[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v2 4/7] VMX: Disable SMAP feature when guest is in non-paging mode
SMAP is disabled if CPU is in non-paging mode in hardware. However Xen always uses paging mode to emulate guest non-paging mode with HAP. To emulate this behavior, SMAP needs to be manually disabled when guest switches to non-paging mode. This logic is similiar with SMEP. Signed-off-by: Feng Wu <feng.wu@xxxxxxxxx> --- xen/arch/x86/hvm/vmx/vmx.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c index 94f3db2..79dd272 100644 --- a/xen/arch/x86/hvm/vmx/vmx.c +++ b/xen/arch/x86/hvm/vmx/vmx.c @@ -1310,12 +1310,12 @@ static void vmx_update_guest_cr(struct vcpu *v, unsigned int cr) if ( !hvm_paging_enabled(v) ) { /* - * SMEP is disabled if CPU is in non-paging mode in hardware. + * SMEP/SMAP is disabled if CPU is in non-paging mode in hardware. * However Xen always uses paging mode to emulate guest non-paging - * mode. To emulate this behavior, SMEP needs to be manually + * mode. To emulate this behavior, SMEP/SMAP needs to be manually * disabled when guest VCPU is in non-paging mode. */ - v->arch.hvm_vcpu.hw_cr[4] &= ~X86_CR4_SMEP; + v->arch.hvm_vcpu.hw_cr[4] &= ~(X86_CR4_SMEP | X86_CR4_SMAP); } __vmwrite(GUEST_CR4, v->arch.hvm_vcpu.hw_cr[4]); break; -- 1.8.3.1 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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