Re: [Qemu-arm] [Qemu-devel] [RFC 2/3] intc/arm_gic: Support PPI injection for more than 256 vpus

[Auger Eric]

Hi Peter,

On 9/3/19 10:29 AM, Peter Maydell wrote:
> On Thu, 29 Aug 2019 at 08:58, Auger Eric <address@hidden> wrote:
>>
>> Hi Zenghui,
>>
>> On 8/29/19 4:53 AM, Zenghui Yu wrote:
>>> For confirmation, should we also adjust the vcpu_index in
>>> arm_cpu_kvm_set_irq(), just like above?
>>
>> I am not familiar with this path. in arm_cpu_initfn(), there is a
>> comment saying "VIRQ and VFIQ are unused with KVM but we add them to
>> maintain the same interface as non-KVM CPUs." So I don't know when that
>> code gets executed.
> 
> That comment is saying that all KVM guest CPUs are
> EL1-only (since we don't handle nested virt), and therefore
> they logically don't have an inbound VIRQ or VFIQ line.
> But we provide the qemu_irqs for them anyway, so that
> board code doesn't have to have tedious conditionals
> saying "if this CPU has EL2 then wire up VIRQ and VFIQ
> to the GIC". If you ever try to actually assert the VIRQ
> or VFIQ lines you will hit the g_assert_not_reached() in
> arm_cpu_kvm_set_irq().

OK thanks for the clarification. I mixed things up.

I guess arm_cpu_kvm_set_irq attempting to inject IRQ/FIQ into KVM is
used with userspace GIC emulation, which is not supported along with
GICv3. But anyway, I guess it does not hurt to set vcpu_index2 in
arm_cpu_kvm_set_irq?

Thanks

Eric


> 
> thanks
> -- PMM
>