From c583eed6d72bfea853ca7aa645d9295dd2720c6a Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 15 Apr 2020 14:44:13 -0700 Subject: [PATCH] KVM: x86/mmu: Set @writable to false for non-visible accesses by L2 Explicitly set @writable to false in try_async_pf() if the GFN->PFN translation is short-circuited due to the requested GFN not being visible to L2. Leaving @writable ('map_writable' in the callers) uninitialized is ok in that it's never actually consumed, but one has to track it all the way through set_spte() being short-circuited by set_mmio_spte() to understand that the uninitialized variable is benign, and relying on @writable being ignored is an unnecessary risk. Explicitly setting @writable also aligns try_async_pf() with __gfn_to_pfn_memslot(). Jim Mattson Signed-off-by: Sean Christopherson Message-Id: <20200415214414.10194-2-sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/mmu/mmu.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 3385d6d..b67046f 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -4090,6 +4090,7 @@ static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn, */ if (is_guest_mode(vcpu) && !kvm_is_visible_gfn(vcpu->kvm, gfn)) { *pfn = KVM_PFN_NOSLOT; + *writable = false; return false; } -- 2.7.4