Re: [PATCH] Search the LAPIC's for one that will accept a PIC interrupt.

[Avi Kivity <avi@redhat.com>]

On 06/21/2010 06:29 PM, Chris Lalancette wrote:
> Older versions of 32-bit linux have a "Checking 'hlt' instruction"
> test where they repeatedly call the 'hlt' instruction, and then
> expect a timer interrupt to kick the CPU out of halt.  This happens
> before any LAPIC or IOAPIC setup happens, which means that all of
> the APIC's are in virtual wire mode at this point.  Unfortunately,
> the current implementation of virtual wire mode is hardcoded to
> only kick the BSP, so if a crash+kexec occurs on a different
> vcpu, it will never get kicked.
>
> This patch makes pic_unlock() do the equivalent of
> kvm_irq_delivery_to_apic() for the IOAPIC code.  That is, it runs
> through all of the vcpus looking for one that is in virtual wire
> mode.  In the normal case where LAPICs and IOAPICs are configured,
> this won't be used at all.  In the bootstrap phase of a modern
> OS, before the LAPICs and IOAPICs are configured, this will have
> exactly the same behavior as today; VCPU0 is always looked at
> first, so it will always get out of the loop after the first
> iteration.  This will only go through the loop more than once
> during a kexec/kdump, in which case it will only do it a few times
> until the kexec'ed kernel programs the LAPIC and IOAPIC.
>    

Applied, thanks.

-- 
error compiling committee.c: too many arguments to function