KVM, pkeys: disable pkeys for guests in non-paging mode

Pkeys 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, pkeys needs to be manually disabled when guest
switches to non-paging mode.

Signed-off-by: Huaitong Han <huaitong.han@intel.com>
Reviewed-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 161230016dfaa58c1206d60d5523dd50a263d0af..1b8a41f64d357beeef5e63c15307774a172a935d 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3893,13 +3893,17 @@ static int vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
 
        if (!enable_unrestricted_guest && !is_paging(vcpu))
                /*
-                * SMEP/SMAP is disabled if CPU is in non-paging mode in
-                * hardware.  However KVM always uses paging mode without
-                * unrestricted guest.
-                * To emulate this behavior, SMEP/SMAP needs to be manually
-                * disabled when guest switches to non-paging mode.
+                * SMEP/SMAP/PKU is disabled if CPU is in non-paging mode in
+                * hardware.  To emulate this behavior, SMEP/SMAP/PKU needs
+                * to be manually disabled when guest switches to non-paging
+                * mode.
+                *
+                * If !enable_unrestricted_guest, the CPU is always running
+                * with CR0.PG=1 and CR4 needs to be modified.
+                * If enable_unrestricted_guest, the CPU automatically
+                * disables SMEP/SMAP/PKU when the guest sets CR0.PG=0.
                 */
-               hw_cr4 &= ~(X86_CR4_SMEP | X86_CR4_SMAP);
+               hw_cr4 &= ~(X86_CR4_SMEP | X86_CR4_SMAP | X86_CR4_PKE);
 
        vmcs_writel(CR4_READ_SHADOW, cr4);
        vmcs_writel(GUEST_CR4, hw_cr4);