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kvm: lapic: fix broken vcpu hotplug

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Guest fails to online hotplugged CPU with error
  smpboot: do_boot_cpu failed(-1) to wakeup CPU#4

It's caused by the fact that kvm_apic_set_state(), which used to call
recalculate_apic_map() unconditionally and pulled hotplugged CPU into
apic map, is updating map conditionally on state changes.  In this case
the APIC map is not considered dirty and the is not updated.

Fix the issue by forcing unconditional update from kvm_apic_set_state(),
like it used to be.

Fixes: 4abaffce4d ("KVM: LAPIC: Recalculate apic map in batch")
Cc: stable@vger.kernel.org
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20200622160830.426022-1-imammedo@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Igor Mammedov 2020-06-22 12:08:30 -04:00 committed by Paolo Bonzini
parent 49097762fa
commit af28dfacbe
1 changed files with 1 additions and 0 deletions
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arch/x86/kvm/lapic.c
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@ -2567,6 +2567,7 @@ int kvm_apic_set_state(struct kvm_vcpu *vcpu, struct kvm_lapic_state *s)
}
memcpy(vcpu->arch.apic->regs, s->regs, sizeof(*s));
apic->vcpu->kvm->arch.apic_map_dirty = true;
kvm_recalculate_apic_map(vcpu->kvm);
kvm_apic_set_version(vcpu);