[PATCH 5.10 62/95] KVM: nVMX: promptly process interrupts delivered while in guest mode

Greg Kroah-Hartman
2021-10-25T19:42:45Z

From: Paolo Bonzini <pbonzini@redhat.com>

commit 3a25dfa67fe40f3a2690af2c562e0947a78bd6a0 upstream.

Since commit c300ab9f08df ("KVM: x86: Replace late check_nested_events() hack with
more precise fix") there is no longer the certainty that check_nested_events()
tries to inject an external interrupt vmexit to L1 on every call to vcpu_enter_guest.
Therefore, even in that case we need to set KVM_REQ_EVENT. This ensures
that inject_pending_event() is called, and from there kvm_check_nested_events().

Fixes: c300ab9f08df ("KVM: x86: Replace late check_nested_events() hack with more precise fix")
Cc: stable@vger.kernel.org
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kvm/vmx/vmx.c | 17 ++++++-----------
1 file changed, 6 insertions(+), 11 deletions(-)

--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6316,18 +6316,13 @@ static int vmx_sync_pir_to_irr(struct kv

/*
* If we are running L2 and L1 has a new pending interrupt
- * which can be injected, we should re-evaluate
- * what should be done with this new L1 interrupt.
- * If L1 intercepts external-interrupts, we should
- * exit from L2 to L1. Otherwise, interrupt should be
- * delivered directly to L2.
+ * which can be injected, this may cause a vmexit or it may
+ * be injected into L2. Either way, this interrupt will be
+ * processed via KVM_REQ_EVENT, not RVI, because we do not use
+ * virtual interrupt delivery to inject L1 interrupts into L2.
*/
- if (is_guest_mode(vcpu) && max_irr_updated) {
- if (nested_exit_on_intr(vcpu))
- kvm_vcpu_exiting_guest_mode(vcpu);
- else
- kvm_make_request(KVM_REQ_EVENT, vcpu);
- }
+ if (is_guest_mode(vcpu) && max_irr_updated)
+ kvm_make_request(KVM_REQ_EVENT, vcpu);
} else {
max_irr = kvm_lapic_find_highest_irr(vcpu);
}