[Xen-changelog] [xen-unstable] [HVM][VMX] Save GS_SHADOW MSR only on x86/64.

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User kfraser@xxxxxxxxxxxxxxxxxxxxx
# Date 1166700159 0
# Node ID fd1ccd818f2c7da431e1e1ce9cc6ea3392f380c1
# Parent  8af3df2f4b01a047c69805886cf28fa43ffeac56
[HVM][VMX] Save GS_SHADOW MSR only on x86/64.
Bug found by Kouya Shimura <kouya@xxxxxxxxxxxxxx>
Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx>
---
 xen/arch/x86/hvm/vmx/vmx.c |   12 ++++++++----
 1 files changed, 8 insertions(+), 4 deletions(-)

diff -r 8af3df2f4b01 -r fd1ccd818f2c xen/arch/x86/hvm/vmx/vmx.c
--- a/xen/arch/x86/hvm/vmx/vmx.c        Thu Dec 21 11:10:43 2006 +0000
+++ b/xen/arch/x86/hvm/vmx/vmx.c        Thu Dec 21 11:22:39 2006 +0000
@@ -277,6 +277,12 @@ static void vmx_restore_host_msrs(void)
     }
 }
 
+static void vmx_save_guest_msrs(struct vcpu *v)
+{
+    /* MSR_SHADOW_GS_BASE may have been changed by swapgs instruction. */
+    rdmsrl(MSR_SHADOW_GS_BASE, v->arch.hvm_vmx.msr_state.shadow_gs);
+}
+
 static void vmx_restore_guest_msrs(struct vcpu *v)
 {
     struct vmx_msr_state *guest_msr_state, *host_msr_state;
@@ -308,6 +314,7 @@ static void vmx_restore_guest_msrs(struc
 
 #define vmx_save_host_msrs()        ((void)0)
 #define vmx_restore_host_msrs()     ((void)0)
+#define vmx_save_guest_msrs(v)      ((void)0)
 #define vmx_restore_guest_msrs(v)   ((void)0)
 
 static inline int long_mode_do_msr_read(struct cpu_user_regs *regs)
@@ -373,10 +380,7 @@ static inline void vmx_restore_dr(struct
 
 static void vmx_ctxt_switch_from(struct vcpu *v)
 {
-    /* NB. MSR_SHADOW_GS_BASE may be changed by swapgs instrucion in guest,
-     * so we must save it. */
-    rdmsrl(MSR_SHADOW_GS_BASE, v->arch.hvm_vmx.msr_state.shadow_gs);
-
+    vmx_save_guest_msrs(v);
     vmx_restore_host_msrs();
     vmx_save_dr(v);
 }

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