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authorSean Christopherson <sean.j.christopherson@intel.com>2019-04-25 19:01:09 -0700
committerPaolo Bonzini <pbonzini@redhat.com>2019-04-30 21:22:15 +0200
commitb904cb8dff824b79233e82c078837627ebd52717 (patch)
tree52455de1292a96b7b5d65f0b99556cfe69422d3d
parent76d58e0f07ec203bbdfcaabd9a9fc10a5a3ed5ea (diff)
KVM: lapic: Check for in-kernel LAPIC before deferencing apic pointer
...to avoid dereferencing a null pointer when querying the per-vCPU timer advance. Fixes: 39497d7660d98 ("KVM: lapic: Track lapic timer advance per vCPU") Reported-by: syzbot+f7e65445a40d3e0e4ebf@syzkaller.appspotmail.com Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-rw-r--r--arch/x86/kvm/lapic.c3
-rw-r--r--arch/x86/kvm/x86.c3
2 files changed, 2 insertions, 4 deletions
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index e0fa6fc0b2d8..bd13fdddbdc4 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1507,9 +1507,6 @@ void wait_lapic_expire(struct kvm_vcpu *vcpu)
u32 timer_advance_ns = apic->lapic_timer.timer_advance_ns;
u64 guest_tsc, tsc_deadline, ns;
- if (!lapic_in_kernel(vcpu))
- return;
-
if (apic->lapic_timer.expired_tscdeadline == 0)
return;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 57621313dead..b5edc8e3ce1d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7894,7 +7894,8 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
}
trace_kvm_entry(vcpu->vcpu_id);
- if (vcpu->arch.apic->lapic_timer.timer_advance_ns)
+ if (lapic_in_kernel(vcpu) &&
+ vcpu->arch.apic->lapic_timer.timer_advance_ns)
wait_lapic_expire(vcpu);
guest_enter_irqoff();