From: Radim Krčmář Date: Fri, 22 May 2015 17:22:10 +0000 (+0200) Subject: KVM: x86: preserve x2APIC LDR on INIT X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=c028dd6bb648251b773f900f59e53544278b3b3c;p=deliverable%2Flinux.git KVM: x86: preserve x2APIC LDR on INIT Logical x2APIC stops working if we rewrite it with zeros. The best references are SDM April 2015: 10.12.10.1 Logical Destination Mode in x2APIC Mode [...], the LDR are initialized by hardware based on the value of x2APIC ID upon x2APIC state transitions. and SDM April 2015: 10.12.10.2 Deriving Logical x2APIC ID from the Local x2APIC ID The LDR initialization occurs whenever the x2APIC mode is enabled Signed-off-by: Radim Krčmář Signed-off-by: Paolo Bonzini --- diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index c2a7d8a7a414..c789e00dfa8b 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -1594,7 +1594,8 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu, bool init_event) apic_set_reg(apic, APIC_DFR, 0xffffffffU); apic_set_spiv(apic, 0xff); apic_set_reg(apic, APIC_TASKPRI, 0); - kvm_apic_set_ldr(apic, 0); + if (!apic_x2apic_mode(apic)) + kvm_apic_set_ldr(apic, 0); apic_set_reg(apic, APIC_ESR, 0); apic_set_reg(apic, APIC_ICR, 0); apic_set_reg(apic, APIC_ICR2, 0);