amd64/170388: 8-STABLE amd64 past r233799 is unable to boot in certain KVM environments

Konstantin Belousov kostikbel at gmail.com
Sun Aug 5 14:00:06 UTC 2012


The following reply was made to PR amd64/170388; it has been noted by GNATS.

From: Konstantin Belousov <kostikbel at gmail.com>
To: Jimmy Olgeni <olgeni at freebsd.org>
Cc: FreeBSD-gnats-submit at freebsd.org, jkim at freebsd.org
Subject: Re: amd64/170388: 8-STABLE amd64 past r233799 is unable to boot in certain KVM environments
Date: Sun, 5 Aug 2012 16:55:18 +0300

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 On Sun, Aug 05, 2012 at 11:31:11AM +0200, Jimmy Olgeni wrote:
 >=20
 > >Number:         170388
 > >Category:       amd64
 > >Synopsis:       8-STABLE amd64 past r233799 is unable to boot in certain=
  KVM environments
 > >Confidential:   no
 > >Severity:       critical
 > >Priority:       high
 > >Responsible:    freebsd-amd64
 > >State:          open
 > >Quarter:       =20
 > >Keywords:      =20
 > >Date-Required:
 > >Class:          sw-bug
 > >Submitter-Id:   current-users
 > >Arrival-Date:   Sun Aug 05 09:40:02 UTC 2012
 > >Closed-Date:
 > >Last-Modified:
 > >Originator:     Jimmy Olgeni
 > >Release:        FreeBSD 8.3-STABLE amd64
 > >Organization:
 > >Environment:
 > >Description:
 >=20
 > FreeBSD 8-STABLE is unable to boot in some KVM environments after r233799.
 >=20
 > ------------------------------------------------------------------------
 > r233799 | jkim | 2012-04-02 20:27:06 +0200 (Mon, 02 Apr 2012) | 4 lines
 >=20
 > MFC:    r233702
 >=20
 > Work around Erratum 721 for AMD Family 10h and 12h processors.
 >=20
 > ------------------------------------------------------------------------
 >=20
 > The following panic message is shown immediately after the kernel starts:
 >=20
 > =3D=3D=3D
 > kernel trap 9 with interrupts disabled
 >=20
 > Fatal trap 9: general protection fault while in kernel mode
 > cpuid =3D 0; apic id =3D 00
 > instruction pointer    =3D 0x20:0xffffffff808fd8dc
 > stack pointer          =3D 0x28:0xffffffff80cd5440
 > frame pointer          =3D 0x28:0xffffffff80cd5470
 > code segment           =3D base 0x0,  limit 0xfffff, type 0x1b
 >                        =3D DPL 0, pres 1,  long 1, def32 0, gran 1
 > processor eflags       =3D resume,  IOPL =3D 0
 > current process        =3D 0 ()
 > trap number            =3D 9
 > panic: general protection fault
 > cpuid =3D 0
 > KDB: stack backtrace:
 > #0 0xffffffff8064e18e at ??+0
 > #1 0xffffffff8061b247 at ??+0
 > #2 0xffffffff80912ca0 at ??+0
 > #3 0xffffffff80913235 at ??+0
 > #4 0xffffffff808faad4 at ??+0
 > #5 0xffffffff80904cc2 at ??+0
 > #6 0xffffffff801a0244 at ??+0
 > =3D=3D=3D
 >=20
 > When booting from the latest 8-STABLE branch the booting process
 > just halts after the first panic line.
 >=20
 > The same problem can be observed in 9-STABLE, but I did not actually
 > bisect all the way to the relevant commit yet. However, r233702
 > seems a reasonable guess.
 >=20
 > Once the system is booted by reverting r233799, the following
 > processor information can be read:
 >=20
 >     CPU: Six-Core AMD Opteron(tm) Processor 2427 (2211.49-MHz K8-class CP=
 U)
 >       Origin =3D "AuthenticAMD"  Id =3D 0x100f80  Family =3D 10  Model =
 =3D 8  Stepping =3D 0
 >       Features=3D0x783fbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MT=
 RR,PGE,MCA,CMOV,PAT,PSE36,MMX,FXSR,SSE,SSE2>
 >       Features2=3D0x80802001<SSE3,CX16,POPCNT,HV>
 >       AMD Features=3D0xe6500800<SYSCALL,NX,MMX+,FFXSR,Page1GB,LM,3DNow!+,=
 3DNow!>
 >       AMD Features2=3D0x1f7<LAHF,CMP,SVM,CR8,ABM,SSE4A,MAS,Prefetch>
 >       TSC: P-state invariant
 >=20
 > Also, using x86info:
 >=20
 >     x86info v1.30.  Dave Jones 2001-2011
 >     Feedback to <davej at redhat.com>.
 >=20
 >     Extended Family: 1 Extended Model: 0 Family: 15 Model: 8 Stepping: 0
 >     CPU Model (x86info's best guess): Phenom/Athlon/Sempron/Turion (II)/O=
 pteron (HY-D0)
 >     Processor name string (BIOS programmed): Six-Core AMD Opteron(tm) Pro=
 cessor 2427
 >=20
 >     Monitor/Mwait: min/max line size 0/0, ecx bit 0 support, enumeration =
 extension
 >     SVM: revision 1, 16 ASIDs, np, NRIPSave
 >     Address Size: 48 bits virtual, 40 bits physical
 >     running at an estimated 2.35GHz
 >=20
 > Unfortunately I have no detailed information about the QEMU
 > configuration, but I set up a dedicated VM that I could use to test
 > patches.
 
 Try this. Comment should give enough explanation what happens there, my
 guess anyway.
 
 diff --git a/sys/amd64/amd64/initcpu.c b/sys/amd64/amd64/initcpu.c
 index 3890551..dbeaec6 100644
 --- a/sys/amd64/amd64/initcpu.c
 +++ b/sys/amd64/amd64/initcpu.c
 @@ -91,11 +91,17 @@ init_amd(void)
  	 *
  	 * http://support.amd.com/us/Processor_TechDocs/41322_10h_Rev_Gd.pdf
  	 * http://support.amd.com/us/Processor_TechDocs/44739_12h_Rev_Gd.pdf
 +	 *
 +	 * Hypervisors do not provide access to the errata MSR,
 +	 * causing #GP exception on attempt to apply the errata.  The
 +	 * MSR write shall be done on host and persist globally
 +	 * anyway, so do not try to do it when under virtualization.
  	 */
  	switch (CPUID_TO_FAMILY(cpu_id)) {
  	case 0x10:
  	case 0x12:
 -		wrmsr(0xc0011029, rdmsr(0xc0011029) | 1);
 +		if ((cpu_feature2 & CPUID2_HV) =3D=3D 0)
 +			wrmsr(0xc0011029, rdmsr(0xc0011029) | 1);
  		break;
  	}
  }
 
 
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