Gleb Natapov wrote on 2013-04-07:
> On Sun, Apr 07, 2013 at 12:39:32PM +0000, Zhang, Yang Z wrote:
>> Gleb Natapov wrote on 2013-04-07:
>>> On Sun, Apr 07, 2013 at 02:30:15AM +0000, Zhang, Yang Z wrote:
>>>> Gleb Natapov wrote on 2013-04-04:
>>>>> On Mon, Apr 01, 2013 at 08:40:13AM +0800, Yang Zhang wrote:
>>>>>> From: Yang Zhang <yang.z.zhang@xxxxxxxxx>
>>>>>>
>>>>>> Signed-off-by: Yang Zhang <yang.z.zhang@xxxxxxxxx>
>>>>>> ---
>>>>>> arch/x86/kvm/lapic.c | 9 +++++++++ arch/x86/kvm/lapic.h | 2
>>>>>> ++ virt/kvm/ioapic.c | 43
>>>>>> +++++++++++++++++++++++++++++++++++++++++++ virt/kvm/ioapic.h | 1
>>>>>> + 4 files changed, 55 insertions(+), 0 deletions(-)
>>>>>> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
>>>>>> index 96ab160..9c041fa 100644
>>>>>> --- a/arch/x86/kvm/lapic.c
>>>>>> +++ b/arch/x86/kvm/lapic.c
>>>>>> @@ -94,6 +94,14 @@ static inline int apic_test_vector(int vec, void
> *bitmap)
>>>>>> return test_bit(VEC_POS(vec), (bitmap) + REG_POS(vec));
>>>>>> }
>>>>>> +bool kvm_apic_pending_eoi(struct kvm_vcpu *vcpu, int vector)
>>>>>> +{
>>>>>> + struct kvm_lapic *apic = vcpu->arch.apic;
>>>>>> +
>>>>>> + return apic_test_vector(vector, apic->regs + APIC_ISR) ||
>>>>>> + apic_test_vector(vector, apic->regs + APIC_IRR);
>>>>>> +}
>>>>>> +
>>>>>> static inline void apic_set_vector(int vec, void *bitmap)
>>>>>> {
>>>>>> set_bit(VEC_POS(vec), (bitmap) + REG_POS(vec));
>>>>>> @@ -1665,6 +1673,7 @@ void kvm_apic_post_state_restore(struct
>>> kvm_vcpu
>>>>> *vcpu,
>>>>>> apic->highest_isr_cache = -1;
>>>>>> kvm_x86_ops->hwapic_isr_update(vcpu->kvm,
>>>>>> apic_find_highest_isr(apic)); kvm_make_request(KVM_REQ_EVENT,
>>>>>> vcpu); + kvm_rtc_irq_restore(vcpu); }
>>>>>>
>>>>>> void __kvm_migrate_apic_timer(struct kvm_vcpu *vcpu)
>>>>>> diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
>>>>>> index 967519c..004d2ad 100644
>>>>>> --- a/arch/x86/kvm/lapic.h
>>>>>> +++ b/arch/x86/kvm/lapic.h
>>>>>> @@ -170,4 +170,6 @@ static inline bool kvm_apic_has_events(struct
>>>>> kvm_vcpu *vcpu)
>>>>>> return vcpu->arch.apic->pending_events;
>>>>>> }
>>>>>> +bool kvm_apic_pending_eoi(struct kvm_vcpu *vcpu, int vector);
>>>>>> +
>>>>>> #endif
>>>>>> diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
>>>>>> index 8664812..0b12b17 100644
>>>>>> --- a/virt/kvm/ioapic.c
>>>>>> +++ b/virt/kvm/ioapic.c
>>>>>> @@ -90,6 +90,47 @@ static unsigned long ioapic_read_indirect(struct
>>>>> kvm_ioapic *ioapic,
>>>>>> return result;
>>>>>> }
>>>>>> +static void rtc_irq_reset(struct kvm_ioapic *ioapic)
>>>>>> +{
>>>>>> + ioapic->rtc_status.pending_eoi = 0;
>>>>>> + bitmap_zero(ioapic->rtc_status.dest_map, KVM_MAX_VCPUS);
>>>>>> +}
>>>>>> +
>>>>>> +static void rtc_irq_restore(struct kvm_ioapic *ioapic)
>>>>>> +{
>>>>>> + struct kvm_vcpu *vcpu;
>>>>>> + int vector, i, pending_eoi = 0;
>>>>>> +
>>>>>> + if (RTC_GSI >= IOAPIC_NUM_PINS)
>>>>>> + return;
>>>>>> +
>>>>>> + vector = ioapic->redirtbl[RTC_GSI].fields.vector;
>>>>>> + kvm_for_each_vcpu(i, vcpu, ioapic->kvm) {
>>>>>> + if (kvm_apic_pending_eoi(vcpu, vector)) {
>>>>>> + pending_eoi++;
>>>>>> + __set_bit(vcpu->vcpu_id, ioapic->rtc_status.dest_map);
>>>>> You should cleat dest_map at the beginning to get rid of stale bits.
>>>> I thought kvm_set_ioapic is called only after save/restore or migration. And
> the
>>> ioapic should be reset successfully before call it. So the dest_map is empty
>>> before call rtc_irq_restore().
>>>> But it is possible kvm_set_ioapic is called beside save/restore or
>>>> migration. Right?
>>>>
>>> First of all userspace should not care when it calls kvm_set_ioapic()
>>> the kernel need to do the right thing. Second, believe it or not,
>>> kvm_ioapic_reset() is not called during system reset. Instead userspace
>>> reset it by calling kvm_set_ioapic() with ioapic state after reset.
>> Ok. I see. As the logic you suggested, it will clear dest_map if no
>> pending eoi in vcpu, so we don't need to do it again.
>>
> You again rely on userspace doing thing in certain manner. What is
> set_lapic() is never called? Kernel internal state have to be correct
> after each ioctl call.
Sorry. I cannot figure out what's the problem if don't clear dest_map? Can you elaborate it?
Best regards,
Yang
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