Messages in this thread | | | Date | Wed, 15 Dec 2021 18:20:31 +0100 | Subject | Re: [PATCH 0/4] KVM: x86/mmu: Zap invalid TDP MMU roots when unmapping | From | Paolo Bonzini <> |
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On 12/15/21 02:15, Sean Christopherson wrote: > Patches 01-03 implement a bug fix by ensuring KVM zaps both valid and > invalid roots when unmapping a gfn range (including the magic "all" range). > Failure to zap invalid roots means KVM doesn't honor the mmu_notifier's > requirement that all references are dropped. > > set_nx_huge_pages() is the most blatant offender, as it doesn't elevate > mm_users and so a VM's entire mm can be released, but the same underlying > bug exists for any "unmap" command from the mmu_notifier in combination > with a memslot update. E.g. if KVM is deleting a memslot, and a > mmu_notifier hook acquires mmu_lock while it's dropped by > kvm_mmu_zap_all_fast(), the mmu_notifier hook will see the to-be-deleted > memslot but won't zap entries from the invalid roots. > > Patch 04 is cleanup to reuse the common iterator for walking _only_ > invalid roots. > > Sean Christopherson (4): > KVM: x86/mmu: Use common TDP MMU zap helper for MMU notifier unmap > hook > KVM: x86/mmu: Move "invalid" check out of kvm_tdp_mmu_get_root() > KVM: x86/mmu: Zap _all_ roots when unmapping gfn range in TDP MMU > KVM: x86/mmu: Use common iterator for walking invalid TDP MMU roots > > arch/x86/kvm/mmu/tdp_mmu.c | 116 +++++++++++++++++-------------------- > arch/x86/kvm/mmu/tdp_mmu.h | 3 - > 2 files changed, 53 insertions(+), 66 deletions(-) >
Queued 1-3 for 5.16 and 4 for 5.17.
Paolo
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