From: "Jürgen Groß" <jgross@suse.com>
To: Jan Beulich <jbeulich@suse.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Andy Lutomirski <luto@kernel.org>
Cc: lkml <linux-kernel@vger.kernel.org>,
the arch/x86 maintainers <x86@kernel.org>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Subject: Re: [PATCH 1/2] x86/Xen/32: make xen_iret_crit_fixup independent of frame layout
Date: Tue, 19 Nov 2019 14:17:42 +0100 [thread overview]
Message-ID: <f45354ff-4755-1884-444d-007ea46bb847@suse.com> (raw)
In-Reply-To: <32d8713d-25a7-84ab-b74b-aa3e88abce6b@suse.com>
On 11.11.19 15:32, Jan Beulich wrote:
> Now that SS:ESP always get saved by SAVE_ALL, this also needs to be
> accounted for in xen_iret_crit_fixup. Otherwise the old_ax value gets
> interpreted as EFLAGS, and hence VM86 mode appears to be active all
> the time, leading to random "vm86_32: no user_vm86: BAD" log messages
> alongside processes randomly crashing.
>
> Since following the previous model (sitting after SAVE_ALL) would
> further complicate the code _and_ retain the dependency of
> xen_iret_crit_fixup on frame manipulations done by entry_32.S, switch
> things around and do the adjustment ahead of SAVE_ALL.
>
> Fixes: 3c88c692c287 ("x86/stackframe/32: Provide consistent pt_regs")
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Juergen
next prev parent reply other threads:[~2019-11-19 13:17 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-11 14:30 [PATCH 0/2] x86/Xen/32: xen_iret_crit_fixup adjustments Jan Beulich
2019-11-11 14:32 ` [PATCH 1/2] x86/Xen/32: make xen_iret_crit_fixup independent of frame layout Jan Beulich
2019-11-19 13:17 ` Jürgen Groß [this message]
2019-11-19 21:01 ` [tip: x86/urgent] x86/xen/32: Make xen_iret_crit_fixup() " tip-bot2 for Jan Beulich
2019-11-11 14:32 ` [PATCH 2/2] x86/Xen/32: simplify xen_iret_crit_fixup's ring check Jan Beulich
2019-11-19 13:18 ` Jürgen Groß
2019-11-19 21:01 ` [tip: x86/urgent] x86/xen/32: Simplify ring check in xen_iret_crit_fixup() tip-bot2 for Jan Beulich
2019-11-19 12:58 ` Ping: [PATCH 0/2] x86/Xen/32: xen_iret_crit_fixup adjustments Jan Beulich
2019-11-19 17:50 ` Boris Ostrovsky
2019-11-20 2:17 ` Boris Ostrovsky
2019-11-20 2:39 ` Boris Ostrovsky
2019-11-20 7:18 ` [Xen-devel] " Jan Beulich
2019-11-20 7:13 ` Jan Beulich
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