[Xen-changelog] [xen staging] x86emul: fix vector-length check for AVX512F scalar fused-multiply-add insns

[patchbot@xxxxxxx]

commit 1f2a4cb17b4b925dc279ab263907844ed5800f20
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue Dec 18 15:20:32 2018 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Dec 18 15:20:32 2018 +0100

    x86emul: fix vector-length check for AVX512F scalar fused-multiply-add insns
    
    The check needs to happen whenever EVEX.b (SDM nomenclature) is clear,
    not just in the memory operand case.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/arch/x86/x86_emulate/x86_emulate.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/xen/arch/x86/x86_emulate/x86_emulate.c 
b/xen/arch/x86/x86_emulate/x86_emulate.c
index d6c97651e2..a3d7e33385 100644
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -8532,11 +8532,9 @@ x86_emulate(
     case X86EMUL_OPC_EVEX_66(0x0f38, 0xbd): /* vfnmadd231s{s,d} 
xmm/mem,xmm,xmm{k} */
     case X86EMUL_OPC_EVEX_66(0x0f38, 0xbf): /* vfnmsub231s{s,d} 
xmm/mem,xmm,xmm{k} */
         host_and_vcpu_must_have(avx512f);
-        if ( ea.type == OP_MEM )
-        {
-            generate_exception_if(evex.br, EXC_UD);
+        generate_exception_if(ea.type != OP_REG && evex.br, EXC_UD);
+        if ( !evex.br )
             avx512_vlen_check(true);
-        }
         goto simd_zmm;
 
     case X86EMUL_OPC(0x0f38, 0xc8):     /* sha1nexte xmm/m128,xmm */
--
generated by git-patchbot for /home/xen/git/xen.git#staging

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