From: Julien Grall <julien@xen.org>
To: Jan Beulich <jbeulich@suse.com>,
Stefano Stabellini <sstabellini@kernel.org>
Cc: "Wei Liu" <wl@xen.org>,
"Andrew Cooper" <andrew.cooper3@citrix.com>,
"Ian Jackson" <ian.jackson@eu.citrix.com>,
"George Dunlap" <george.dunlap@citrix.com>,
"Bertrand Marquis" <Bertrand.Marquis@arm.com>,
Xen-devel <xen-devel@lists.xenproject.org>, nd <nd@arm.com>,
"Volodymyr Babchuk" <Volodymyr_Babchuk@epam.com>,
"Roger Pau Monné" <roger.pau@citrix.com>
Subject: Re: [PATCH v2] xen/arm: Convert runstate address during hypcall
Date: Fri, 31 Jul 2020 11:12:45 +0100 [thread overview]
Message-ID: <73c8ade5-36a3-cc13-80b6-bda89e175cbb@xen.org> (raw)
In-Reply-To: <1a8bbcc7-9d0c-9669-db7b-e837af279027@suse.com>
Hi Jan,
On 31/07/2020 07:39, Jan Beulich wrote:
> We're fixing other issues without breaking the ABI. Where's the
> problem of backporting the kernel side change (which I anticipate
> to not be overly involved)?
This means you can't take advantage of the runstage on existing Linux
without any modification.
> If the plan remains to be to make an ABI breaking change,
For a theoritical PoV, this is a ABI breakage. However, I fail to see
how the restrictions added would affect OSes at least on Arm.
In particular, you can't change the VA -> PA on Arm without going
through an invalid mapping. So I wouldn't expect this to happen for the
runstate.
The only part that *may* be an issue is if the guest is registering the
runstate with an initially invalid VA. Although, I have yet to see that
in practice. Maybe you know?
> then I
> think this will need an explicit vote.
I was under the impression that the two Arm maintainers (Stefano and I)
already agreed with the approach here. Therefore, given the ABI breakage
is only affecting Arm, why would we need a vote?
Cheers,
--
Julien Grall
next prev parent reply other threads:[~2020-07-31 10:13 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-28 15:52 [PATCH v2] xen/arm: Convert runstate address during hypcall Bertrand Marquis
2020-07-28 19:04 ` Stefano Stabellini
2020-07-29 6:47 ` Bertrand Marquis
2020-07-28 19:54 ` Jan Beulich
2020-07-29 7:08 ` Bertrand Marquis
2020-07-29 18:41 ` Jan Beulich
2020-07-30 1:30 ` Stefano Stabellini
2020-07-31 6:39 ` Jan Beulich
2020-07-31 10:12 ` Julien Grall [this message]
2020-07-31 10:18 ` Jan Beulich
2020-07-31 14:36 ` Bertrand Marquis
2020-07-31 23:03 ` Stefano Stabellini
2020-08-14 9:25 ` Bertrand Marquis
2020-08-20 10:23 ` Julien Grall
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