Re: [PATCH 6/7] xen/guest_access: Consolidate guest access helpers in xen/guest_access.h

From: Julien Grall <julien@xen.org>
To: Jan Beulich <jbeulich@suse.com>
Cc: "Stefano Stabellini" <sstabellini@kernel.org>,
	"Wei Liu" <wl@xen.org>,
	"Andrew Cooper" <andrew.cooper3@citrix.com>,
	"Julien Grall" <jgrall@amazon.com>,
	"Ian Jackson" <ian.jackson@eu.citrix.com>,
	"George Dunlap" <george.dunlap@citrix.com>,
	xen-devel@lists.xenproject.org,
	"Volodymyr Babchuk" <Volodymyr_Babchuk@epam.com>,
	"Roger Pau Monné" <roger.pau@citrix.com>
Subject: Re: [PATCH 6/7] xen/guest_access: Consolidate guest access helpers in xen/guest_access.h
Date: Wed, 29 Apr 2020 16:03:47 +0100	[thread overview]
Message-ID: <a5c64ae8-5a32-1616-df34-30efb0dfb8de@xen.org> (raw)
In-Reply-To: <a3e48e70-0fff-c4dc-1e46-4e436e8b84e2@suse.com>

On 29/04/2020 15:54, Jan Beulich wrote:
> On 29.04.2020 16:13, Julien Grall wrote:
>> So can you please have another and explain how the line can be drawn with just two architectures in place.
> 
> There are abstract considerations that can be used to draw the
> line, as well as knowledge of people on architectures Xen doesn't
> run on, but where one can - with such knowledge - extrapolate how
> it would want to be implemented.
 >
> I don't think the question at this point is where to draw the
> line, but whether to have asm-generic/ in the first place.

Well the two come together. You can't add a new directory with no clear 
view how this is going to be used.

At the moment, this would result at best bikeshedding because 
developpers may have a different opinion on how a new architecture would 
be implemented in Xen.

If you have a 3rd architectures then it would be easier to argue the 
header should be added in asm-generic/ or xen/:
    - asm-generic/ should be used if 2 of the architectures are using 
the same interface
    - xen/ should be if the 3 architectures are using the same interface

Cheers,

-- 
Julien Grall