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From: "Daniel P. Berrangé" <berrange@redhat.com>
To: Andrea Bolognani <abologna@redhat.com>
Cc: Eric Blake <eblake@redhat.com>, Kevin Wolf <kwolf@redhat.com>,
	qemu-block@nongnu.org, "Michael S. Tsirkin" <mst@redhat.com>,
	qemu-devel@nongnu.org, armbru@redhat.com,
	"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
	"Richard W.M. Jones" <rjones@redhat.com>,
	stefanha@redhat.com, Max Reitz <mreitz@redhat.com>
Subject: Re: [Qemu-devel] storing machine data in qcow images?
Date: Thu, 7 Jun 2018 11:22:57 +0100	[thread overview]
Message-ID: <20180607102257.GH28827@redhat.com> (raw)
In-Reply-To: <f3914a591a46c9d489f2fa1ad2ac4fd0c5a9e5b6.camel@redhat.com>

On Thu, Jun 07, 2018 at 12:02:29PM +0200, Andrea Bolognani wrote:
> On Wed, 2018-06-06 at 17:32 +0100, Daniel P. Berrangé wrote:
> > On Wed, Jun 06, 2018 at 10:36:20AM -0500, Eric Blake wrote:
> > > But for the new config to be useful, you have to modify at least one tool in
> > > the path.  At which point, it is just as easy to say: "libvirt is now smart
> > > enough to read the config file out of a .qcow2 to know that it should prefer
> > > a q35 machine" as it is to say "libvirt is now smart enough to treat a .tar
> > > file containing .qcow2 and a config file that states that it should prefer a
> > > q35 machine", and either approach requires just a single file for the user
> > > to download.
> > 
> > Just to be clear, libvirt isn't going to do either of those things.
> > 
> > Whether there is metadata stuffed inside qcow2, or in a metdata file
> > inside a tar file, libvirt is not going to look inside either of them.
> > The XML is the only place libvirt deals with the hardware config.
> > 
> > Extracting machine type is always going to be a job for the layer above
> > such as OpenStack/OVirt/Virt-manager/etc. They will then decide whether
> > or not they want to honour that info, and if so, put it into the XML
> > they give to libvirt.
> > 
> > As mentioned elsewhere, IMHO, it is more friendly to those tools
> > to use pre-existing formats, eg TAR and XML/JSON, for which
> > their respective programming langauges already have APIs/parsers.
> 
> Something that I haven't seen mentioned in the thread - and this
> looks like as good a point as any to jump in - is that for q35
> guests using EFI as well as aarch64 guests the "one click import"
> experience requires not only hints about the machine (and firmware!)
> type, but also a copy of the EFI variable store:
> 
>   $ virt-builder fedora-27 --arch aarch64 --notes
>   Fedora® 27 Server (aarch64)
> 
>   [...]
> 
>   You will need to use the associated UEFI NVRAM variables file:
>     http://libguestfs.org/download/builder/fedora-27-aarch64-nvram.xz
> 
> While hints might be considered a reasonable fit for qcow2, I think
> it's pretty hard to argue for embedding the NVRAM file in there,
> which to me signals quite clearly that an archive containing the
> disk image(s) *and* the configuration hints *and* other ancillary
> files such as the NVRAM is the only way to build a solution that's
> not dead on arrival.

On a similar theme, I can imagine users wanting to provide a TPM
data blob too, and for AMD SEV we'd need to be able to provide a
DH key, and session blob too IIUC.

Regards,
Daniel
-- 
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  reply	other threads:[~2018-06-07 10:23 UTC|newest]

Thread overview: 157+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-18 15:30 [Qemu-devel] storing machine data in qcow images? Michael S. Tsirkin
2018-05-18 16:49 ` Eduardo Habkost
2018-05-18 17:09 ` Daniel P. Berrangé
2018-05-18 17:41   ` Eduardo Habkost
2018-05-19  6:05     ` Markus Armbruster
2018-05-21 18:29       ` Eduardo Habkost
2018-05-21 18:44         ` Daniel P. Berrangé
2018-05-21 19:01           ` Eduardo Habkost
2018-05-23 11:19             ` Markus Armbruster
2018-05-23 12:13               ` Eduardo Habkost
2018-05-23 16:35                 ` Markus Armbruster
2018-05-29 14:06                   ` Dr. David Alan Gilbert
2018-06-05 21:58                   ` Michal Suchánek
2018-05-21 20:18     ` Daniel P. Berrangé
2018-05-21 20:33       ` Eduardo Habkost
2018-05-24  9:58         ` Kashyap Chamarthy
2018-05-22  7:35   ` Gerd Hoffmann
2018-05-22 10:53     ` Eduardo Habkost
2018-05-22 14:19     ` Michael S. Tsirkin
2018-05-22 15:02       ` Kevin Wolf
2018-05-22 15:14         ` Eduardo Habkost
2018-05-23  2:12         ` Fam Zheng
2018-05-23  9:16           ` Kevin Wolf
2018-05-23 14:46             ` Michael S. Tsirkin
2018-05-24 11:17   ` Richard W.M. Jones
2018-05-29 14:03     ` Dr. David Alan Gilbert
2018-05-29 14:14       ` Eduardo Habkost
2018-05-29 14:51         ` Richard W.M. Jones
2018-05-29 15:31         ` Dr. David Alan Gilbert
2018-05-22  8:50 ` Philipp Hahn
2018-05-24 11:32 ` Richard W.M. Jones
2018-05-24 14:56   ` Michael S. Tsirkin
2018-05-24 15:08     ` Kevin Wolf
2018-05-24 15:19       ` Michael S. Tsirkin
2018-05-24 15:20       ` Richard W.M. Jones
2018-05-24 16:25         ` Markus Armbruster
2018-05-28 18:10   ` Max Reitz
2018-05-28 18:30     ` Richard W.M. Jones
2018-05-28 18:38       ` Kevin Wolf
2018-05-28 18:44         ` Max Reitz
2018-05-28 19:09           ` Kevin Wolf
2018-05-29  9:23             ` Max Reitz
2018-05-29 10:14               ` Kevin Wolf
2018-05-29 13:16                 ` Eduardo Habkost
2018-05-28 21:20         ` Richard W.M. Jones
2018-05-28 21:25           ` Richard W.M. Jones
2018-05-29  6:44             ` Kevin Wolf
2018-05-29 10:14               ` Max Reitz
2018-06-05  9:21                 ` Dr. David Alan Gilbert
2018-06-05 19:03                   ` Eduardo Habkost
2018-06-05 19:47                     ` Michael S. Tsirkin
2018-06-05 19:54                       ` [Qemu-devel] [Qemu-block] " Eric Blake
2018-06-05 19:58                         ` Richard W.M. Jones
2018-06-05 20:09                           ` Eric Blake
2018-06-05 20:28                             ` Michael S. Tsirkin
2018-06-05 20:46                               ` Eric Blake
2018-06-05 21:26                                 ` Michael S. Tsirkin
2018-06-06  8:07                               ` Dr. David Alan Gilbert
2018-06-06  6:23                           ` Gerd Hoffmann
2018-06-05 20:06                         ` Michael S. Tsirkin
2018-06-06  6:26                     ` [Qemu-devel] " Gerd Hoffmann
2018-06-06  9:44                     ` Dr. David Alan Gilbert
2018-06-06 13:35                       ` Eduardo Habkost
2018-06-06 11:02                   ` Max Reitz
2018-06-06 11:14                     ` Dr. David Alan Gilbert
2018-06-06 11:26                       ` Max Reitz
2018-06-06 12:00                         ` Dr. David Alan Gilbert
2018-06-06 12:59                           ` Max Reitz
2018-06-06 14:31                             ` Dr. David Alan Gilbert
2018-06-06 14:37                               ` Daniel P. Berrangé
2018-06-06 14:42                                 ` Dr. David Alan Gilbert
2018-06-06 14:51                               ` Max Reitz
2018-06-06 15:05                                 ` Dr. David Alan Gilbert
2018-06-06 15:36                                   ` Eric Blake
2018-06-06 16:11                                     ` Michal Suchánek
2018-06-06 16:37                                       ` Eric Blake
2018-06-06 16:32                                     ` Daniel P. Berrangé
2018-06-06 16:36                                       ` Dr. David Alan Gilbert
2018-06-07 10:02                                       ` Andrea Bolognani
2018-06-07 10:22                                         ` Daniel P. Berrangé [this message]
2018-06-07 11:17                                           ` Andrea Bolognani
2018-06-07 12:38                                             ` Daniel P. Berrangé
2018-06-07 13:49                                               ` Dr. David Alan Gilbert
2018-06-07 14:06                                                 ` Andrea Bolognani
2018-06-07 14:45                                                   ` Dr. David Alan Gilbert
