On Mon, Jun 21, 2010 at 11:29:40AM -0400, 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. > > Signed-off-by: Chris Lalancette <[email protected]> > --- > arch/x86/kvm/i8259.c | 17 +++++++++++++---- > 1 files changed, 13 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/kvm/i8259.c b/arch/x86/kvm/i8259.c > index 2c73f44..85ecabc 100644 > --- a/arch/x86/kvm/i8259.c > +++ b/arch/x86/kvm/i8259.c > @@ -44,16 +44,25 @@ static void pic_unlock(struct kvm_pic *s) > __releases(&s->lock) > { > bool wakeup = s->wakeup_needed; > - struct kvm_vcpu *vcpu; > + struct kvm_vcpu *vcpu, *found = NULL; > + int i; > > s->wakeup_needed = false; > > raw_spin_unlock(&s->lock); > > if (wakeup) { > - vcpu = s->kvm->bsp_vcpu; > - if (vcpu) > - kvm_vcpu_kick(vcpu); > + kvm_for_each_vcpu(i, vcpu, s->kvm) { > + if (kvm_apic_accept_pic_intr(vcpu)) { > + found = vcpu; > + break; > + } > + } Shouldn't we kick all vcpus that are in virtual write mode, not just first one found?
> + > + if (!found) > + found = s->kvm->bsp_vcpu; > + > + kvm_vcpu_kick(found); > } > } > > -- > 1.6.6.1 > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
