Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: s390 qemu boot failure in -next
To:     Cornelia Huck <cohuck@redhat.com>,
        Vasily Gorbik <gor@linux.ibm.com>
Cc:     Guenter Roeck <linux@roeck-us.net>,
        Martin Schwidefsky <schwidefsky@de.ibm.com>,
        Heiko Carstens <heiko.carstens@de.ibm.com>,
        linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
        qemu-s390x <qemu-s390x@nongnu.org>,
        qemu-devel <qemu-devel@nongnu.org>,
        Thomas Huth <thuth@redhat.com>
References: <20180622194736.GA5794@roeck-us.net>
 <126ac556-0602-b927-58f5-cb5f65a5e0ec@de.ibm.com>
 <88d9afed-f91d-c320-13c8-9a93fc52b700@de.ibm.com>
 <20180625100548.64222dad.cohuck@redhat.com>
 <your-ad-here.call-01529915788-ext-6027@work.hours>
 <20180625104928.6c4cb239.cohuck@redhat.com>
From:   Christian Borntraeger <borntraeger@de.ibm.com>
Openpgp: preference=signencrypt
Autocrypt: addr=borntraeger@de.ibm.com; prefer-encrypt=mutual; keydata=
 xsFNBE6cPPgBEAC2VpALY0UJjGmgAmavkL/iAdqul2/F9ONz42K6NrwmT+SI9CylKHIX+fdf
 J34pLNJDmDVEdeb+brtpwC9JEZOLVE0nb+SR83CsAINJYKG3V1b3Kfs0hydseYKsBYqJTN2j
 CmUXDYq9J7uOyQQ7TNVoQejmpp5ifR4EzwIFfmYDekxRVZDJygD0wL/EzUr8Je3/j548NLyL
 4Uhv6CIPf3TY3/aLVKXdxz/ntbLgMcfZsDoHgDk3lY3r1iwbWwEM2+eYRdSZaR4VD+JRD7p8
 0FBadNwWnBce1fmQp3EklodGi5y7TNZ/CKdJ+jRPAAnw7SINhSd7PhJMruDAJaUlbYaIm23A
 +82g+IGe4z9tRGQ9TAflezVMhT5J3ccu6cpIjjvwDlbxucSmtVi5VtPAMTLmfjYp7VY2Tgr+
 T92v7+V96jAfE3Zy2nq52e8RDdUo/F6faxcumdl+aLhhKLXgrozpoe2nL0Nyc2uqFjkjwXXI
 OBQiaqGeWtxeKJP+O8MIpjyGuHUGzvjNx5S/592TQO3phpT5IFWfMgbu4OreZ9yekDhf7Cvn
 /fkYsiLDz9W6Clihd/xlpm79+jlhm4E3xBPiQOPCZowmHjx57mXVAypOP2Eu+i2nyQrkapaY
 IdisDQfWPdNeHNOiPnPS3+GhVlPcqSJAIWnuO7Ofw1ZVOyg/jwARAQABzTRDaHJpc3RpYW4g
 Qm9ybnRyYWVnZXIgKElCTSkgPGJvcm50cmFlZ2VyQGRlLmlibS5jb20+wsF4BBMBAgAiBQJO
 nDz4AhsDBgsJCAcDAgYVCAIJCgsEFgIDAQIeAQIXgAAKCRARe7yAtaYcfOYVD/9sqc6ZdYKD
 bmDIvc2/1LL0g7OgiA8pHJlYN2WHvIhUoZUIqy8Sw2EFny/nlpPVWfG290JizNS2LZ0mCeGZ
 80yt0EpQNR8tLVzLSSr0GgoY0lwsKhAnx3p3AOrA8WXsPL6prLAu3yJI5D0ym4MJ6KlYVIjU
 ppi4NLWz7ncA2nDwiIqk8PBGxsjdc/W767zOOv7117rwhaGHgrJ2tLxoGWj0uoH3ZVhITP1z
 gqHXYaehPEELDV36WrSKidTarfThCWW0T3y4bH/mjvqi4ji9emp1/pOWs5/fmd4HpKW+44tD
 Yt4rSJRSa8lsXnZaEPaeY3nkbWPcy3vX6qafIey5d8dc8Uyaan39WslnJFNEx8cCqJrC77kI
 vcnl65HaW3y48DezrMDH34t3FsNrSVv5fRQ0mbEed8hbn4jguFAjPt4az1xawSp0YvhzwATJ
 YmZWRMa3LPx/fAxoolq9cNa0UB3D3jmikWktm+Jnp6aPeQ2Db3C0cDyxcOQY/GASYHY3KNra
 z8iwS7vULyq1lVhOXg1EeSm+lXQ1Ciz3ub3AhzE4c0ASqRrIHloVHBmh4favY4DEFN19Xw1p
 76vBu6QjlsJGjvROW3GRKpLGogQTLslbjCdIYyp3AJq2KkoKxqdeQYm0LZXjtAwtRDbDo71C
 FxS7i/qfvWJv8ie7bE9A6Wsjn87BTQROnDz4ARAAmPI1e8xB0k23TsEg8O1sBCTXkV8HSEq7
 JlWz7SWyM8oFkJqYAB7E1GTXV5UZcr9iurCMKGSTrSu3ermLja4+k0w71pLxws859V+3z1jr
 nhB3dGzVZEUhCr3EuN0t8eHSLSMyrlPL5qJ11JelnuhToT6535cLOzeTlECc51bp5Xf6/XSx
 SMQaIU1nDM31R13o98oRPQnvSqOeljc25aflKnVkSfqWSrZmb4b0bcWUFFUKVPfQ5Z6JEcJg
 Hp7qPXHW7+tJTgmI1iM/BIkDwQ8qe3Wz8R6rfupde+T70NiId1M9w5rdo0JJsjKAPePKOSDo
 RX1kseJsTZH88wyJ30WuqEqH9zBxif0WtPQUTjz/YgFbmZ8OkB1i+lrBCVHPdcmvathknAxS
 bXL7j37VmYNyVoXez11zPYm+7LA2rvzP9WxR8bPhJvHLhKGk2kZESiNFzP/E4r4Wo24GT4eh
 YrDo7GBHN82V4O9JxWZtjpxBBl8bH9PvGWBmOXky7/bP6h96jFu9ZYzVgIkBP3UYW+Pb1a+b
 w4A83/5ImPwtBrN324bNUxPPqUWNW0ftiR5b81ms/rOcDC/k/VoN1B+IHkXrcBf742VOLID4
 YP+CB9GXrwuF5KyQ5zEPCAjlOqZoq1fX/xGSsumfM7d6/OR8lvUPmqHfAzW3s9n4lZOW5Jfx
 bbkAEQEAAcLBXwQYAQIACQUCTpw8+AIbDAAKCRARe7yAtaYcfPzbD/9WNGVf60oXezNzSVCL
 hfS36l/zy4iy9H9rUZFmmmlBufWOATjiGAXnn0rr/Jh6Zy9NHuvpe3tyNYZLjB9pHT6mRZX7
 Z1vDxeLgMjTv983TQ2hUSlhRSc6e6kGDJyG1WnGQaqymUllCmeC/p9q5m3IRxQrd0skfdN1V
 AMttRwvipmnMduy5SdNayY2YbhWLQ2wS3XHJ39a7D7SQz+gUQfXgE3pf3FlwbwZhRtVR3z5u
 aKjxqjybS3Ojimx4NkWjidwOaUVZTqEecBV+QCzi2oDr9+XtEs0m5YGI4v+Y/kHocNBP0myd
 pF3OoXvcWdTb5atk+OKcc8t4TviKy1WCNujC+yBSq3OM8gbmk6NwCwqhHQzXCibMlVF9hq5a
 FiJb8p4QKSVyLhM8EM3HtiFqFJSV7F+h+2W0kDyzBGyE0D8z3T+L3MOj3JJJkfCwbEbTpk4f
 n8zMboekuNruDw1OADRMPlhoWb+g6exBWx/YN4AY9LbE2KuaScONqph5/HvJDsUldcRN3a5V
 RGIN40QWFVlZvkKIEkzlzqpAyGaRLhXJPv/6tpoQaCQQoSAc5Z9kM/wEd9e2zMeojcWjUXgg
 oWj8A/wY4UXExGBu+UCzzP/6sQRpBiPFgmqPTytrDo/gsUGqjOudLiHQcMU+uunULYQxVghC
 syiRa+UVlsKmx1hsEg==
Date:   Mon, 25 Jun 2018 14:26:45 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101
 Thunderbird/52.7.0
MIME-Version: 1.0
In-Reply-To: <20180625104928.6c4cb239.cohuck@redhat.com>
Content-Language: en-US
Message-Id: <76740f8f-ef4c-9d11-dae1-192beebff4d8@de.ibm.com>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk


