PR/60619 CVS commit: [netbsd-10] src

["Martin Husemann" <martin%netbsd.org@localhost>]

The following reply was made to PR port-amd64/60619; it has been noted by GNATS.

From: "Martin Husemann" <martin%netbsd.org@localhost>
To: gnats-bugs%gnats.NetBSD.org@localhost
Cc: 
Subject: PR/60619 CVS commit: [netbsd-10] src
Date: Thu, 27 Aug 2026 17:11:27 +0000

 Module Name:	src
 Committed By:	martin
 Date:		Thu Aug 27 17:11:27 UTC 2026
 
 Modified Files:
 	src/sys/arch/x86/x86 [netbsd-10]: identcpu.c
 	src/usr.sbin/cpuctl/arch [netbsd-10]: i386.c
 
 Log Message:
 Pull up following revision(s) (requested by andvar in ticket #1334):
 
 	sys/arch/x86/x86/identcpu.c: revision 1.142
 	usr.sbin/cpuctl/arch/i386.c: revision 1.149
 
 Decode L2 cache associativity for VIA CPUs using the AMD cache lookup table for
 the 0x80000006 CPUID function associativity value.
 
 Use `cpuid leaf 4' to get cache parameters for Zhaoxin and late VIA CPU models.
 
 VIA datasheets mention that associativity is stored as a decimal value. However,
 in practice, it is encoded the AMD way and does not store the actual value.
 
 Using the raw value leads to an incorrect CPU colors calculation, causing a
 panic on KX-7000 (since the result is not a power of two) and incorrect CPU
 colors values on other CPU models (e.g. as visible in `vmstat -s').
 
 Decoding value using the AMD cache lookup table produces correct values in all
 cases I have tested or verified using CPUID dumps available online.
 
 Additionally, Zhaoxin and late VIA CPUs (CNQ and newer) prefer the Intel
 `cpuid leaf 4' function to get cache parameters. Check whether cpuid_level
 is equal to or greater than 4 to identify these CPUs and override cache values
 (including L1) by calling cpu_dcp_cacheinfo(ci, 4). L3 cache information is
 available only through this method.
 
 Fixes PR kern/60619
 
 Similar changes will be committed separately to the cpuctl utility.
 Thanks to skrll@ for comments on the patch.
 
 cpuctl(8): decode L2 cache associativity for VIA CPUs using the AMD cache lookup
 table for the 0x80000006 CPUID function associativity value.
 
 Use `cpuid leaf 4' to get cache parameters for Zhaoxin and late VIA CPU models.
 
 Mirrors the changes from identcpu.c rev. 1.142.
 
 Additionally, use via_cpu_probe() and via_cpu_cacheinfo() for CPUVENDOR_IDT
 family > 6 CPUs to identify Zhaoxin CPUs and their features.
 Also, print feature 5-7 bits for CPUVENDOR_IDT, which appear to be compatible
 with Intel.
 
 Use vendorname = "Zhaoxin" for family 7 models.
 
 Tested on various 32-bit and 64-bit VIA and Zhaoxin CPUs
 (Samuel 2 / Nehemiah, Esther (32-bit), multiple Nano models, and KX-U6580/7000).
 
 PR kern/60619
 
 
 To generate a diff of this commit:
 cvs rdiff -u -r1.123.4.4 -r1.123.4.5 src/sys/arch/x86/x86/identcpu.c
 cvs rdiff -u -r1.133.2.4 -r1.133.2.5 src/usr.sbin/cpuctl/arch/i386.c
 
 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.