[PATCH 2/2] KVM: x86: allow BSP to handle INIT IPIs like APs do

From: Bruce Rogers
Date: Wed Feb 03 2016 - 18:12:43 EST


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@xxxxxxxx>
---
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) {
--
1.9.0