From: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
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 <vkuznets@xxxxxxxxxx>
Message-Id: <20220325132140.25650-2-vkuznets@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/hyperv.c | 3 +++
1 file changed, 3 insertions(+)
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -446,6 +446,9 @@ static int synic_set_irq(struct kvm_vcpu
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;
Patches currently in stable-queue which might be from vkuznets@xxxxxxxxxx are
queue-5.15/kvm-x86-avoid-theoretical-null-pointer-dereference-in-kvm_irq_delivery_to_apic_fast.patch
queue-5.15/kvm-x86-check-lapic_in_kernel-before-attempting-to-set-a-synic-irq.patch
queue-5.15/kvm-x86-hyper-v-drop-redundant-ex-parameter-from-kvm_hv_flush_tlb.patch
queue-5.15/kvm-x86-hyper-v-hvcall_send_ipi_ex-is-an-xmm-fast-hypercall.patch
queue-5.15/kvm-x86-hyper-v-fix-the-maximum-number-of-sparse-banks-for-xmm-fast-tlb-flush-hypercalls.patch
queue-5.15/kvm-x86-hyper-v-drop-redundant-ex-parameter-from-kvm_hv_send_ipi.patch
queue-5.15/kvm-x86-forbid-vmm-to-set-synic-stimer-msrs-when-synic-wasn-t-activated.patch
