Gleb Natapov wrote on 2013-04-07:
> On Sun, Apr 07, 2013 at 01:05:02PM +0000, Zhang, Yang Z wrote:
>> 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?
>>
> What is not obvious about it? If there is a bit in dest_map that should
> be cleared after rtc_irq_restore() it will not.
Why it will not? If new_val is false, and the old_val is true. __clear_bit() will clear the dest_map. Am I wrong?
new_val = kvm_apic_pending_eoi(vcpu, vector);
old_val = test_bit(vcpu->vcpu_id, ioapic->rtc_status.dest_map);
if (new_val == old_val)
return;
if (new_val) {
__set_bit(vcpu->vcpu_id, ioapic->rtc_status.dest_map);
ioapic->rtc_status.pending_eoi++;
} else {
__clear_bit(vcpu->vcpu_id, ioapic->rtc_status.dest_map);
ioapic->rtc_status.pending_eoi--;
}
Best regards,
Yang
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