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Commit 257b9a5f authored by Radim Krčmář's avatar Radim Krčmář Committed by Paolo Bonzini
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KVM: x86: use correct APIC ID on x2APIC transition 



SDM April 2015, 10.12.5 State Changes From xAPIC Mode to x2APIC Mode
• Any APIC ID value written to the memory-mapped local APIC ID register
  is not preserved.

Fix it by sourcing vcpu_id (= initial APIC ID) instead of memory-mapped
APIC ID.  Proper use of apic functions would result in two calls to
recalculate_apic_map(), so this patch makes a new helper.

Signed-off-by: default avatarRadim Krčmář <rkrcmar@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 630994b3

arch/x86/kvm/lapic.c

+10 −3
Original line number Diff line number Diff line
@@ -240,6 +240,15 @@ static inline void kvm_apic_set_ldr(struct kvm_lapic *apic, u32 id) 
	recalculate_apic_map(apic->vcpu->kvm);

}



static inline void kvm_apic_set_x2apic_id(struct kvm_lapic *apic, u8 id)

{

	u32 ldr = ((id >> 4) << 16) | (1 << (id & 0xf));



	apic_set_reg(apic, APIC_ID, id << 24);

	apic_set_reg(apic, APIC_LDR, ldr);

	recalculate_apic_map(apic->vcpu->kvm);

}



static inline int apic_lvt_enabled(struct kvm_lapic *apic, int lvt_type)

{

	return !(kvm_apic_get_reg(apic, lvt_type) & APIC_LVT_MASKED);
@@ -1538,9 +1547,7 @@ void kvm_lapic_set_base(struct kvm_vcpu *vcpu, u64 value) 


	if ((old_value ^ value) & X2APIC_ENABLE) {

		if (value & X2APIC_ENABLE) {

			u32 id = kvm_apic_id(apic);

			u32 ldr = ((id >> 4) << 16) | (1 << (id & 0xf));

			kvm_apic_set_ldr(apic, ldr);

			kvm_apic_set_x2apic_id(apic, vcpu->vcpu_id);

			kvm_x86_ops->set_virtual_x2apic_mode(vcpu, true);

		} else

			kvm_x86_ops->set_virtual_x2apic_mode(vcpu, false);