Messages in this thread | | | From | "Liu, Yi L" <> | Subject | RE: [PATCH v3 04/10] iommu/vt-d: Add helper to setup pasid nested translation | Date | Wed, 7 Jun 2023 08:34:22 +0000 |
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> From: Baolu Lu <baolu.lu@linux.intel.com> > Sent: Friday, May 26, 2023 12:16 PM
> >> + > >> + /* First level PGD (in GPA) must be supported by the second level. */ > >> + if ((uintptr_t)s1_gpgd > (1ULL << s2_domain->gaw)) { > >> + dev_err_ratelimited(dev, > >> + "Guest PGD %lx not supported, > >> max %llx\n", > >> + (uintptr_t)s1_gpgd, s2_domain- > >>> max_addr); > >> + return -EINVAL; > >> + } > > > > I'm not sure how useful this check is. Even if the pgd is sane the > > lower level PTEs could include unsupported GPA's. If a guest really > > doesn't want to follow the GPA restriction which vIOMMU reports, > > it can easily cause IOMMU fault in many ways. > > You are right. > > > Then why treating pgd specially? > > I have no memory about this check for now. Yi, any thought?
I don’t think there is another special reason. Just want to ensure the page table base address follows the GPA restriction. But as Kevin mentioned, hw can detect it anyway. So, I think this check can be dropped.
Regards, Yi Liu
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