linux-kernel - Re: [Xen-devel] Ping: [PATCH 0/2] x86/Xen/32: xen_iret_crit

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Message-ID: <c5988a7d-4cc0-390d-92a3-98e00038c3ea@suse.com>
Date:   Wed, 20 Nov 2019 08:13:08 +0100
From:   Jan Beulich <jbeulich@...e.com>
To:     Boris Ostrovsky <boris.ostrovsky@...cle.com>
Cc:     Juergen Gross <jgross@...e.com>, Andy Lutomirski <luto@...nel.org>,
        the arch/x86 maintainers <x86@...nel.org>,
        "xen-devel@...ts.xenproject.org" <xen-devel@...ts.xenproject.org>,
        lkml <linux-kernel@...r.kernel.org>
Subject: Re: [Xen-devel] Ping: [PATCH 0/2] x86/Xen/32: xen_iret_crit_fixup
 adjustments

On 19.11.2019 18:50, Boris Ostrovsky wrote:
> On 11/19/19 7:58 AM, Jan Beulich wrote:
>> On 11.11.2019 15:30, Jan Beulich wrote:
>>> The first patch here fixes another regression from 3c88c692c287
>>> ("x86/stackframe/32: Provide consistent pt_regs"), besides the
>>> one already addressed by
>>> https://lists.xenproject.org/archives/html/xen-devel/2019-10/msg01988.html.
>>> The second patch is a minimal bit of cleanup on top.
>>>
>>> 1: make xen_iret_crit_fixup independent of frame layout
>>> 2: simplify xen_iret_crit_fixup's ring check
>> Seeing that the other regression fix has been taken into -tip,
>> what is the situation here? Should 5.4 really ship with this
>> still unfixed?
> 
> 
> I am still unable to boot a 32-bit guest with those patches, crashing in
> int3_exception_notify with regs->sp zero.
> 
> When I revert to 3c88c692c287 the guest actually boots so my (?) problem
> was introduced somewhere in-between.

In order to even get as far as the patches here taking effect
you first need "x86/stackframe/32: repair 32-bit Xen PV" (which
is what "the other regression fix" in my ping refers to).

Jan