KVM: Disable SMAP for guests in EPT realmode and EPT unpaging mode

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>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 1320e0f8e61174d9a5c1da8d17e455f4a839cb1a..1f68c5831924d15dd741032cde2fafc46aae50ab 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3484,13 +3484,14 @@ 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_SMEP | X86_CR4_SMAP);
                } else if (!(cr4 & X86_CR4_PAE)) {
                        hw_cr4 &= ~X86_CR4_PAE;
                }