x86/hvm: disable pkeys for guests in non-paging mode

This patch disables pkeys for guest in non-paging mode, However XEN always uses
paging mode to emulate guest non-paging mode, To emulate this behavior, pkeys
needs to be manually disabled when guest switches to non-paging mode.

Signed-off-by: Huaitong Han <huaitong.han@intel.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Kevin Tian <kevin.tian@intel.com>

diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 195def661e999ab4de2f7e342878ce8a2d8c4e09..b9f340c35f8c72d69d89f8f54c2cbc91c482d09a 100644 (file)
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -1379,12 +1379,13 @@ static void vmx_update_guest_cr(struct vcpu *v, unsigned int cr)
         if ( !hvm_paging_enabled(v) )
         {
             /*
-             * 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/SMAP needs to be manually
-             * disabled when guest VCPU is in non-paging mode.
+             * SMEP/SMAP/PKU 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/SMAP/PKU needs
+             * to be manually disabled when guest VCPU is in non-paging mode.
              */
-            v->arch.hvm_vcpu.hw_cr[4] &= ~(X86_CR4_SMEP | X86_CR4_SMAP);
+            v->arch.hvm_vcpu.hw_cr[4] &=
+                ~(X86_CR4_SMEP | X86_CR4_SMAP | X86_CR4_PKE);
         }
         __vmwrite(GUEST_CR4, v->arch.hvm_vcpu.hw_cr[4]);
         break;