| Message ID | 1473832464-3478-1-git-send-email-wanpeng.li@hotmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
2016-09-14 13:54+0800, Wanpeng Li: > From: Wanpeng Li <wanpeng.li@hotmail.com> > > Add -kernel_irqchip=split > ./x86-run x86/eventinj.flat > > qemu-system-x86_64 -enable-kvm -machine kernel_irqchip=split -cpu host > -device pc-testdev -device isa-debug-exit,iobase=0xf4,iosize=0x4 -vnc > none -serial stdio -device pci-testdev -kernel x86/eventinj.flat > enabling apic > paging enabled > cr0 = 80010011 > cr3 = 7fff000 > cr4 = 20 > Sending vec 33 and 62 and mask one with TPR > irq1 running > irq1 running > After 33/62 TPR test > FAIL: TPR > irq0 running > irq0 running > > Both irq1 and irq0 are executing twice. > > kvm_entry: vcpu 0 > kvm_exit: reason MSR_WRITE rip 0x401f33 info 0 0 > kvm_apic: apic_write APIC_EOI = 0x0 > kvm_eoi: apicid 0 vector 62 > kvm_msr: msr_write 80b = 0x0 > kvm_entry: vcpu 0 > kvm_exit: reason PENDING_INTERRUPT rip 0x401f35 info 0 0 > kvm_userspace_exit: reason KVM_EXIT_IRQ_WINDOW_OPEN (7) > kvm_inj_virq: irq 62 > kvm_entry: vcpu 0 > kvm_exit: reason IO_INSTRUCTION rip 0x4016ec info 3fd0008 0 > > From the trace we can see there is an interrupt window exit > after the first interrupt EOI(irq 62), and the same irq(62) > is injected duplicately after the interrupt window. > > QEMU does KVM_INTERRUPT(62) ioctl after KVM exits with > KVM_EXIT_IRQ_WINDOW_OPEN, which QEMU requested while the > guest was printing. The printing calls > > serial_update_irq() -> qemu_irq_lower() -> qemu_set_irq() -> > gsi_handler() -> qemu_set_irq() -> pic_irq_request() -> > apic_deliver_pic_intr() -> kvm_handle_interrupt() > > kvm_handle_interrupt() does > > interrupt_request |= CPU_INTERRUPT_HARD > > which later calls cpu_get_pic_interrupt() in kvm_arch_pre_run(), > but that function uses stale information from APIC and injects > 62 again. If we synchronized the APIC, then the test would #GP, > because there would be no injectable interrupt in LAPIC or PIC, > so pic_read_irq() would return 15, thinking it was spurious. > > This patch fix it by don't touch LAPIC if LAPIC is in kernel. > > Suggested-by: Paolo Bonzini <pbonzini@redhat.com> > Suggested-by: Radim Krčmář <rkrcmar@redhat.com> > Cc: Paolo Bonzini <pbonzini@redhat.com> > Cc: Radim Krčmář <rkrcmar@redhat.com> > Cc: Michael S. Tsirkin <mst@redhat.com> > Cc: Eduardo Habkost <ehabkost@redhat.com> > Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> > --- Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
diff --git a/hw/i386/pc.c b/hw/i386/pc.c index e31f70f..4f3d508 100644 --- a/hw/i386/pc.c +++ b/hw/i386/pc.c @@ -161,14 +161,16 @@ int cpu_get_pic_interrupt(CPUX86State *env) X86CPU *cpu = x86_env_get_cpu(env); int intno; - intno = apic_get_interrupt(cpu->apic_state); - if (intno >= 0) { - return intno; - } - /* read the irq from the PIC */ - if (!apic_accept_pic_intr(cpu->apic_state)) { - return -1; - } + if (!kvm_irqchip_in_kernel()) { + intno = apic_get_interrupt(cpu->apic_state); + if (intno >= 0) { + return intno; + } + /* read the irq from the PIC */ + if (!apic_accept_pic_intr(cpu->apic_state)) { + return -1; + } + } intno = pic_read_irq(isa_pic); return intno; @@ -180,7 +182,7 @@ static void pic_irq_request(void *opaque, int irq, int level) X86CPU *cpu = X86_CPU(cs); DPRINTF("pic_irqs: %s irq %d\n", level? "raise" : "lower", irq); - if (cpu->apic_state) { + if (cpu->apic_state && !kvm_irqchip_in_kernel()) { CPU_FOREACH(cs) { cpu = X86_CPU(cs); if (apic_accept_pic_intr(cpu->apic_state)) {