| Message ID | 1395923135-15329-5-git-send-email-feng.wu@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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@intel.com> > --- > 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); ? Jan > } else if (!(cr4 & X86_CR4_PAE)) { > hw_cr4 &= ~X86_CR4_PAE; > } >
> -----Original Message----- > From: kvm-owner@vger.kernel.org [mailto:kvm-owner@vger.kernel.org] On > Behalf Of Jan Kiszka > Sent: Friday, March 28, 2014 12:15 AM > To: Wu, Feng; pbonzini@redhat.com; gleb@redhat.com; hpa@zytor.com; > kvm@vger.kernel.org > 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@intel.com> > > --- > > 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@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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; } else if (!(cr4 & X86_CR4_PAE)) { hw_cr4 &= ~X86_CR4_PAE; }
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@intel.com> --- arch/x86/kvm/vmx.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)