Re: [Qemu-devel] E5-2620v2 - emulation stop error

Dr. David Alan Gilbert
2015-03-11T19:33:45Z

* Kevin O'Connor (kevin@koconnor.net) wrote:
> On Wed, Mar 11, 2015 at 02:45:31PM -0400, Kevin O'Connor wrote:
> > On Wed, Mar 11, 2015 at 02:40:39PM -0400, Kevin O'Connor wrote:
> > > For what it's worth, I can't seem to trigger the problem if I move the
> > > cmos read above the SIPI/LAPIC code (see patch below).
> >
> > Ugh!
> >
> > That's a seabios bug. Main processor modifies the rtc index
> > (rtc_read()) while APs try to clear the NMI bit by modifying the rtc
> > index (romlayout.S:transition32).
> >
> > I'll put together a fix.
>
> The seabios patch below resolves the issue for me.

Thanks! Looks good here.

Andrey, Paolo, Bandan: Does it fix it for you as well?

Dave

> -Kevin
>
>
> --- a/src/romlayout.S
> +++ b/src/romlayout.S
> @@ -22,7 +22,8 @@
> // %edx = return location (in 32bit mode)
> // Clobbers: ecx, flags, segment registers, cr0, idt/gdt
> DECLFUNC transition32
> -transition32_for_smi:
> +transition32_nmi_off:
> + // transition32 when NMI and A20 are already initialized
> movl %eax, %ecx
> jmp 1f
> transition32:
> @@ -205,7 +206,7 @@ __farcall16:
> entry_smi:
> // Transition to 32bit mode.
> movl $1f + BUILD_BIOS_ADDR, %edx
> - jmp transition32_for_smi
> + jmp transition32_nmi_off
> .code32
> 1: movl $BUILD_SMM_ADDR + 0x8000, %esp
> calll _cfunc32flat_handle_smi - BUILD_BIOS_ADDR
> @@ -216,8 +217,10 @@ entry_smi:
> DECLFUNC entry_smp
> entry_smp:
> // Transition to 32bit mode.
> + cli
> + cld
> movl $2f + BUILD_BIOS_ADDR, %edx
> - jmp transition32
> + jmp transition32_nmi_off
> .code32
> // Acquire lock and take ownership of shared stack
> 1: rep ; nop
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK