From: Juergen Gross <jgross@suse.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
lkml <linux-kernel@vger.kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH] x86: fix {pmd,pud}_{set,clear}_flags()
Date: Mon, 19 Feb 2018 18:41:22 +0100 [thread overview]
Message-ID: <cca49cd2-d59d-07e3-273b-3a45f32fab2c@suse.com> (raw)
In-Reply-To: <5A8B119F02000078001A9412@suse.com>
On 19/02/18 18:04, Jan Beulich wrote:
>>>> On 19.02.18 at 17:23, <jgross@suse.com> wrote:
>> On 19/02/18 15:48, Jan Beulich wrote:
>>> Just like pte_{set,clear}_flags() their PMD and PUD counterparts should
>>> not do any address translation. This was outright wrong under Xen
>>> (causing a dead boot with no useful output on "suitable" systems), and
>>> produced needlessly more complicated code (even if just slightly) when
>>> paravirt was enabled.
>>>
>>> Signed-off-by: Jan Beulich <jbeulich@suse.com>
>>> Cc: stable@vger.kernel.org
>>
>> While the changes look alright I'm really curious which kind of failure
>> you are seeing, especially considering how long those functions haven't
>> been changed (since more than 6 years).
>
> It's the new use of pmd_set_flags() in 2cc42bac1c ("x86-64/Xen:
> eliminate W+X mappings"), and due to the (very odd afaic) identity
> map handling the issue is invisible on most systems/setups.
Aah, okay. This helps.
Reviewed-by: Juergen Gross <jgross@suse.com>
Juergen
next prev parent reply other threads:[~2018-02-19 17:41 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <5A8AF1BB02000078001A91C3@suse.com>
2018-02-19 16:23 ` Juergen Gross
2018-02-19 17:04 ` Jan Beulich
[not found] ` <5A8B119F02000078001A9412@suse.com>
2018-02-19 17:41 ` Juergen Gross [this message]
2018-02-19 14:48 Jan Beulich
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