfn)
        if (!dev)
                return NULL;
+ info = dev_iommu_priv_get(dev);
+       if (info)
+               return info->iommu;

device_to_iommu() also returns device source id (@bus, @devfn).

Perhaps, we can make device_to_iommu() only for probe_device() where the
per-device info data is not initialized yet. After probe_device(), iommu
and sid are retrieved through other helpers by looking up the device
info directly?

Best regards,
baolu

+
        if (dev_is_pci(dev)) {
                struct pci_dev *pf_pdev;

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