Re: [Qemu-devel] [PATCH v8 2/5] hw/intc/arm_gicv3_kvm: Add ICC_SRE_EL1 register to vmstate

[Vijay Kilari]

Hi Christoffer,

On Mon, Feb 20, 2017 at 3:21 PM, Peter Maydell <address@hidden> wrote:
> On 20 February 2017 at 06:21, Vijay Kilari <address@hidden> wrote:
>> Hi Peter,
>>
>> On Fri, Feb 17, 2017 at 7:25 PM, Peter Maydell <address@hidden> wrote:
> [on the guest-visible ICC_SRE_EL1 value]
>>> Is there a situation where KVM might allow a value other
>>> than 0x7?
>>
>> In KVM, the SRE_EL1 value is 0x1. During save, value
>> read from KVM is 0x1 though we reset to 0x7.
>
> 0x1 meanss "System Register Interface enabled, IRQ
> bypass enabled, FIQ bypass enabled". This seems
> rather a weird setting, because it means "the GICv3
> CPU interface functionality is disabled and the GICv3
> should signal interrupts via legacy IRQ and FIQ".
> Does KVM really support IRQ/FIQ bypass and does Linux
> really leave it enabled rather than turning it off
> by writing the value to 1?
>
> My expectation was that the KVM GICv3 emulation would
> make these bits RAO/WI like the TCG implementation.
> Is there maybe a bug in the kernel side where it
> doesn't implement bypass but has made these bits be
> RAZ/WI rather than RAO/WI ?

Do you have any inputs on this?