Re: port-i386/52266: Double fault early in boot with AMD Am5x86 CPU

[Kimihiro Nonaka <nonakap%gmail.com@localhost>]

The following reply was made to PR port-i386/52266; it has been noted by GNATS.

From: Kimihiro Nonaka <nonakap%gmail.com@localhost>
To: "gnats-bugs%netbsd.org@localhost" <gnats-bugs%netbsd.org@localhost>
Cc: NONAKA Kimihiro <nonaka%netbsd.org@localhost>, "gnats-admin%netbsd.org@localhost" <gnats-admin%netbsd.org@localhost>, 
	"netbsd-bugs%netbsd.org@localhost" <netbsd-bugs%netbsd.org@localhost>, Andreas Gustafsson <gson%gson.org@localhost>
Subject: Re: port-i386/52266: Double fault early in boot with AMD Am5x86 CPU
Date: Tue, 11 Jul 2017 18:12:37 +0900

 Hi,
 
 2017-07-09 14:45 GMT+09:00 John D. Baker <jdbaker%mylinuxisp.com@localhost>:
 
 >  Just to double check, I grabbed:
 >
 >    http://nycdn.netbsd.org/pub/NetBSD-daily/HEAD/201707082110Z/i386/binary/kernel/netbsd-GENERIC.gz
 >
 >  and it panics on the net4501 the same as my locally-built kernels:
 
 Could you try the following patch?
 
 diff --git a/sys/arch/x86/x86/lapic.c b/sys/arch/x86/x86/lapic.c
 index 415bb65b4e5..f87de042054 100644
 --- a/sys/arch/x86/x86/lapic.c
 +++ b/sys/arch/x86/x86/lapic.c
 @@ -237,7 +237,8 @@ lapic_is_x2apic(void)
  {
      uint64_t msr;
 
 -    if (rdmsr_safe(MSR_APICBASE, &msr) == EFAULT)
 +    if (!ISSET(cpu_feature[0], CPUID_MSR) ||
 +        rdmsr_safe(MSR_APICBASE, &msr) == EFAULT)
          return false;
      return (msr & (APICBASE_EN | APICBASE_EXTD)) ==
          (APICBASE_EN | APICBASE_EXTD);
 
 Regards,
 -- 
 Kimihiro Nonaka