linux-kernel - Re: [PATCH 2/4] xen: limit grant v2 interface to the v1 functionality

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <2777c0f8-7555-fbf3-6e18-81cea2fd1a39@oracle.com>
Date:   Tue, 12 Sep 2017 12:05:57 -0400
From:   Boris Ostrovsky <boris.ostrovsky@...cle.com>
To:     Juergen Gross <jgross@...e.com>, linux-kernel@...r.kernel.org,
        xen-devel@...ts.xenproject.org
Subject: Re: [PATCH 2/4] xen: limit grant v2 interface to the v1 functionality

On 09/12/2017 11:50 AM, Juergen Gross wrote:
> On 12/09/17 17:44, Boris Ostrovsky wrote:
>> On 09/08/2017 10:48 AM, Juergen Gross wrote:
>>> As there is currently no user for sub-page grants or transient grants
>>> remove that functionality. This at once makes it possible to switch
>>> from grant v2 to grant v1 without restrictions, as there is no loss of
>>> functionality other than the limited frame number width related to
>>> the switch.
>> But isn't that ABI violation? v2 is expected to support this (XSAs
>> notwithstanding)
> No, I don't think so.
>
> The hypervisor still supports it, but the domU (or dom0) isn't required
> to make use of all the features IMHO. Or are you aware of any backend
> querying the grant version of a frontend and acting in another way if v2
> is detected?

I am not aware of any but that doesn't mean that they don't (or won't)
exist.

-boris