Commit d99ec314 authored by Sean Christopherson's avatar Sean Christopherson Committed by Yu Zhang
Browse files

KVM: x86/mmu: Remove spurious clearing of dirty bit from TDP MMU SPTE 

mainline inclusion
from mainline-v5.13-rc1
commit 6d9aafb9
category: feature
bugzilla: https://gitee.com/openeuler/intel-kernel/issues/I7S3VQ
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6d9aafb96d5f665d038229e7561388c38430b3a8



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Don't clear the dirty bit when aging a TDP MMU SPTE (in response to a MMU
notifier event).  Prematurely clearing the dirty bit could cause spurious
PML updates if aging a page happened to coincide with dirty logging.

Note, tdp_mmu_set_spte_no_acc_track() flows into __handle_changed_spte(),
so the host PFN will be marked dirty, i.e. there is no potential for data
corruption.

Fixes: a6a0b05d ("kvm: x86/mmu: Support dirty logging for the TDP MMU")
Cc: Ben Gardon <bgardon@google.com>
Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Message-Id: <20210331004942.2444916-2-seanjc@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarYu Zhang <yu.c.zhang@linux.intel.com>
parent 36d50151

arch/x86/kvm/mmu/tdp_mmu.c

+0 −1
Original line number Diff line number Diff line
@@ -977,7 +977,6 @@ static int age_gfn_range(struct kvm *kvm, struct kvm_memory_slot *slot, 


			new_spte = mark_spte_for_access_track(new_spte);

		}

		new_spte &= ~shadow_dirty_mask;



		tdp_mmu_set_spte_no_acc_track(kvm, &iter, new_spte);

		young = 1;