On 2013-05-06 09:04, Jun Nakajima wrote: > Recent KVM, since http://kerneltrap.org/mailarchive/linux-kvm/2010/5/2/6261577 > switch the EFER MSR when EPT is used and the host and guest have different > NX bits. So if we add support for nested EPT (L1 guest using EPT to run L2) > and want to be able to run recent KVM as L1, we need to allow L1 to use this > EFER switching feature. > > To do this EFER switching, KVM uses VM_ENTRY/EXIT_LOAD_IA32_EFER if available, > and if it isn't, it uses the generic VM_ENTRY/EXIT_MSR_LOAD. This patch adds > support for the former (the latter is still unsupported). > > Nested entry and exit emulation (prepare_vmcs_02 and load_vmcs12_host_state, > respectively) already handled VM_ENTRY/EXIT_LOAD_IA32_EFER correctly. So all > that's left to do in this patch is to properly advertise this feature to L1. > > Note that vmcs12's VM_ENTRY/EXIT_LOAD_IA32_EFER are emulated by L0, by using > vmx_set_efer (which itself sets one of several vmcs02 fields), so we always > support this feature, regardless of whether the host supports it. > > Signed-off-by: Nadav Har'El <nyh@xxxxxxxxxx> > Signed-off-by: Jun Nakajima <jun.nakajima@xxxxxxxxx> > Signed-off-by: Xinhao Xu <xinhao.xu@xxxxxxxxx> > --- > arch/x86/kvm/vmx.c | 18 ++++++++++++++---- > 1 file changed, 14 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 867b810..485ded6 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -2057,6 +2057,7 @@ static __init void nested_vmx_setup_ctls_msrs(void) > #else > nested_vmx_exit_ctls_high = 0; > #endif > + nested_vmx_exit_ctls_high |= VM_EXIT_LOAD_IA32_EFER; You are using the wrong baseline. This does not apply against next. Please fix (you can find the properly rebased version in my tree). Thanks, Jan
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