[PATCH v2 2/2] x86/hvm: Always do SMAP check when updating secondary system time for guest

[Feng Wu <feng.wu@intel.com>]

In this patch, we always do the SMAP check when updating secondary
system time for the guest when SMAP is enabled by it.

Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Signed-off-by: Feng Wu <feng.wu@intel.com>
---
 xen/arch/x86/time.c          | 9 ++++++++-
 xen/include/asm-x86/domain.h | 2 +-
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c
index a4e1656..797f0cf 100644
--- a/xen/arch/x86/time.c
+++ b/xen/arch/x86/time.c
@@ -821,7 +821,7 @@ static void __update_vcpu_system_time(struct vcpu *v, int force)
         v->arch.pv_vcpu.pending_system_time = _u;
 }
 
-bool_t update_secondary_system_time(const struct vcpu *v,
+bool_t update_secondary_system_time(struct vcpu *v,
                                     struct vcpu_time_info *u)
 {
     XEN_GUEST_HANDLE(vcpu_time_info_t) user_u = v->arch.time_info_guest;
@@ -829,9 +829,14 @@ bool_t update_secondary_system_time(const struct vcpu *v,
     if ( guest_handle_is_null(user_u) )
         return 1;
 
+    v->arch.smap_check_policy = SMAP_CHECK_ENABLED;
+
     /* 1. Update userspace version. */
     if ( __copy_field_to_guest(user_u, u, version) == sizeof(u->version) )
+    {
+        v->arch.smap_check_policy = SMAP_CHECK_HONOR_CPL_AC;
         return 0;
+    }
     wmb();
     /* 2. Update all other userspace fields. */
     __copy_to_guest(user_u, u, 1);
@@ -840,6 +845,8 @@ bool_t update_secondary_system_time(const struct vcpu *v,
     u->version = version_update_end(u->version);
     __copy_field_to_guest(user_u, u, version);
 
+    v->arch.smap_check_policy = SMAP_CHECK_HONOR_CPL_AC;
+
     return 1;
 }
 
diff --git a/xen/include/asm-x86/domain.h b/xen/include/asm-x86/domain.h
index d7cac4f..9440351 100644
--- a/xen/include/asm-x86/domain.h
+++ b/xen/include/asm-x86/domain.h
@@ -466,7 +466,7 @@ struct arch_vcpu
 #define hvm_svm         hvm_vcpu.u.svm
 
 bool_t update_runstate_area(struct vcpu *);
-bool_t update_secondary_system_time(const struct vcpu *,
+bool_t update_secondary_system_time(struct vcpu *,
                                     struct vcpu_time_info *);
 
 void vcpu_show_execution_state(struct vcpu *);
-- 
1.8.3.1