> -----Original Message----- > From: kvm-owner@xxxxxxxxxxxxxxx [mailto:kvm-owner@xxxxxxxxxxxxxxx] On > Behalf Of Jan Kiszka > Sent: Friday, March 28, 2014 12:15 AM > To: Wu, Feng; pbonzini@xxxxxxxxxx; gleb@xxxxxxxxxx; hpa@xxxxxxxxx; > kvm@xxxxxxxxxxxxxxx > Subject: Re: [PATCH 4/4] KVM: Disable SMAP for guests in EPT realmode and > EPT unpaging mode > > On 2014-03-27 13:25, Feng Wu wrote: > > SMAP is disabled if CPU is in non-paging mode in hardware. > > However KVM always uses paging mode to emulate guest non-paging > > mode with TDP. To emulate this behavior, SMAP needs to be > > manually disabled when guest switches to non-paging mode. > > > > Signed-off-by: Feng Wu <feng.wu@xxxxxxxxx> > > --- > > arch/x86/kvm/vmx.c | 10 ++++++---- > > 1 file changed, 6 insertions(+), 4 deletions(-) > > > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > > index dcc4de3..1d37e50 100644 > > --- a/arch/x86/kvm/vmx.c > > +++ b/arch/x86/kvm/vmx.c > > @@ -3421,13 +3421,15 @@ static int vmx_set_cr4(struct kvm_vcpu *vcpu, > unsigned long cr4) > > hw_cr4 &= ~X86_CR4_PAE; > > hw_cr4 |= X86_CR4_PSE; > > /* > > - * SMEP is disabled if CPU is in non-paging mode in > > - * hardware. However KVM always uses paging mode to > > + * SMEP/SMAP is disabled if CPU is in non-paging mode > > + * in hardware. However KVM always uses paging mode to > > * emulate guest non-paging mode with TDP. > > - * To emulate this behavior, SMEP needs to be manually > > - * disabled when guest switches to non-paging mode. > > + * To emulate this behavior, SMEP/SMAP needs to be > > + * manually disabled when guest switches to non-paging > > + * mode. > > */ > > hw_cr4 &= ~X86_CR4_SMEP; > > + hw_cr4 &= ~X86_CR4_SMAP; > > Why not > > hw_cr4 &= ~(X86_CR4_SMEP | X86_CR4_SMAP); > > ? Sure, your suggestion is cleaner, I will change it in the next version, thanks for the comments! > > Jan > > > } else if (!(cr4 & X86_CR4_PAE)) { > > hw_cr4 &= ~X86_CR4_PAE; > > } > > > Thanks, Feng -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
