Messages in this thread | | | Subject | Re: [PATCH 2/2] KVM: x86: allow BSP to handle INIT IPIs like APs do | From | Paolo Bonzini <> | Date | Mon, 8 Feb 2016 16:12:23 +0100 |
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On 03/02/2016 23:51, Bruce Rogers wrote: > The INIT IPI event handler special cases the boot-strap processor > (BSP) handling, avoiding the same mp state handling which is done for > the other (AP) processors. Debugging a linux guest usage scenario of > avoiding a reboot through the bios for a crash on any processor via eg: > kexec -p /boot/vmlinuz --initrd=/boot/initrd --append="$(cat /proc/cmdline)\ > maxcpus=1" led to identifying this change as the needed fix. > > With this change, an AP can now startup the BSP without error. > > Signed-off-by: Bruce Rogers <brogers@suse.com> > --- > arch/x86/kvm/lapic.c | 5 +---- > 1 file changed, 1 insertion(+), 4 deletions(-) > > diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c > index 36591fa..eda6bfb 100644 > --- a/arch/x86/kvm/lapic.c > +++ b/arch/x86/kvm/lapic.c > @@ -2170,10 +2170,7 @@ void kvm_apic_accept_events(struct kvm_vcpu *vcpu) > if (test_bit(KVM_APIC_INIT, &pe)) { > kvm_lapic_reset(vcpu, true); > kvm_vcpu_reset(vcpu, true); > - if (kvm_vcpu_is_bsp(apic->vcpu)) > - vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE; > - else > - vcpu->arch.mp_state = KVM_MP_STATE_INIT_RECEIVED; > + vcpu->arch.mp_state = KVM_MP_STATE_INIT_RECEIVED; > } > if (test_bit(KVM_APIC_SIPI, &pe) && > vcpu->arch.mp_state == KVM_MP_STATE_INIT_RECEIVED) { >
KVM_MP_STATE_INIT_RECEIVED is what Intel calls the "wait for SIPI" state. The BSP never gets a SIPI, it goes straight to 0xFFFFFFF0 instead. Can you explain the problem more in detail?
Paolo
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