On 06/25/2018 10:49 AM, Cornelia Huck wrote:
> On Mon, 25 Jun 2018 10:36:33 +0200
> Vasily Gorbik <gor@linux.ibm.com> wrote:
> 
>> This change has been done on purpose. Uncompressed image is not going
>> to be bootable any more. In future the decompressor phase would get
>> more function (early memory detection as an example) and there is no
>> chance to duplicate that code in uncompressed image as well (to keep it
>> bootable on its own). The patch series commit messages contain more
>> technical details.
>>
>> For qemu either bzImage or arch/s390/boot/compressed/vmlinux should be
>> used, which are bootable images.
>>
>> But that's really confusing that uncompressed vmlinux is still kind
>> of booting. May be we should discuss how to avoid this confusion
>> (may be change uncompressed image enty point to a function doing
>> disabled wait with badb007 or smth) and how to encourage people to use
>> arch/s390/boot/compressed/vmlinux instead.
> 
> So, the intention is that you can't boot the uncompressed image
> anywhere? (Was it possible before, e.g. when punching the image under
> z/VM?)

The uncompressed image (the vmlinux file) was never bootable in LPAR or z/VM.
It was just a "nice hack" that QEMU was able to do so. (even qemu on x86 can not
boot the pure vmlinux file as far as I know).

I talked to Vasily and the vmlinux file in the linux source path is just an 
intermediate file. Future changes will happen that will make that ELF file
unsuitable for direct boot anyway (e.g. think about potential ASLR or Kasan
changes).

 If yes, it would make sense to explicitly fence it. But I'm
> worried that it would break previously working setups (did we document
> the purpose of the images anywhere?)
> 


I think by referring to arch/s390/boot/compressed/vmlinux things are probably
good enough. That will still load from 0x10000.

We might still "change" the way that we add the parameters (e.g.
make that not depend on the load address), but looking forward this might
become less important for the "intermediate vmlnux file".