From: Julien Grall <julien@xen.org>
To: "Stefano Stabellini" <sstabellini@kernel.org>,
"Andrew Cooper" <andrew.cooper3@citrix.com>,
"George Dunlap" <george.dunlap@citrix.com>,
"Ian Jackson" <ian.jackson@eu.citrix.com>, "Wei Liu" <wl@xen.org>,
"Roger Pau Monné" <roger.pau@citrix.com>
Cc: xen-devel@lists.xenproject.org, Julien Grall <jgrall@amazon.com>,
Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>,
Jan Beulich <jbeulich@suse.com>
Subject: Re: [PATCH 6/7] xen/guest_access: Consolidate guest access helpers in xen/guest_access.h
Date: Sat, 16 May 2020 11:25:48 +0100 [thread overview]
Message-ID: <aa209d94-2b39-7932-919b-9842f376e0dc@xen.org> (raw)
In-Reply-To: <c38f4581-42a6-bb4a-1f84-066528edd3ee@xen.org>
Ping 2.
On 29/04/2020 15:04, Julien Grall wrote:
> Hi,
>
> Gentle ping. Any comments on the direction to take?
>
> On 09/04/2020 10:28, Julien Grall wrote:
>>
>>
>> On 09/04/2020 09:06, Jan Beulich wrote:
>>> On 09.04.2020 10:01, Julien Grall wrote:
>>>> Hi,
>>>>
>>>> On 09/04/2020 07:30, Jan Beulich wrote:
>>>>> On 09.04.2020 00:05, Julien Grall wrote:
>>>>> I don't see why a new port may not also want
>>>>> to go that route instead of the x86/Arm one.
>>>> I could accept that someone would want to reinvent a new ABI
>>>> from scratch for just an hypothetical new arch. However it would
>>>> be quite an effort to reinvent XEN_GUEST_HANDLE(). The chance is
>>>> RISC-V is only going to re-use what Arm did as Arm already did
>>>> with x86.
>>>>
>>>> I would like to avoid to introduce a new directory asm-generic
>>>> with just one header in it. Maybe you have some other headers in
>>>> mind?
>>>
>>> I recall having wondered a few times whether we shouldn't use this
>>> concept elsewhere. One case iirc was bitops stuff. Looking over
>>> the Linux ones, some atomic and barrier fallback implementations
>>> may also sensibly live there, and there are likely more.
>>
>> In theory it makes sense but, in the current state of Xen,
>> 'asm-generic' means they are common to Arm and x86. This is basically
>> the same definition as for the directory 'xen'. So how do you draw a
>> line which files go where?
>>
>> To be honest, I don't think we can draw a line without a 3rd
>> architecture. So I would recommend to wait until then to create an
>> asm-generic directory.
>>
>> Meanwhile, I still think the consolidation in xen/ is useful as it
>> makes easier to maintain. It is also going to make easier for RISCv
>> (or a new arch) as they don't have to worry about duplication (if any).
>>
>> In the event they decide to purse their own route, then it is not
>> going to be a massive pain to move part of xen/guest_access.h in
>> asm-generic/guest_access.h and include the latter from {xen, asm}
>> /guest_access.h.
>
> Cheers,
>
--
Julien Grall
next prev parent reply other threads:[~2020-05-16 10:26 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-04 13:10 [PATCH 0/7] xen: Consolidate asm-*/guest_access.h in xen/guest_access.h Julien Grall
2020-04-04 13:10 ` [PATCH 1/7] xen/guest_access: Add missing emacs magics Julien Grall
2020-04-07 8:05 ` Jan Beulich
2020-04-08 21:43 ` Julien Grall
2020-04-04 13:10 ` [PATCH 2/7] xen/arm: kernel: Re-order the includes Julien Grall
2020-04-04 13:10 ` [PATCH 3/7] xen/arm: decode: " Julien Grall
2020-04-04 13:10 ` [PATCH 4/7] xen/arm: guestcopy: " Julien Grall
2020-04-04 13:10 ` [PATCH 5/7] xen: include xen/guest_access.h rather than asm/guest_access.h Julien Grall
2020-04-06 7:40 ` Paul Durrant
2020-04-06 8:51 ` Julien Grall
2020-04-04 13:10 ` [PATCH 6/7] xen/guest_access: Consolidate guest access helpers in xen/guest_access.h Julien Grall
2020-04-07 8:14 ` Jan Beulich
2020-04-08 22:05 ` Julien Grall
2020-04-09 6:30 ` Jan Beulich
2020-04-09 8:01 ` Julien Grall
2020-04-09 8:06 ` Jan Beulich
2020-04-09 9:28 ` Julien Grall
2020-04-29 14:04 ` Julien Grall
2020-04-29 14:07 ` Jan Beulich
2020-04-29 14:13 ` Julien Grall
2020-04-29 14:54 ` Jan Beulich
2020-04-29 15:03 ` Julien Grall
2020-05-16 10:25 ` Julien Grall [this message]
2020-05-19 15:05 ` Ian Jackson
2020-05-29 11:45 ` Julien Grall
2020-04-04 13:10 ` [PATCH 7/7] xen/guest_access: Fix coding style " Julien Grall
2020-04-07 8:17 ` Jan Beulich
2020-04-07 9:08 ` Julien Grall
2020-04-04 13:13 ` [PATCH 0/7] xen: Consolidate asm-*/guest_access.h " Julien Grall
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