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Commit 58d269d8 authored by Nadav Amit's avatar Nadav Amit Committed by Paolo Bonzini
Browse files

KVM: x86: BSP in MSR_IA32_APICBASE is writable 



After reset, the CPU can change the BSP, which will be used upon INIT.  Reset
should return the BSP which QEMU asked for, and therefore handled accordingly.

To quote: "If the MP protocol has completed and a BSP is chosen, subsequent
INITs (either to a specific processor or system wide) do not cause the MP
protocol to be repeated."
[Intel SDM 8.4.2: MP Initialization Protocol Requirements and Restrictions]

Signed-off-by: default avatarNadav Amit <namit@cs.technion.ac.il>
Message-Id: <1427933438-12782-3-git-send-email-namit@cs.technion.ac.il>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 3b5a5ffa

arch/x86/kvm/lapic.c

+0 −2
Original line number Diff line number Diff line
@@ -1523,8 +1523,6 @@ void kvm_lapic_set_base(struct kvm_vcpu *vcpu, u64 value) 
		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 */

arch/x86/kvm/svm.c

+1 −1
Original line number Diff line number Diff line
@@ -1261,7 +1261,7 @@ static struct kvm_vcpu *svm_create_vcpu(struct kvm *kvm, unsigned int id) 


	svm->vcpu.arch.apic_base = APIC_DEFAULT_PHYS_BASE |

				   MSR_IA32_APICBASE_ENABLE;

	if (kvm_vcpu_is_bsp(&svm->vcpu))

	if (kvm_vcpu_is_reset_bsp(&svm->vcpu))

		svm->vcpu.arch.apic_base |= MSR_IA32_APICBASE_BSP;



	svm_init_osvw(&svm->vcpu);

arch/x86/kvm/vmx.c

+1 −1
Original line number Diff line number Diff line
@@ -4706,7 +4706,7 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu) 
	vmx->vcpu.arch.regs[VCPU_REGS_RDX] = get_rdx_init_val();

	kvm_set_cr8(&vmx->vcpu, 0);

	apic_base_msr.data = APIC_DEFAULT_PHYS_BASE | MSR_IA32_APICBASE_ENABLE;

	if (kvm_vcpu_is_bsp(&vmx->vcpu))

	if (kvm_vcpu_is_reset_bsp(&vmx->vcpu))

		apic_base_msr.data |= MSR_IA32_APICBASE_BSP;

	apic_base_msr.host_initiated = true;

	kvm_set_apic_base(&vmx->vcpu, &apic_base_msr);

arch/x86/kvm/x86.c

+1 −1
Original line number Diff line number Diff line
@@ -7269,7 +7269,7 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu) 


	vcpu->arch.pv.pv_unhalted = false;

	vcpu->arch.emulate_ctxt.ops = &emulate_ops;

	if (!irqchip_in_kernel(kvm) || kvm_vcpu_is_bsp(vcpu))

	if (!irqchip_in_kernel(kvm) || kvm_vcpu_is_reset_bsp(vcpu))

		vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;

	else

		vcpu->arch.mp_state = KVM_MP_STATE_UNINITIALIZED;

include/linux/kvm_host.h

+6 −1
Original line number Diff line number Diff line
@@ -982,11 +982,16 @@ static inline int kvm_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args) 
#endif /* CONFIG_HAVE_KVM_EVENTFD */



#ifdef CONFIG_KVM_APIC_ARCHITECTURE

static inline bool kvm_vcpu_is_bsp(struct kvm_vcpu *vcpu)

static inline bool kvm_vcpu_is_reset_bsp(struct kvm_vcpu *vcpu)

{

	return vcpu->kvm->bsp_vcpu_id == vcpu->vcpu_id;

}



static inline bool kvm_vcpu_is_bsp(struct kvm_vcpu *vcpu)

{

	return (vcpu->arch.apic_base & MSR_IA32_APICBASE_BSP) != 0;

}



bool kvm_vcpu_compatible(struct kvm_vcpu *vcpu);



#else