aboutsummaryrefslogtreecommitdiffstats
path: root/arch/x86
diff options
context:
space:
mode:
authorYuki Shibuya <shibuya.yk@ncos.nec.co.jp>2016-03-24 05:17:03 +0000
committerPaolo Bonzini <pbonzini@redhat.com>2016-04-01 12:10:09 +0200
commit321c5658c5e9192dea0d58ab67cf1791e45b2b26 (patch)
tree3c5f9beb62f2a937adeaf511e74388cf7127ddc9 /arch/x86
parentMerge tag 'kvm-arm-for-4.6-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD (diff)
downloadlinux-dev-321c5658c5e9192dea0d58ab67cf1791e45b2b26.tar.xz
linux-dev-321c5658c5e9192dea0d58ab67cf1791e45b2b26.zip
KVM: x86: Inject pending interrupt even if pending nmi exist
Non maskable interrupts (NMI) are preferred to interrupts in current implementation. If a NMI is pending and NMI is blocked by the result of nmi_allowed(), pending interrupt is not injected and enable_irq_window() is not executed, even if interrupts injection is allowed. In old kernel (e.g. 2.6.32), schedule() is often called in NMI context. In this case, interrupts are needed to execute iret that intends end of NMI. The flag of blocking new NMI is not cleared until the guest execute the iret, and interrupts are blocked by pending NMI. Due to this, iret can't be invoked in the guest, and the guest is starved until block is cleared by some events (e.g. canceling injection). This patch injects pending interrupts, when it's allowed, even if NMI is blocked. And, If an interrupts is pending after executing inject_pending_event(), enable_irq_window() is executed regardless of NMI pending counter. Cc: stable@vger.kernel.org Signed-off-by: Yuki Shibuya <shibuya.yk@ncos.nec.co.jp> Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kvm/x86.c20
1 files changed, 10 insertions, 10 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 742d0f7d3556..0a2c70e43bc8 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6095,12 +6095,10 @@ static int inject_pending_event(struct kvm_vcpu *vcpu, bool req_int_win)
}
/* try to inject new event if pending */
- if (vcpu->arch.nmi_pending) {
- if (kvm_x86_ops->nmi_allowed(vcpu)) {
- --vcpu->arch.nmi_pending;
- vcpu->arch.nmi_injected = true;
- kvm_x86_ops->set_nmi(vcpu);
- }
+ if (vcpu->arch.nmi_pending && kvm_x86_ops->nmi_allowed(vcpu)) {
+ --vcpu->arch.nmi_pending;
+ vcpu->arch.nmi_injected = true;
+ kvm_x86_ops->set_nmi(vcpu);
} else if (kvm_cpu_has_injectable_intr(vcpu)) {
/*
* Because interrupts can be injected asynchronously, we are
@@ -6569,10 +6567,12 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
if (inject_pending_event(vcpu, req_int_win) != 0)
req_immediate_exit = true;
/* enable NMI/IRQ window open exits if needed */
- else if (vcpu->arch.nmi_pending)
- kvm_x86_ops->enable_nmi_window(vcpu);
- else if (kvm_cpu_has_injectable_intr(vcpu) || req_int_win)
- kvm_x86_ops->enable_irq_window(vcpu);
+ else {
+ if (vcpu->arch.nmi_pending)
+ kvm_x86_ops->enable_nmi_window(vcpu);
+ if (kvm_cpu_has_injectable_intr(vcpu) || req_int_win)
+ kvm_x86_ops->enable_irq_window(vcpu);
+ }
if (kvm_lapic_enabled(vcpu)) {
update_cr8_intercept(vcpu);