[Xen-changelog] [xen stable-4.6] x86emul: suppress writeback upon unsuccessful MMX/SSE/AVX insn emulation

[patchbot@xxxxxxx]

commit 9362eb13ab564ade8f0aea29ab3109d53de6da01
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Fri May 27 14:36:18 2016 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Fri May 27 14:36:18 2016 +0200

    x86emul: suppress writeback upon unsuccessful MMX/SSE/AVX insn emulation
    
    This in particular prevents updating guest IP when handling the retry
    needed to forward the memory access to qemu.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    master commit: 2bb230972c5ddb1ca823f47750b5d46a9d302d0e
    master date: 2016-05-19 12:06:33 +0200
---
 xen/arch/x86/x86_emulate/x86_emulate.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/xen/arch/x86/x86_emulate/x86_emulate.c 
b/xen/arch/x86/x86_emulate/x86_emulate.c
index 9558bae..8f3ffc2 100644
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -4142,6 +4142,8 @@ x86_emulate(
         if ( !rc && (b & 1) && (ea.type == OP_MEM) )
             rc = ops->write(ea.mem.seg, ea.mem.off, mmvalp,
                             ea.bytes, ctxt);
+        if ( rc )
+            goto done;
         dst.type = OP_NONE;
         break;
     }
@@ -4396,6 +4398,8 @@ x86_emulate(
         if ( !rc && (b != 0x6f) && (ea.type == OP_MEM) )
             rc = ops->write(ea.mem.seg, ea.mem.off, mmvalp,
                             ea.bytes, ctxt);
+        if ( rc )
+            goto done;
         dst.type = OP_NONE;
         break;
     }
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.6

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