Re: kern/50332 (AVX instructions don't work but OSXSAVE flag is set)

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

The following reply was made to PR port-xen/50332; it has been noted by GNATS.

From: Manuel Bouyer <bouyer%antioche.eu.org@localhost>
To: =?iso-8859-1?Q?Jarom=EDr?= Dole?ek <jaromir.dolecek%gmail.com@localhost>
Cc: "gnats-bugs%NetBSD.org@localhost" <gnats-bugs%netbsd.org@localhost>
Subject: Re: kern/50332 (AVX instructions don't work but OSXSAVE flag is set)
Date: Tue, 19 Jun 2018 10:20:14 +0200

 On Tue, Jun 19, 2018 at 12:55:27AM +0200, Jaromír Dole?ek wrote:
 > I'm working on this, have some local hacks in xen/cpu.c with which the
 > AVX test program passes. It seems we could just test for OSXSAVE being
 > already set in Xen case. For Xen, NetBSD kernel does not modify this
 > option. On my machine, that flag is set when I boot DOMU with default
 > options, and not set when I add no-xsave. So perhaps we could have
 > conditional on this only.
 > 
 > Manuel, you observed that panic after max's commits in 2017-11-07
 > which led to fixes in rev 1.26 and 1.27 of arch/x86/x86/fpu.c
 > 
 > I've checked on releng.netbsd.org, that machine has this flag also
 > off, but it's DOMU. Can you please confirm to me whether cpuctl
 > identify returns OSXSAVE on the appropriate DOM0, under which you run
 > that DOMU anita run which panicced?
 
 Here's what cpuctl says for dom0:
 xen1:/usr/home/bouyer#cpuctl identify 0
 cpu0: highest basic info 00000006
 cpu0: highest extended info 80000008
 cpu0: "Intel(R) Xeon(TM) CPU 3.00GHz"
 cpu0: Intel (686-class)
 cpu0: family 0xf model 0x6 stepping 0x4 (id 0xf64)
 cpu0: features 0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE>
 cpu0: features 0xbfebfbff<MCA,CMOV,PAT,PSE36,CFLUSH,DS,ACPI,MMX,FXSR,SSE,SSE2>
 cpu0: features 0xbfebfbff<SS,HTT,TM,SBF>
 cpu0: features1 0xe4bd<SSE3,DTES64,MONITOR,DS-CPL,VMX,EST,CID,CX16,xTPR,PDCM>
 cpu0: features2 0x20100800<SYSCALL/SYSRET,XD,EM64T>
 cpu0: features3 0x1<LAHF>
 cpu0: I-cache 12K uOp cache 8-way, D-cache 16KB 64B/line 8-way
 cpu0: L2 cache 2MB 64B/line 8-way
 cpu0: ITLB 4K/4M: 64 entries
 cpu0: DTLB 4K/4M: 64 entries
 cpu0: Initial APIC ID 5
 cpu0: Cluster/Package ID 1
 cpu0: Core ID 0
 cpu0: SMT ID 1
 cpu0: microcode version 0x2, platform ID 0
 
 The CPU is quite old. Also the hypervisor version changed ...
 
 -- 
 Manuel Bouyer <bouyer%antioche.eu.org@localhost>
      NetBSD: 26 ans d'experience feront toujours la difference
 --