summaryrefslogtreecommitdiff
path: root/arch/x86/kvm/irq.c
diff options
context:
space:
mode:
authorWanpeng Li <wanpeng.li@linux.intel.com>2014-08-05 12:42:24 +0800
committerPaolo Bonzini <pbonzini@redhat.com>2014-08-05 15:00:24 +0200
commit56cc2406d68c0f09505c389e276f27a99f495cbd (patch)
tree90e2d04ea45d9a22023ca6371dfc878cf4b70c2e /arch/x86/kvm/irq.c
parentf3380ca5d7edb5e31932998ab2e29dfdce39c5ed (diff)
KVM: nVMX: fix "acknowledge interrupt on exit" when APICv is in use
After commit 77b0f5d (KVM: nVMX: Ack and write vector info to intr_info if L1 asks us to), "Acknowledge interrupt on exit" behavior can be emulated. To do so, KVM will ask the APIC for the interrupt vector if during a nested vmexit if VM_EXIT_ACK_INTR_ON_EXIT is set. With APICv, kvm_get_apic_interrupt would return -1 and give the following WARNING: Call Trace: [<ffffffff81493563>] dump_stack+0x49/0x5e [<ffffffff8103f0eb>] warn_slowpath_common+0x7c/0x96 [<ffffffffa059709a>] ? nested_vmx_vmexit+0xa4/0x233 [kvm_intel] [<ffffffff8103f11a>] warn_slowpath_null+0x15/0x17 [<ffffffffa059709a>] nested_vmx_vmexit+0xa4/0x233 [kvm_intel] [<ffffffffa0594295>] ? nested_vmx_exit_handled+0x6a/0x39e [kvm_intel] [<ffffffffa0537931>] ? kvm_apic_has_interrupt+0x80/0xd5 [kvm] [<ffffffffa05972ec>] vmx_check_nested_events+0xc3/0xd3 [kvm_intel] [<ffffffffa051ebe9>] inject_pending_event+0xd0/0x16e [kvm] [<ffffffffa051efa0>] vcpu_enter_guest+0x319/0x704 [kvm] To fix this, we cannot rely on the processor's virtual interrupt delivery, because "acknowledge interrupt on exit" must only update the virtual ISR/PPR/IRR registers (and SVI, which is just a cache of the virtual ISR) but it should not deliver the interrupt through the IDT. Thus, KVM has to deliver the interrupt "by hand", similar to the treatment of EOI in commit fc57ac2c9ca8 (KVM: lapic: sync highest ISR to hardware apic on EOI, 2014-05-14). The patch modifies kvm_cpu_get_interrupt to always acknowledge an interrupt; there are only two callers, and the other is not affected because it is never reached with kvm_apic_vid_enabled() == true. Then it modifies apic_set_isr and apic_clear_irr to update SVI and RVI in addition to the registers. Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Suggested-by: "Zhang, Yang Z" <yang.z.zhang@intel.com> Tested-by: Liu, RongrongX <rongrongx.liu@intel.com> Tested-by: Felipe Reyes <freyes@suse.com> Fixes: 77b0f5d67ff2781f36831cba79674c3e97bd7acf Cc: stable@vger.kernel.org Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/irq.c')
-rw-r--r--arch/x86/kvm/irq.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kvm/irq.c b/arch/x86/kvm/irq.c
index bd0da433e6d7..a1ec6a50a05a 100644
--- a/arch/x86/kvm/irq.c
+++ b/arch/x86/kvm/irq.c
@@ -108,7 +108,7 @@ int kvm_cpu_get_interrupt(struct kvm_vcpu *v)
vector = kvm_cpu_get_extint(v);
- if (kvm_apic_vid_enabled(v->kvm) || vector != -1)
+ if (vector != -1)
return vector; /* PIC */
return kvm_get_apic_interrupt(v); /* APIC */