Re: [PATCH 1/1] iommu/vt-d: Fix RID2PASID setup failure

On 2022/6/21 10:54, Tian, Kevin wrote:

...

From: Lu Baolu baolu.lu@linux.intel.com Sent: Monday, June 20, 2022 4:17 PM @@ -2564,7 +2564,7 @@ static int domain_add_dev_info(struct dmar_domain *domain, struct device *dev) ret = intel_pasid_setup_second_level(iommu, domain, dev, PASID_RID2PASID); spin_unlock_irqrestore(&iommu->lock, flags);

• if (ret) {
  

• if (ret && ret != -EBUSY) {
  dev_err(dev, "Setup RID2PASID failed\n");
  dmar_remove_one_dev_info(dev);
  return ret;
  

-- 2.25.1

It's cleaner to avoid this error at the first place, i.e. only do the setup when the first device is attached to the pasid table.

The logic that identifies the first device might introduce additional unnecessary complexity. Devices that share a pasid table are rare. I even prefer to give up sharing tables so that the code can be simpler.:-)

-- Best regards, baolu