Re: [REGRESSION][x86] Commit f5b2831d65 cause boot failure in VMware ESXi 5.1 guest

[Qu Wenruo <quwenruo@cn.fujitsu.com>]

-------- Original Message --------
Subject: Re: [REGRESSION][x86] Commit f5b2831d65 cause boot failure in 
VMware ESXi 5.1 guest
From: Juergen Gross <jgross@suse.com>
To: Qu Wenruo <quwenruo@cn.fujitsu.com>
Date: 2014年12月27日 21:51
> On 12/26/2014 02:57 AM, Qu Wenruo wrote:
>> Hi all,
>>
>> When testing v3.19-rc1 kernel(in fact, try to test), the kernel itself
>> fail to boot on VMware ESXi 5.1 guest.
>> The boot failure is quite easy to describe, only one line is output:
>> "Probing EDD (edd=off to disable)...ok"
>>
>> No other output(including warning/bug_on/backtrace or whatever) and the
>> guest just hangs.
>> It's OK on v3.18, so it's a regression.
>>
>> Bisect points to the following commit:
>> commit f5b2831d654167d77da8afbef4d2584897b12d0c
>> Author: Juergen Gross <jgross@suse.com>
>> Date:   Mon Nov 3 14:02:02 2014 +0100
>>
>>      x86: Respect PAT bit when copying pte values between large and
>> normal pages
>>
>>      The PAT bit in the ptes is not moved to the correct position when
>>      copying page protection attributes between entries of different 
>> sized
>>      pages. Translate the ptes according to their page size.
>>
>>
>> I have also created the kernel BZ report:
>> https://bugzilla.kernel.org/show_bug.cgi?id=90321
>>
>> Hopes this can be resolved in next rc.
>
> As the same issue has been reported with VMWare workstation which was
> related to an error in the PAT MSR emulation of VMWare, I guess this
> will be the same problem. I've already sent a patch.
>
> You should be able to boot with the "nopat" kernel option.
>
>
> Juergen
Thanks for the explanation. Again the closed source blob to blame.

Anyway, the nopat option works.

Great thanks
Qu