[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH for-4.15 3/4] [RFC] xen/iommu: x86: Clear the root page-table before freeing the page-tables
On 23.12.2020 15:56, Julien Grall wrote: > On 23/12/2020 14:12, Jan Beulich wrote: >> On 22.12.2020 16:43, Julien Grall wrote: >>> This is an RFC because it would break AMD IOMMU driver. One option would >>> be to move the call to the teardown callback earlier on. Any opinions? >> >> We already have >> >> static void amd_iommu_domain_destroy(struct domain *d) >> { >> dom_iommu(d)->arch.amd.root_table = NULL; >> } >> >> and this function is AMD's teardown handler. Hence I suppose >> doing the same for VT-d would be quite reasonable. And really >> VT-d's iommu_domain_teardown() also already has >> >> hd->arch.vtd.pgd_maddr = 0; > > Let me have a look if that works. > >> >> I guess what's missing is prevention of the root table >> getting re-setup. > > This is taken care in the follow-up patch by forbidding page-table > allocation. I can mention it in the commit message. My expectation is that with that subsequent change the change here (or any variant of it) would become unnecessary. Jan
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