Commit 0b2e9904 authored Feb 23, 2018 by Paolo Bonzini

KVM: x86: move LAPIC initialization after VMCS creation



The initial reset of the local APIC is performed before the VMCS has been
created, but it tries to do a vmwrite:

 vmwrite error: reg 810 value 4a00 (err 18944)
 CPU: 54 PID: 38652 Comm: qemu-kvm Tainted: G        W I      4.16.0-0.rc2.git0.1.fc28.x86_64 #1
 Hardware name: Intel Corporation S2600CW/S2600CW, BIOS SE5C610.86B.01.01.0003.090520141303 09/05/2014
 Call Trace:
  vmx_set_rvi [kvm_intel]
  vmx_hwapic_irr_update [kvm_intel]
  kvm_lapic_reset [kvm]
  kvm_create_lapic [kvm]
  kvm_arch_vcpu_init [kvm]
  kvm_vcpu_init [kvm]
  vmx_create_vcpu [kvm_intel]
  kvm_vm_ioctl [kvm]

Move it later, after the VMCS has been created.

Fixes: 4191db26 ("KVM: x86: Update APICv on APIC reset")
Cc: stable@vger.kernel.org
Cc: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

parent ee1a15e3

arch/x86/kvm/lapic.c

+0 −1

Original line number	Diff line number	Diff line
		@@ -2165,7 +2165,6 @@ int kvm_create_lapic(struct kvm_vcpu *vcpu)
		*/
		vcpu->arch.apic_base = MSR_IA32_APICBASE_ENABLE;
		static_key_slow_inc(&apic_sw_disabled.key); /* sw disabled at reset */
		kvm_lapic_reset(vcpu, false);
		kvm_iodevice_init(&apic->dev, &apic_mmio_ops);

		return 0;

arch/x86/kvm/x86.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -7975,6 +7975,7 @@ int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
		kvm_vcpu_mtrr_init(vcpu);
		vcpu_load(vcpu);
		kvm_vcpu_reset(vcpu, false);
		kvm_lapic_reset(vcpu, false);
		kvm_mmu_setup(vcpu);
		vcpu_put(vcpu);
		return 0;

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