> From: Liu, Yi L <[email protected]> > Sent: Monday, October 9, 2023 4:51 PM > > +struct iommufd_device *iommufd_device_bind_pasid(struct iommufd_ctx > *ictx, > + struct device *dev, > + u32 pasid, u32 *id) > +{ > + struct iommufd_device *idev; > + int rc; > + > + /* > + * iommufd always sets IOMMU_CACHE because we offer no way for > userspace > + * to restore cache coherency. > + */ > + if (!device_iommu_capable(dev, IOMMU_CAP_CACHE_COHERENCY)) > + return ERR_PTR(-EINVAL); > + > + /* > + * No iommu supports pasid-granular msi message today. Here we > + * just check whether the parent device can do safe interrupts. > + * Isolation between virtual devices within the parent device > + * relies on the parent driver to enforce. > + */ > + if (!iommufd_selftest_is_mock_dev(dev) && > + !msi_device_has_isolated_msi(dev)) { > + rc = iommufd_allow_unsafe_interrupts(dev); > + if (rc) > + return ERR_PTR(rc); > + } > +
Only MemWr w/o pasid can be interpreted as an interrupt message then we need msi isolation to protect. But for SIOV all MemWr's are tagged with a pasid hence can never trigger an interrupt. From this angle looks this check is unnecessary.
