diff mbox

[v2] VMX: fix realmode emulation SReg handling

Message ID 58139723020000780011AA89@prv-mh.provo.novell.com (mailing list archive)
State New, archived
Headers show

Commit Message

Jan Beulich Oct. 28, 2016, 4:21 p.m. UTC 
Commit 0888d36bb2 ("x86/emul: Correct the decoding of SReg3 operands")
overlooked three places where x86_seg_cs was assumed to be zero.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Release-acked-by: Wei Liu <wei.liu2@citrix.com>
---
v2: Add BUILD_BUG_ON() and use ARRAY_SIZE(reg) as loop bound.
VMX: fix realmode emulation SReg handling

Commit 0888d36bb2 ("x86/emul: Correct the decoding of SReg3 operands")
overlooked three places where x86_seg_cs was assumed to be zero.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Release-acked-by: Wei Liu <wei.liu2@citrix.com>
---
v2: Add BUILD_BUG_ON() and use ARRAY_SIZE(reg) as loop bound.

--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -1496,21 +1496,23 @@ static void vmx_update_guest_cr(struct v
             enum x86_segment s; 
             struct segment_register reg[x86_seg_tr + 1];
 
+            BUILD_BUG_ON(x86_seg_tr != x86_seg_gs + 1);
+
             /* Entering or leaving real mode: adjust the segment registers.
              * Need to read them all either way, as realmode reads can update
              * the saved values we'll use when returning to prot mode. */
-            for ( s = x86_seg_cs ; s <= x86_seg_tr ; s++ )
+            for ( s = 0; s < ARRAY_SIZE(reg); s++ )
                 vmx_get_segment_register(v, s, &reg[s]);
             v->arch.hvm_vmx.vmx_realmode = realmode;
             
             if ( realmode )
             {
-                for ( s = x86_seg_cs ; s <= x86_seg_tr ; s++ )
+                for ( s = 0; s < ARRAY_SIZE(reg); s++ )
                     vmx_set_segment_register(v, s, &reg[s]);
             }
             else 
             {
-                for ( s = x86_seg_cs ; s <= x86_seg_tr ; s++ ) 
+                for ( s = 0; s < ARRAY_SIZE(reg); s++ )
                     if ( !(v->arch.hvm_vmx.vm86_segment_mask & (1<<s)) )
                         vmx_set_segment_register(
                             v, s, &v->arch.hvm_vmx.vm86_saved_seg[s]);

Comments

Tian, Kevin Nov. 4, 2016, 6:50 a.m. UTC | #1 
> From: Jan Beulich [mailto:JBeulich@suse.com]
> Sent: Saturday, October 29, 2016 12:21 AM
> 
> Commit 0888d36bb2 ("x86/emul: Correct the decoding of SReg3 operands")
> overlooked three places where x86_seg_cs was assumed to be zero.
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
> Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
> Release-acked-by: Wei Liu <wei.liu2@citrix.com>
> ---
> v2: Add BUILD_BUG_ON() and use ARRAY_SIZE(reg) as loop bound.

Acked-by: Kevin Tian <kevin.tian@intel.com>
diff mbox

Patch

--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -1496,21 +1496,23 @@  static void vmx_update_guest_cr(struct v
             enum x86_segment s; 
             struct segment_register reg[x86_seg_tr + 1];
 
+            BUILD_BUG_ON(x86_seg_tr != x86_seg_gs + 1);
+
             /* Entering or leaving real mode: adjust the segment registers.
              * Need to read them all either way, as realmode reads can update
              * the saved values we'll use when returning to prot mode. */
-            for ( s = x86_seg_cs ; s <= x86_seg_tr ; s++ )
+            for ( s = 0; s < ARRAY_SIZE(reg); s++ )
                 vmx_get_segment_register(v, s, &reg[s]);
             v->arch.hvm_vmx.vmx_realmode = realmode;
             
             if ( realmode )
             {
-                for ( s = x86_seg_cs ; s <= x86_seg_tr ; s++ )
+                for ( s = 0; s < ARRAY_SIZE(reg); s++ )
                     vmx_set_segment_register(v, s, &reg[s]);
             }
             else 
             {
-                for ( s = x86_seg_cs ; s <= x86_seg_tr ; s++ ) 
+                for ( s = 0; s < ARRAY_SIZE(reg); s++ )
                     if ( !(v->arch.hvm_vmx.vm86_segment_mask & (1<<s)) )
                         vmx_set_segment_register(
                             v, s, &v->arch.hvm_vmx.vm86_saved_seg[s]);