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

[Juergen Gross]

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@xxxxxxxx>
> 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
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