[xen staging] x86emul: correct test harness {evex} assembler capability check

[patchbot@xxxxxxx]

commit ba7b169c9f0922886001dc0b27dc4c28dfe15631
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Fri May 22 14:35:04 2020 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Fri May 22 14:35:04 2020 +0200

    x86emul: correct test harness {evex} assembler capability check
    
    The {evex} pseudo prefix gets rejected by gas for insns not allowing
    EVEX encoding. Except there's a gas bug due to which its check gets
    bypassed for insns without operands. Let's not rely on that bug to
    remain there.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 tools/tests/x86_emulator/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/tests/x86_emulator/Makefile 
b/tools/tests/x86_emulator/Makefile
index 7ce882cb78..b414773810 100644
--- a/tools/tests/x86_emulator/Makefile
+++ b/tools/tests/x86_emulator/Makefile
@@ -112,7 +112,7 @@ $(foreach flavor,$(SIMD) $(FMA),$(eval $(call 
simd-check-cc,$(flavor))))
 
 # Also explicitly check for {evex} pseudo-prefix support, which got introduced
 # only after AVX512F and some of its extensions.
-TARGET-$(shell echo 'asm("{evex} vzeroall");' | $(CC) -x c -c -o /dev/null - 
|| echo y) :=
+TARGET-$(shell echo 'asm("{evex} vmovaps %xmm0$(comma)%xmm0");' | $(CC) -x c 
-c -o /dev/null - || echo y) :=
 
 ifeq ($(TARGET-y),)
 $(warning Test harness not built, use newer compiler than "$(CC)" (version 
$(shell $(CC) -dumpversion)) and an "{evex}" capable assembler)
--
generated by git-patchbot for /home/xen/git/xen.git#staging