patch 'eal/x86: fix LZCNT CPU flag' has been queued to stable release 24.11.9

[luca.boccassi at gmail.com]

Hi,

FYI, your patch has been queued to stable release 24.11.9

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 10/29/26. So please
shout if anyone has objections.

Also note that after the patch there's a diff of the upstream commit vs the
patch applied to the branch. This will indicate if there was any rebasing
needed to apply to the stable branch. If there were code changes for rebasing
(ie: not only metadata diffs), please double check that the rebase was
correctly done.

Queued patches are on a temporary branch at:
https://github.com/bluca/dpdk-stable

This queued commit can be viewed at:
https://github.com/bluca/dpdk-stable/commit/387eb1d09e33cea43b829e33a9078b877528ce69

Thanks.

Luca Boccassi

---
>From 387eb1d09e33cea43b829e33a9078b877528ce69 Mon Sep 17 00:00:00 2001
From: Yonghao Li <cruselee1 at live.cn>
Date: Fri, 28 Aug 2026 21:32:52 +0100
Subject: [PATCH] eal/x86: fix LZCNT CPU flag

[ upstream commit a0fad8854dc36c8e0734bc7bb1eab87a8caa91e2 ]

LZCNT support is enumerated by CPUID.80000001H:ECX[5]. The current
definition checks ECX bit 4, which identifies CR8 legacy mode on AMD
processors and is reserved on Intel processors. As a result,
RTE_CPUFLAG_LZCNT can be reported incorrectly.

Check ECX bit 5 instead.

Fixes: af75078fece3 ("first public release")

Signed-off-by: Yonghao Li <cruselee1 at live.cn>
Acked-by: David Marchand <david.marchand at redhat.com>
Acked-by: Bruce Richardson <bruce.richardson at intel.com>
---
 .mailmap                   | 12 +++++++-----
 lib/eal/x86/rte_cpuflags.c |  2 +-
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/.mailmap b/.mailmap
index 77fc075dcb2..fb2d4cab797 100644
--- a/.mailmap
+++ b/.mailmap
@@ -1845,15 +1845,17 @@ Yochai Hagvi <yochai.hagvi at intel.com>
 Yogesh Bhosale <yogesh.bhosale at intel.com>
 Yogesh Jangra <yogesh.jangra at intel.com>
 Yogev Chaimovich <yogev at cgstowernetworks.com>
-Yongjie Gu <yongjiex.gu at intel.com>
-Yongji Xie <xieyongji at baidu.com>
 Yong Liu <yong.liu at intel.com>
-Yongping Zhang <yongping.zhang at broadcom.com>
-Yongseok Koh <yskoh at mellanox.com>
 Yong Wang <wang.yong19 at zte.com.cn> <yongwang at vmware.com>
-Yongxin Liu <yongxin.liu at windriver.com>
 Yong Xu <yong.xu at corigine.com>
 Yong Zhang <zhang.yong25 at zte.com.cn>
+Yongfeng Wang <mannywang at tencent.com>
+Yonghao Li <cruselee1 at live.cn>
+Yongji Xie <xieyongji at baidu.com>
+Yongjie Gu <yongjiex.gu at intel.com>
+Yongping Zhang <yongping.zhang at broadcom.com>
+Yongseok Koh <yskoh at mellanox.com>
+Yongxin Liu <yongxin.liu at windriver.com>
 Yoni Gilad <yonig at radcom.com>
 Yosef Raisman <yraisman at amazon.com>
 Youri Querry <youri.querry_1 at nxp.com>
diff --git a/lib/eal/x86/rte_cpuflags.c b/lib/eal/x86/rte_cpuflags.c
index 90389c66fc0..7fdb8ac6551 100644
--- a/lib/eal/x86/rte_cpuflags.c
+++ b/lib/eal/x86/rte_cpuflags.c
@@ -136,7 +136,7 @@ struct feature_entry rte_cpu_feature_table[] = {
 	FEAT_DEF(AVX512VP2INTERSECT, 0x00000007, 0, RTE_REG_EDX,  8)
 
