The patch below does not apply to the 4.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From b7e31be385584afe7f073130e8e570d53c95f7fe Mon Sep 17 00:00:00 2001

From: =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= rkrcmar@redhat.com Date: Thu, 1 Mar 2018 15:24:25 +0100 Subject: [PATCH] KVM: x86: fix vcpu initialization with userspace lapic MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit

Moving the code around broke this rare configuration. Use this opportunity to finally call lapic reset from vcpu reset.

Reported-by: syzbot+fb7a33a4b6c35007a72b@syzkaller.appspotmail.com Suggested-by: Paolo Bonzini pbonzini@redhat.com Fixes: 0b2e9904c159 ("KVM: x86: move LAPIC initialization after VMCS creation") Cc: stable@vger.kernel.org Signed-off-by: Radim Krčmář rkrcmar@redhat.com

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index cc5fe7a50dde..391dda8d43b7 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -2002,14 +2002,13 @@ void kvm_lapic_set_base(struct kvm_vcpu *vcpu, u64 value)

void kvm_lapic_reset(struct kvm_vcpu *vcpu, bool init_event) { - struct kvm_lapic *apic; + struct kvm_lapic *apic = vcpu->arch.apic; int i;

- apic_debug("%s\n", __func__); + if (!apic) + return;

- ASSERT(vcpu); - apic = vcpu->arch.apic; - ASSERT(apic != NULL); + apic_debug("%s\n", __func__);

/* Stop the timer in case it's a reset to an active apic */ hrtimer_cancel(&apic->lapic_timer.timer); @@ -2568,7 +2567,6 @@ void kvm_apic_accept_events(struct kvm_vcpu *vcpu)

pe = xchg(&apic->pending_events, 0); if (test_bit(KVM_APIC_INIT, &pe)) { - kvm_lapic_reset(vcpu, true); kvm_vcpu_reset(vcpu, true); if (kvm_vcpu_is_bsp(apic->vcpu)) vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 11649d290b93..18b5ca7a3197 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -8060,7 +8060,6 @@ 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; @@ -8103,6 +8102,8 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)

void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) { + kvm_lapic_reset(vcpu, init_event); + vcpu->arch.hflags = 0;

vcpu->arch.smi_pending = 0;