From a4bd692a950ada6d9757dbb78a6aea129ff8a943 Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Wed, 10 Aug 2022 23:26:54 +0300 Subject: [PATCH] KVM: x86: Check lapic_in_kernel() before attempting to set a SynIC irq commit 7ec37d1cbe17d8189d9562178d8b29167fe1c31a upstream When KVM_CAP_HYPERV_SYNIC{,2} is activated, KVM already checks for irqchip_in_kernel() so normally SynIC irqs should never be set. It is, however, possible for a misbehaving VMM to write to SYNIC/STIMER MSRs causing erroneous behavior. The immediate issue being fixed is that kvm_irq_delivery_to_apic() (kvm_irq_delivery_to_apic_fast()) crashes when called with 'irq.shorthand = APIC_DEST_SELF' and 'src == NULL'. Signed-off-by: Vitaly Kuznetsov Message-Id: <20220325132140.25650-2-vkuznets@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini Signed-off-by: Stefan Ghinea Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/hyperv.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index 5497eeef4e70..ae9c45590b7e 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -317,6 +317,9 @@ static int synic_set_irq(struct kvm_vcpu_hv_synic *synic, u32 sint) struct kvm_lapic_irq irq; int ret, vector; + if (KVM_BUG_ON(!lapic_in_kernel(vcpu), vcpu->kvm)) + return -EINVAL; + if (sint >= ARRAY_SIZE(synic->sint)) return -EINVAL; -- 2.20.1