 	FEAT_DEF(LAHF_SAHF, 0x80000001, 0, RTE_REG_ECX,  0)
-	FEAT_DEF(LZCNT, 0x80000001, 0, RTE_REG_ECX,  4)
+	FEAT_DEF(LZCNT, 0x80000001, 0, RTE_REG_ECX,  5)
 	FEAT_DEF(MONITORX, 0x80000001, 0, RTE_REG_ECX,  29)
 
 	FEAT_DEF(SYSCALL, 0x80000001, 0, RTE_REG_EDX, 11)
-- 
2.47.3

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2026-10-27 11:43:57.965155754 +0000
+++ 0109-eal-x86-fix-LZCNT-CPU-flag.patch	2026-10-27 11:43:53.642063410 +0000
@@ -1 +1 @@
-From a0fad8854dc36c8e0734bc7bb1eab87a8caa91e2 Mon Sep 17 00:00:00 2001
+From 387eb1d09e33cea43b829e33a9078b877528ce69 Mon Sep 17 00:00:00 2001
@@ -5,0 +6,2 @@
+[ upstream commit a0fad8854dc36c8e0734bc7bb1eab87a8caa91e2 ]
+
@@ -14 +15,0 @@
-Cc: stable at dpdk.org
@@ -20,3 +21,3 @@
- .mailmap                   | 1 +
- lib/eal/x86/rte_cpuflags.c | 2 +-
- 2 files changed, 2 insertions(+), 1 deletion(-)
+ .mailmap                   | 12 +++++++-----
+ lib/eal/x86/rte_cpuflags.c |  2 +-
+ 2 files changed, 8 insertions(+), 6 deletions(-)
@@ -25 +26 @@
-index b04bc3c1d9..57f7a9f87a 100644
+index 77fc075dcb2..fb2d4cab797 100644
@@ -28 +29,11 @@
-@@ -1948,6 +1948,7 @@ Yong Wang <wang.yong19 at zte.com.cn> <yongwang at vmware.com>
+@@ -1845,15 +1845,17 @@ Yochai Hagvi <yochai.hagvi at intel.com>
+ Yogesh Bhosale <yogesh.bhosale at intel.com>
+ Yogesh Jangra <yogesh.jangra at intel.com>
+ Yogev Chaimovich <yogev at cgstowernetworks.com>
+-Yongjie Gu <yongjiex.gu at intel.com>
+-Yongji Xie <xieyongji at baidu.com>
+ Yong Liu <yong.liu at intel.com>
+-Yongping Zhang <yongping.zhang at broadcom.com>
+-Yongseok Koh <yskoh at mellanox.com>
+ Yong Wang <wang.yong19 at zte.com.cn> <yongwang at vmware.com>
+-Yongxin Liu <yongxin.liu at windriver.com>
@@ -31 +42 @@
- Yongfeng Wang <mannywang at tencent.com>
++Yongfeng Wang <mannywang at tencent.com>
@@ -33,3 +44,8 @@
- Yongji Xie <xieyongji at baidu.com>
- Yongjie Gu <yongjiex.gu at intel.com>
- Yongping Zhang <yongping.zhang at broadcom.com>
++Yongji Xie <xieyongji at baidu.com>
++Yongjie Gu <yongjiex.gu at intel.com>
++Yongping Zhang <yongping.zhang at broadcom.com>
++Yongseok Koh <yskoh at mellanox.com>
++Yongxin Liu <yongxin.liu at windriver.com>
+ Yoni Gilad <yonig at radcom.com>
+ Yosef Raisman <yraisman at amazon.com>
+ Youri Querry <youri.querry_1 at nxp.com>
@@ -37 +53 @@
-index 5d1f352e04..80b71a3ce0 100644
+index 90389c66fc0..7fdb8ac6551 100644
@@ -40 +56 @@
-@@ -137,7 +137,7 @@ struct feature_entry rte_cpu_feature_table[] = {
+@@ -136,7 +136,7 @@ struct feature_entry rte_cpu_feature_table[] = {