From 404381c5839d67aa0c275ad1da96ef3d3928ca2c Mon Sep 17 00:00:00 2001 From: Marcelo Tosatti Date: Mon, 24 Feb 2014 13:59:32 -0300 Subject: [PATCH] KVM: MMU: drop read-only large sptes when creating lower level sptes Read-only large sptes can be created due to read-only faults as follows: - QEMU pagetable entry that maps guest memory is read-only due to COW. - Guest read faults such memory, COW is not broken, because it is a read-only fault. - Enable dirty logging, large spte not nuked because it is read-only. - Write-fault on such memory causes guest to loop endlessly (which must go down to level 1 because dirty logging is enabled). Fix by dropping large spte when necessary. Signed-off-by: Marcelo Tosatti Signed-off-by: Paolo Bonzini --- arch/x86/kvm/mmu.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index e50425d0f5f..9b531351a58 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -2672,6 +2672,7 @@ static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write, break; } + drop_large_spte(vcpu, iterator.sptep); if (!is_shadow_present_pte(*iterator.sptep)) { u64 base_addr = iterator.addr; -- 2.43.2