linux-kernel - Re: [Bug Report] Linux v6.15-rc7 boot failure on Xen-4.17

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Message-ID: <227db775-f4ce-4dd3-ba14-30232ab3ab6f@suse.com>
Date: Wed, 28 May 2025 07:11:44 +0200
From: Jürgen Groß <jgross@...e.com>
To: Andrew Cooper <andrew.cooper3@...rix.com>, Xin Li <xin@...or.com>
Cc: Gupta Pawan <pawan.kumar.gupta@...ux.intel.com>,
 linux-kernel@...r.kernel.org, x86@...nel.org,
 Zijlstra Peter <peterz@...radead.org>,
 Hansen Dave <dave.hansen@...ux.intel.com>, alexandre.chartre@...cle.com,
 Zhang Tao1 <tao1.zhang@...el.com>
Subject: Re: [Bug Report] Linux v6.15-rc7 boot failure on Xen-4.17

On 27.05.25 21:29, Andrew Cooper wrote:
> On 27/05/2025 8:21 pm, Xin Li wrote:
>>> On May 27, 2025, at 11:36 AM, Jürgen Groß <jgross@...e.com> wrote:
>>>
>>> On 27.05.25 19:54, Xin Li wrote:
>>>> On 5/27/2025 10:46 AM, Pawan Gupta wrote:
>>>>>> Attached is the serial console log and my kernel config.
>>>>> Serial logs aren't telling much. I do not have a Xen setup to test, without
>>>>> Xen the config that you provided is booting a KVM guest just fine.
>>>> Yeah, as I replied to Juergen, the same kernel binary boots fine as
>>>> "native".
>>>> Unfortunately when booting as dom0 on Xen, it keeps rebooting w/o
>>>> helpful log.
>>> What about booting Xen on bare metal, i.e. no KVM being involved?
>> The same exact problem happens on Intel Simics.  And I got to see it’s a NX page fault in dom0 kernel during apply alternatives.
> 
> In which case it's likely that there's an opencoded PTE update, rather
> than using the hooks (which are suitably paravirt'd).

I'd suspect a bug when NOT using 2M pages for execmem.

I'll have a look.


Juergen

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