Re: [PATCH 8/8] iommu/vt-d: Add set_dev_pasid callback for nested domain

On 11/27/2023 2:34 PM, Yi Liu wrote:

From: Lu Baolu baolu.lu@linux.intel.com

This allows the upper layers to set a nested type domain to a PASID of a device if the PASID feature is supported by the IOMMU hardware.

The set_dev_pasid callback for non-nest domain has already be there, so this only needs to add it for nested domains.

Signed-off-by: Lu Baolu baolu.lu@linux.intel.com Signed-off-by: Yi Liu yi.l.liu@intel.com

---

drivers/iommu/intel/nested.c | 47 ++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+)

diff --git a/drivers/iommu/intel/nested.c b/drivers/iommu/intel/nested.c index 44ad48db7ea0..f6f687750104 100644 --- a/drivers/iommu/intel/nested.c +++ b/drivers/iommu/intel/nested.c @@ -68,6 +68,52 @@ static int intel_nested_attach_dev(struct iommu_domain *domain, return 0; } +static int intel_nested_set_dev_pasid(struct iommu_domain *domain,

• 		      struct device *dev, ioasid_t pasid)
  

+{

• struct device_domain_info *info = dev_iommu_priv_get(dev);
• struct dmar_domain *dmar_domain = to_dmar_domain(domain);
• struct intel_iommu *iommu = info->iommu;
• struct dev_pasid_info *dev_pasid;
• unsigned long flags;
• int ret = 0;
• if (!pasid_supported(iommu))

• return -EOPNOTSUPP;
  

• if (iommu->agaw < dmar_domain->s2_domain->agaw)

• return -EINVAL;
  

• ret = prepare_domain_attach_device(&dmar_domain->s2_domain->domain, dev);
• if (ret)

• return ret;
  

• dev_pasid = kzalloc(sizeof(*dev_pasid), GFP_KERNEL);
• if (!dev_pasid)

• return -ENOMEM;
  

• ret = domain_attach_iommu(dmar_domain, iommu);
• if (ret)

• goto err_free;
  

• ret = intel_pasid_setup_nested(iommu, dev, pasid, dmar_domain);
• if (ret)

• goto err_detach_iommu;
  

• dev_pasid->dev = dev;
• dev_pasid->pasid = pasid;
• spin_lock_irqsave(&dmar_domain->lock, flags);
• list_add(&dev_pasid->link_domain, &dmar_domain->dev_pasids);
• spin_unlock_irqrestore(&dmar_domain->lock, flags);

---> list_add(&dev_pasid->link_domain, &dmar_domain->dev_pasids);

dev_pasid is linked at later time, this leads to domain->has_iotlb_device is not correctly set, which finally results into a missing of device iotlb flush in iommu_flush_dev_iotlb()when it's called. Check this call path: domain_attach_iommu()->domain_update_iommu_cap()->domain_update_iotlb()->domain->has_iotlb_device = has_iotlb_device; The ugly fixup is to call domain_update_iommu_cap() or domain_update_iotlb() here again before return. The similar issue is in intel_iommu_set_dev_pasid() and intel_nested_attach_dev().

• return 0;

+err_detach_iommu:

• domain_detach_iommu(dmar_domain, iommu);

+err_free:

• kfree(dev_pasid);
• return ret;

+}

• static void intel_nested_domain_free(struct iommu_domain *domain) { kfree(to_dmar_domain(domain));

@@ -128,6 +174,7 @@ static int intel_nested_cache_invalidate_user(struct iommu_domain *domain, static const struct iommu_domain_ops intel_nested_domain_ops = { .attach_dev = intel_nested_attach_dev,

• .set_dev_pasid = intel_nested_set_dev_pasid, .free = intel_nested_domain_free, .cache_invalidate_user = intel_nested_cache_invalidate_user, };