[Xen-devel] [PATCH 2/3] x86/xsaves: fix overwriting between non-lazy/lazy xsave[sc]

[Shuai Ruan <shuai.ruan@xxxxxxxxxxxxxxx>]

The offset at which components xsaved by xsave[sc] are not fixed.
So when when a save with v->fpu_dirtied set is followed by one
with v->fpu_dirtied clear, non-lazy xsave[sc] may overwriting data
written by the lazy one.

When xsave[sc] is enable, vcpu_xsave_mask will return XSTATE_ALL when
v->fpu_dirtied clear and v->arch.nonlazy_xstate_used is set.

Signed-off-by: Shuai Ruan <shuai.ruan@xxxxxxxxxxxxxxx>
---
 xen/arch/x86/i387.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xen/arch/x86/i387.c b/xen/arch/x86/i387.c
index 67016c9..e3a7bc0 100644
--- a/xen/arch/x86/i387.c
+++ b/xen/arch/x86/i387.c
@@ -118,7 +118,7 @@ static inline uint64_t vcpu_xsave_mask(const struct vcpu *v)
     if ( v->fpu_dirtied )
         return v->arch.nonlazy_xstate_used ? XSTATE_ALL : XSTATE_LAZY;
 
-    return v->arch.nonlazy_xstate_used ? XSTATE_NONLAZY : 0;
+    return ( cpu_has_xsaves || cpu_has_xsavec ) ? XSTATE_ALL : XSTATE_NONLAZY;
 }
 
 /* Save x87 extended state */
-- 
1.9.1


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel