Re: [PATCH v1 12/27] xen/riscv: introduce aia_init() and aia_available()

[Jan Beulich <jbeulich@xxxxxxxx>]

On 13.04.2026 11:32, Oleksii Kurochko wrote:
> On 4/2/26 11:00 AM, Jan Beulich wrote:
>> On 10.03.2026 18:08, Oleksii Kurochko wrote:
>>> aia_init() is going to contain all the stuff related to AIA initialization.
>>> At the moment, it is just Check if SSAIA extension is available and if yes
>>> set is_aia_available to true.
>>
>> And (future) users of aia_available() can't directly call
>> riscv_isa_extension_available()? Nor can aia_available() be a convenience
>> wrapper around that call? It's only ...
>>
>>> --- /dev/null
>>> +++ b/xen/arch/riscv/aia.c
>>> @@ -0,0 +1,25 @@
>>> +/* SPDX-License-Identifier: GPL-2.0-only */
>>> +
>>> +#include <xen/errno.h>
>>> +#include <xen/init.h>
>>> +#include <xen/sections.h>
>>> +#include <xen/types.h>
>>> +
>>> +#include <asm/cpufeature.h>
>>> +
>>> +static bool __ro_after_init is_aia_available;
>>
>> ... a boolean, yes, but still.
> 
> My purpose was to have a variable which represent that AIA is 
> initialized properly. Maybe, it makes sense to rename this variable to 
> is_aia_inited.

I'm generally having trouble with the non-word "inited". How about
"aia_usable"? Fits ...

> The idea is that in future patches VGEIN will be also initialized in 
> aia_init() and if wasn't initialized properly then just keep 
> is_aia_availabe be set to false and in such case we will have that 
> is_aia_available != riscv_isa_extension_available(NULL, 
> RISCV_ISA_EXT_ssaia).

... this as well. And ...

> Note that regarding VGEIN it is arguable that it should be initialized 
> as generally it could be that there is no VGEIN what means that h/w 
> assisted guest interrupt files aren't available and s/w one should be 
> used. But s/w guest interrupt files aren't supported.
> So I mean that with the current implementation if VGEIN isn't 
> initialized I will tell that AIA isn't available what generally isn't 
> quite true.

... this. Question of course if what aia_usable (or whatever its name)
being set to false means to Xen's own operation. If Xen would still work
okay (without being able to create guests), perhaps the name may want to
be "aia_guest_usable" or some such. I.e. as I said on a number of
occasions: A variable wants to be named to accurately express its
purpose, without the name growing excessively long.

Jan