[V7,1/5] x86/hvm: pkeys, disable pkeys for guests in non-paging mode
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Message ID 1453883430-9098-2-git-send-email-huaitong.han@intel.com
State New, archived
Headers show

Commit Message

Huaitong Han Jan. 27, 2016, 8:30 a.m. UTC
Changes in v7:
no changes.
----

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>
---
 xen/arch/x86/hvm/vmx/vmx.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

Comments

Jan Beulich Jan. 29, 2016, 4:27 p.m. UTC | #1
>>> On 27.01.16 at 09:30, <huaitong.han@intel.com> wrote:
> Changes in v7:
> no changes.
> ----
> 
> 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>
> ---

The "Changes in" belongs here, the way it's done now will require
extra work while committing. Hence this needs to be resent in
proper shape.

Jan

Patch
diff mbox

diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 04dde83..a0d51cb 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -1368,12 +1368,13 @@  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;