From 3a2936dedd207b99c64bf1507a62a9ae44114220 Mon Sep 17 00:00:00 2001 From: Jim Mattson Date: Wed, 9 May 2018 17:02:05 -0400 Subject: [PATCH] kvm: mmu: Don't expose private memslots to L2 These private pages have special purposes in the virtualization of L1, but not in the virtualization of L2. In particular, L1's APIC access page should never be entered into L2's page tables, because this causes a great deal of confusion when the APIC virtualization hardware is being used to accelerate L2's accesses to its own APIC. Signed-off-by: Jim Mattson Signed-off-by: Krish Sadhukhan Signed-off-by: Paolo Bonzini --- arch/x86/kvm/mmu.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index ca04766edbd4..8af8c8f88bd7 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -3807,6 +3807,14 @@ static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn, struct kvm_memory_slot *slot; bool async; + /* + * Don't expose private memslots to L2. + */ + if (is_guest_mode(vcpu) && !kvm_is_visible_gfn(vcpu->kvm, gfn)) { + *pfn = KVM_PFN_NOSLOT; + return false; + } + slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn); async = false; *pfn = __gfn_to_pfn_memslot(slot, gfn, false, &async, write, writable); -- 2.11.0