From 7b367bc9a6415dc6f31135d50ab37e8ee18d6974 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 23 Sep 2020 15:04:22 -0700 Subject: [PATCH] KVM: x86/mmu: Return -EIO if page fault returns RET_PF_INVALID Exit to userspace with an error if the MMU is buggy and returns RET_PF_INVALID when servicing a page fault. This will allow a future patch to invert the emulation path, i.e. emulate only on RET_PF_EMULATE instead of emulating on anything but RET_PF_RETRY. This technically means that KVM will exit to userspace instead of emulating on RET_PF_INVALID, but practically speaking it's a nop as the MMU never returns RET_PF_INVALID. Signed-off-by: Sean Christopherson Message-Id: <20200923220425.18402-2-sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/mmu/mmu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 0db1ca0ba5dfa..68c0a1a374cf8 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -5462,7 +5462,8 @@ int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u64 error_code, if (r == RET_PF_INVALID) { r = kvm_mmu_do_page_fault(vcpu, cr2_or_gpa, lower_32_bits(error_code), false); - WARN_ON(r == RET_PF_INVALID); + if (WARN_ON_ONCE(r == RET_PF_INVALID)) + return -EIO; } if (r == RET_PF_RETRY) -- 2.30.2