From: Sean Christopherson Date: Sat, 26 Feb 2022 00:15:20 +0000 (+0000) Subject: KVM: x86/mmu: Check for present SPTE when clearing dirty bit in TDP MMU X-Git-Tag: v5.16.19~158 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c252274fffcfb3bc2d585965cb3a6054e55823da;p=thirdparty%2Fkernel%2Fstable.git KVM: x86/mmu: Check for present SPTE when clearing dirty bit in TDP MMU commit 3354ef5a592d219364cf442c2f784ce7ad7629fd upstream. Explicitly check for present SPTEs when clearing dirty bits in the TDP MMU. This isn't strictly required for correctness, as setting the dirty bit in a defunct SPTE will not change the SPTE from !PRESENT to PRESENT. However, the guarded MMU_WARN_ON() in spte_ad_need_write_protect() would complain if anyone actually turned on KVM's MMU debugging. Fixes: a6a0b05da9f3 ("kvm: x86/mmu: Support dirty logging for the TDP MMU") Cc: Ben Gardon Signed-off-by: Sean Christopherson Reviewed-by: Ben Gardon Message-Id: <20220226001546.360188-3-seanjc@google.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index ea87958ca179f..0f0ec2c33b726 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -1261,6 +1261,9 @@ retry: if (tdp_mmu_iter_cond_resched(kvm, &iter, false, true)) continue; + if (!is_shadow_present_pte(iter.old_spte)) + continue; + if (spte_ad_need_write_protect(iter.old_spte)) { if (is_writable_pte(iter.old_spte)) new_spte = iter.old_spte & ~PT_WRITABLE_MASK;