From mboxrd@z Thu Jan 1 00:00:00 1970 From: Feng Wu Subject: [PATCH v2 4/7] VMX: Disable SMAP feature when guest is in non-paging mode Date: Wed, 23 Apr 2014 22:36:54 +0800 Message-ID: <1398263814-32141-1-git-send-email-feng.wu@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: xen-devel@lists.xen.org Cc: kevin.tian@intel.com, Feng Wu , JBeulich@suse.com, andrew.cooper3@citrix.com, eddie.dong@intel.com, jun.nakajima@intel.com, ian.campbell@citrix.com List-Id: xen-devel@lists.xenproject.org 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 --- 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