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);
?
Jan
> } else if (!(cr4 & X86_CR4_PAE)) {
> hw_cr4 &= ~X86_CR4_PAE;
> }
>
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