KVM: x86: request interrupt window when IRQ chip is split

Before this patch, we incorrectly enter the guest without requesting an
interrupt window if the IRQ chip is split between user space and the
kernel.

Because lapic_in_kernel no longer implies the PIC is in the kernel, this
patch tests pic_in_kernel to determining whether an interrupt window
should be requested when entering the guest.

If the APIC is in the kernel and we request an interrupt window the
guest will return immediately. If the APIC is masked the guest will not
not make forward progress and unmask it, leading to a loop when KVM
reenters and requests again. This patch adds a check to ensure the APIC
is ready to accept an interrupt before requesting a window.

Reviewed-by: Steve Rutherford <srutherford@google.com>
Signed-off-by: Matt Gingell <gingell@google.com>
[Use the other newly introduced functions. - Paolo]
Fixes: 1c1a9ce973a7863dd46767226bce2a5f12d48bc6
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index f254e296d368fe299e32d403e1c32aff7ac95b91..eed32283d22cc0cafbff75e8f2a246887d4cbb5f 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6360,8 +6360,10 @@ void kvm_arch_mmu_notifier_invalidate_page(struct kvm *kvm,
 static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 {
        int r;
-       bool req_int_win = !lapic_in_kernel(vcpu) &&
-               vcpu->run->request_interrupt_window;
+       bool req_int_win =
+               dm_request_for_irq_injection(vcpu) &&
+               kvm_cpu_accept_dm_intr(vcpu);
+
        bool req_immediate_exit = false;
 
        if (vcpu->requests) {