Commit 3a2936de authored May 09, 2018 by Jim Mattson Committed by Paolo Bonzini May 14, 2018

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 <jmattson@google.com>
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

parent 1313cc2b

arch/x86/kvm/mmu.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -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);

Admin message