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

Kevin O'Connor
2015-03-11T19:19:31Z

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.

-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