linux-kernel - Re: [PATCH 05/13] efi/x86: don't map the entire kernel text RW for mixed mode

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Message-ID: <CAMj1kXEhLjh4NENkzfKmO=eLxEXmgU7MDyJsL51Ctas5XW40Sw@mail.gmail.com>
Date:   Thu, 9 Apr 2020 13:08:17 +0200
From:   Ard Biesheuvel <ardb@...nel.org>
To:     Jiri Slaby <jslaby@...e.cz>
Cc:     Gary Lin <glin@...e.com>, linux-efi <linux-efi@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Anshuman Khandual <anshuman.khandual@....com>,
        Arnd Bergmann <arnd@...db.de>,
        Dan Williams <dan.j.williams@...el.com>,
        Dave Young <dyoung@...hat.com>,
        Saravana Kannan <saravanak@...gle.com>
Subject: Re: [PATCH 05/13] efi/x86: don't map the entire kernel text RW for
 mixed mode

On Thu, 9 Apr 2020 at 12:45, Ard Biesheuvel <ardb@...nel.org> wrote:
>
> On Thu, 9 Apr 2020 at 12:09, Jiri Slaby <jslaby@...e.cz> wrote:
> >
> > On 09. 04. 20, 11:09, Ard Biesheuvel wrote:
> > > On Thu, 9 Apr 2020 at 10:36, Jiri Slaby <jslaby@...e.cz> wrote:
> > >>
> > >> On 09. 04. 20, 10:19, Ard Biesheuvel wrote:
> > >>>>>> $ rpm -qlp ~/Downloads/ovmf-202002-1.1.i586.rpm
> > >>>>>> warning: /home/ardbie01/Downloads/ovmf-202002-1.1.i586.rpm: Header V3
> > >>>>>> RSA/SHA256 Signature, key ID 3dbdc284: NOKEY
> > >>>>>> /usr/share/doc/packages/ovmf
> > >>>>>> /usr/share/doc/packages/ovmf/README
> > >>>>>
> > >>>>> Hmmm, it's weird that OBS doesn't list all derived files.
> > >>>>> Anyway, the ia32 ovmf is available in
> > >>>>> http://download.opensuse.org/tumbleweed/repo/oss/noarch/qemu-ovmf-ia32-202002-1.1.noarch.rpm
> > >>>>
> > >>>> It indeed does:
> > >>>> https://build.opensuse.org/package/binaries/openSUSE:Factory/ovmf/standard
> > >>>>
> > >>>> Note that the ia32 version is noarch, built on i586.
> > >>>>
> > >>>
> > >>> I am not able to reproduce this issue using the linked firmware image
> > >>> and a 5.6 x86_64_defconfig with efivarfs built in.
> > >>
> > >> Yeah, I had to use the distro config too. Not sure what the trigger is.
> > >> Maybe some NUMA configs or something.
> > >>
> > >>> Could anyone share the full log, please, along with the kernel config
> > >>> that was used?
> > >>
> > >> Both uploaded:
> > >> http://decibel.fi.muni.cz/~xslaby/err/
> > >>
> > >
> > > With the same config, I am still not seeing the issue.
> > >
> > >
> > >> Note that I switched the for-me-necessary =m configs to =y. So that it
> > >> is enough to build bzImage, w/o modules...
> > >>
> > >
> > > Could you please try running it again with CONFIG_EFI_PGT_DUMP=y enabled?
> >
> > No problem:
> > http://decibel.fi.muni.cz/~xslaby/err/dmesg2.txt
> >
> > > In the mean time, I will try to install Tumbleweed from scratch. Do
> > > you have any steps I could follow to reproduce your setup?
> >
> > Not really, just installed TW 64-bit and used efi and grub 32 bit.
> >
>
> OK, so you installed using a 64-bit EFI, and then switched to a 32-bit
> one? Or is there a special mixed-mode capable installer?
>
> (The ones I found are x86_64 only)

OK, I have managed to install tumbleweed into a 64-bit VM with 64-bit GRUB.

Could you give any instructions how to convert to 32-bit GRUB please?