[PATCH 3.10 057/129] KVM: x86: Fix APIC map calculation after re-enabling

From: Greg Kroah-Hartman
Date: Mon Jan 06 2014 - 17:41:09 EST


3.10-stable review patch. If anyone has any objections, please let me know.

------------------

From: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>

commit e66d2ae7c67bd9ac982a3d1890564de7f7eabf4b upstream.

Update arch.apic_base before triggering recalculate_apic_map. Otherwise
the recalculation will work against the previous state of the APIC and
will fail to build the correct map when an APIC is hardware-enabled
again.

This fixes a regression of 1e08ec4a13.

Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
arch/x86/kvm/lapic.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1364,6 +1364,10 @@ void kvm_lapic_set_base(struct kvm_vcpu
return;
}

+ if (!kvm_vcpu_is_bsp(apic->vcpu))
+ value &= ~MSR_IA32_APICBASE_BSP;
+ vcpu->arch.apic_base = value;
+
/* update jump label if enable bit changes */
if ((vcpu->arch.apic_base ^ value) & MSR_IA32_APICBASE_ENABLE) {
if (value & MSR_IA32_APICBASE_ENABLE)
@@ -1373,10 +1377,6 @@ void kvm_lapic_set_base(struct kvm_vcpu
recalculate_apic_map(vcpu->kvm);
}

- if (!kvm_vcpu_is_bsp(apic->vcpu))
- value &= ~MSR_IA32_APICBASE_BSP;
-
- vcpu->arch.apic_base = value;
if ((old_value ^ value) & X2APIC_ENABLE) {
if (value & X2APIC_ENABLE) {
u32 id = kvm_apic_id(apic);


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