Re: [Xen-devel] [PATCH v3 16/16] xen/arm: add SGI handling for GICv3

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Mon, 2014-05-05 at 19:40 +0100, Julien Grall wrote:

> As secure interrupt should not happen from the guest.

Surely it would be a silicon bug if it did, a secure interrupt should be
trapping to Secure EL3 not to NS EL2. What exactly are you asking Vijay
to handle here?

> You can check that 
> we correctly trap the access to thoses interrupts.

"trap access to interrupts" is meaningless AFAICT. Do you perhaps mean
"trap access to the XXX registers". For which XXX?

> >> The GICv3 spec requests to send a UNDEF exception if the register is not
> >> implemented.
> >>
> >> In general way, I think UNDEF is a best solution as some kernel such as
> >> Linux is able to recover from an undef on some specific access (it's
> >> actually the case for some debug registers on ARM32).
> >
> > In my understanding, calling inject_undef64_exception() will generate
> > UNDEF to guest.
> 
> Right. You have to call this function only if the domain is arm aarch64 
> guest.
> 
> AFAIU, it's possible to have GICv3 support when the guest is armv8 32 
> bit.

Is it? How do the system registers map onto the 32bit CP registers?

>  So you will have to call inject_undef32_exception for this case.

If it comes to this then please add inject_undef_exception which calls
the correct one for the guest type.

Ian.


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