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Date: Wed, 8 Dec 2010 15:04:08 +0000
Message-ID: <AANLkTiny__f-b4jZ2a7_uqcm_mY9pmRzC8c+nsV=Bjac@mail.gmail.com>
Subject: Re: [Qemu-devel] Booting from VirtIO disk
From: Stefan Hajnoczi <stefanha@gmail.com>
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To: =?UTF-8?B?4KSF4KSo4KWB4KSc?= <anuj01@gmail.com>
Cc: qemu-devel <qemu-devel@nongnu.org>

2010/12/8 =E0=A4=85=E0=A4=A8=E0=A5=81=E0=A4=9C <anuj01@gmail.com>:
> Hi
>
> thanks for your quick response. Please see the comments inline.
>
> 2010/12/8 Stefan Hajnoczi <stefanha@gmail.com>:
>> 2010/12/8 =E0=A4=85=E0=A4=A8=E0=A5=81=E0=A4=9C <anuj01@gmail.com>:
>>> Hi list
>>>
>>> I got confused after observing that there is no support for VirtIO
>>> block devices in Seabios supplied with Qemu-0.12.3. But still it can
>>> accept a VirtIO disk as a bootable device and perfectly boots from it.
>>> Then How it's done?
>>>
>>> But I can see the VirtIO block device code in Seabios source supplied
>>> with Qemu-0.13.0.
>>
>> Before SeaBIOS had native support for virtio-blk there was the extboot
>> option ROM which could boot from virtio-blk devices by reading a
>> special I/O port (it does not speak virtio-blk, see qemu-kvm.git
>> hw/extboot.c).
>
> I couldn't find this file in qemu versions 0.12.3 and 0.13.0. And my
> same doubt is also for SCSI disks.

Please keep qemu-devel@nongnu.org CCed so others can follow the
conversation and help too.

You probably looked at QEMU source code (from qemu.git).  The extboot
code is in qemu-kvm.git (which is shipped as the "kvm" or "qemu-kvm"
package on distros).  Are you sure you tested virtio-blk boot in
qemu.git-based code?

Stefan