2017-10-18 17:31 GMT+08:00 David Hildenbrand <da...@redhat.com>: > On 18.10.2017 03:42, Wanpeng Li wrote: >> From: Wanpeng Li <wanpeng...@hotmail.com> >> >> I can use vmxcap tool to observe "EPTP Switching yes" even if EPT is not >> exposed to L1. >> >> EPT switching is advertised unconditionally since it is emulated, however, >> it can be treated as an extended feature for EPT and it should not be >> advertised if EPT itself is not exposed. This patch fixes it. >> >> Cc: Paolo Bonzini <pbonz...@redhat.com> >> Cc: Radim Krčmář <rkrc...@redhat.com> >> Cc: Jim Mattson <jmatt...@google.com> >> Signed-off-by: Wanpeng Li <wanpeng...@hotmail.com> >> --- >> v2 -> v3: >> * it is legal for the IA32_VMX_VMFUNC MSR to report all-zero >> v1 -> v2: >> * don't advertise "EPT VM Functions" in secondary processor-based >> VM-execution >> controls if we don't actually support any VM Functions. >> >> arch/x86/kvm/vmx.c | 5 +++-- >> 1 file changed, 3 insertions(+), 2 deletions(-) >> >> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c >> index c460b0b..3644540 100644 >> --- a/arch/x86/kvm/vmx.c >> +++ b/arch/x86/kvm/vmx.c >> @@ -2842,8 +2842,9 @@ static void nested_vmx_setup_ctls_msrs(struct vcpu_vmx >> *vmx) >> * Advertise EPTP switching unconditionally >> * since we emulate it >> */ >> - vmx->nested.nested_vmx_vmfunc_controls = >> - VMX_VMFUNC_EPTP_SWITCHING; >> + if (enable_ept) >> + vmx->nested.nested_vmx_vmfunc_controls = >> + VMX_VMFUNC_EPTP_SWITCHING; >> } >> >> /* >> > > I think we talked about how that cannot happen. But you observe it, so > it seems to happen :)
It is very easy to reproduce if you run L1 w/ ept=0. Regards, Wanpeng Li
