Re: [PATCH 5/6] host/i386: assume presence of SSSE3

[Zhao Liu]

On Fri, May 31, 2024 at 11:14:56AM +0200, Paolo Bonzini wrote:
> Date: Fri, 31 May 2024 11:14:56 +0200
> From: Paolo Bonzini 
> Subject: [PATCH 5/6] host/i386: assume presence of SSSE3
> X-Mailer: git-send-email 2.45.1
> 
> QEMU now requires an x86-64-v2 host, which has SSSE3 instructions
> (notably, PSHUFB which is used by QEMU's AES implementation).
> Do not bother checking it.
> 
> Signed-off-by: Paolo Bonzini 
> ---
>  util/cpuinfo-i386.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

Reviewed-by: Zhao Liu 

[PATCH 5/6] host/i386: assume presence of SSSE3

[Paolo Bonzini]

QEMU now requires an x86-64-v2 host, which has SSSE3 instructions
(notably, PSHUFB which is used by QEMU's AES implementation).
Do not bother checking it.

Signed-off-by: Paolo Bonzini 
---
 util/cpuinfo-i386.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/util/cpuinfo-i386.c b/util/cpuinfo-i386.c
index ca74ef04f54..b413075b9f2 100644
--- a/util/cpuinfo-i386.c
+++ b/util/cpuinfo-i386.c
@@ -38,8 +38,8 @@ unsigned __attribute__((constructor)) cpuinfo_init(void)
 info |= (c & bit_POPCNT ? CPUINFO_POPCNT : 0);
 info |= (c & bit_PCLMUL ? CPUINFO_PCLMUL : 0);
 
-/* Our AES support requires PSHUFB as well. */
-info |= ((c & bit_AES) && (c & bit_SSSE3) ? CPUINFO_AES : 0);
+/* NOTE: our AES support requires SSSE3 (PSHUFB) as well. */
+info |= (c & bit_AES) ? CPUINFO_AES : 0;
 
 /* For AVX features, we must check available and usable. */
 if ((c & bit_AVX) && (c & bit_OSXSAVE)) {
-- 
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