[PATCH v1 2/2] x86, apic: Disable BSP if boot cpu is AP

H. Peter Anvin hpa at zytor.com
Mon Oct 22 16:33:01 EDT 2012

On 10/22/2012 01:31 PM, Eric W. Biederman wrote:
>> IIRC Fenghua experimented with that and it didn't work.  Not all BIOSes
>> use that bit to determine BSP-ness.
> What does a BIOS have to do with anything?
> The practical issue here is does an INIT IPI cause the cpu to go into
> startup-ipi-wait or to start booting at 4G-16 bytes.
> For dealing with BIOSen we may still need to use the bootstrap processor
> for firmware calls, cpu suspend, and other firmware weirdness, but that
> should all be completely orthogonal to the behavior to what happens
> when an INIT IPI is sent to the cpu.
> The only firmware problem I can imagine having is cpu virtualization
> bug.

The whole problem is that some BIOSes go wonky after receiving an INIT
(as in INIT-SIPI-SIPI) to the BSP.


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