Re: 2.6.35 hangs on early boot in KVM
From: Tvrtko Ursulin
Date: Wed Aug 04 2010 - 06:47:09 EST
On Wednesday 04 Aug 2010 11:37:43 Eric W. Biederman wrote:
> Gleb Natapov <gleb@xxxxxxxxxx> writes:
> > On Wed, Aug 04, 2010 at 10:16:08AM +0100, Tvrtko Ursulin wrote:
> >> Not the tip but 2.6.35 with earlyprintk=ttyS0,115200:
> >> [ 0.000000] Processor #0 (Bootup-CPU)
> >> [ 0.000000] I/O APIC #1 Version 17 at 0xFEC00000.
> >> [ 0.000000] BUG: unable to handle kernel paging request at ffffb030
> >> [ 0.000000] IP: [<c011d136>] native_apic_mem_read+0x16/0x20
> >> [ 0.000000] *pde = 00832067 *pte = 00000000
> > Accessing APIC version register before APIC is mapped.
> Yep. I see it now. We have some of the silliest code. We only
> go down this path for certain revs of Intel cpus, and I double checked
> this change on an AMD cpu which explains why I missed hitting this
> The call path that is new in they bisected commit is:
> Tvrtko can you test this patch and verify it fixes the kvm booting
> This patch just maps the lapic early in the mmparse.c just like we
> do in acpi/boot.c when parsing the acpi tables.
Boots fine, thanks!
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