2018-06-07 14:56                                                     ` Andrea Bolognani
2018-06-07 15:25                                                       ` Dr. David Alan Gilbert
2018-06-07 20:38                                                         ` Gerd Hoffmann
2018-06-07 10:32                                         ` Richard W.M. Jones
2018-06-07 10:35                                           ` Dr. David Alan Gilbert
2018-06-07 10:36                                           ` Daniel P. Berrangé
2018-06-07 10:54                                             ` Andrea Bolognani
2018-06-07 19:24                                               ` Laszlo Ersek
2018-06-08  8:21                                                 ` Dr. David Alan Gilbert
2018-06-08  8:41                                                   ` Daniel P. Berrangé
2018-06-08  8:53                                                     ` Dr. David Alan Gilbert
2018-06-07 21:19                                               ` Michael S. Tsirkin
2018-06-07 21:18                                             ` Michael S. Tsirkin
2018-06-07 10:51                                           ` Andrea Bolognani
2018-06-07 19:38                                             ` Laszlo Ersek
2018-06-06 17:49                                   ` Max Reitz
2018-06-06 15:09                                 ` Michael S. Tsirkin
2018-06-06 17:06                                   ` Max Reitz
2018-06-07 21:43                                     ` Michael S. Tsirkin
2018-06-09 21:34                                       ` Max Reitz
2018-06-11  2:06                                         ` Michael S. Tsirkin
2018-06-11  8:16                                           ` Michal Suchánek
2018-06-06 11:42                       ` Richard W.M. Jones
2018-06-06 11:48                         ` Daniel P. Berrangé
2018-06-06 11:53                           ` Max Reitz
2018-06-06 12:03                           ` Dr. David Alan Gilbert
2018-06-06 13:15                             ` Max Reitz
2018-06-06 12:29                           ` Richard W.M. Jones
2018-06-06 11:22                     ` [Qemu-devel] [Qemu-block] " Peter Krempa
2018-06-06 10:32                 ` [Qemu-devel] " Michal Suchánek
2018-06-06 11:02                   ` Max Reitz
2018-06-06 11:19                     ` Michal Suchánek
2018-06-06 11:32                       ` Max Reitz
2018-06-06 11:37                         ` Dr. David Alan Gilbert
2018-06-06 11:44                           ` Max Reitz
2018-06-06 12:16                             ` Dr. David Alan Gilbert
2018-06-06 13:22                               ` Max Reitz
2018-06-06 14:02                                 ` Dr. David Alan Gilbert
2018-06-06 14:33                                   ` Max Reitz
2018-06-06 14:41                                     ` Dr. David Alan Gilbert
2018-06-06 14:55                                       ` Max Reitz
2018-06-06 15:25                                         ` Michal Suchánek
2018-06-06 18:02                                           ` Max Reitz
2018-06-06 18:33                                             ` Michal Suchánek
2018-06-06 18:36                                               ` Eduardo Habkost
2018-06-07 18:27                                                 ` [Qemu-devel] [Qemu-block] " Kashyap Chamarthy
2018-06-06 13:42                             ` [Qemu-devel] " Eduardo Habkost
2018-06-06 14:55                               ` Michael S. Tsirkin
2018-06-06 14:57                                 ` Max Reitz
2018-06-11 14:10                                 ` Kevin Wolf
2018-06-06 14:46                             ` Michael S. Tsirkin
2018-06-06 15:04                               ` Max Reitz
2018-06-06 11:43                         ` Michal Suchánek
2018-06-06 11:52                           ` Max Reitz
2018-06-06 12:13                             ` Michal Suchánek
2018-06-06 13:14                               ` Max Reitz
2018-06-06 13:45                                 ` Michal Suchánek
2018-06-06 13:50                                   ` Daniel P. Berrangé
2018-06-06 14:14                                     ` Eduardo Habkost
2018-06-06 14:21                                       ` Max Reitz
2018-06-06 14:24                                       ` Daniel P. Berrangé
2018-06-06 14:17                                   ` Max Reitz
2018-06-06 16:10                                     ` Eduardo Habkost
2018-06-06 18:09                                       ` Max Reitz
2018-06-11  8:44                         ` Richard W.M. Jones
2018-06-06 11:40                     ` Richard W.M. Jones
2018-06-06 14:31                       ` Michael S. Tsirkin
2018-06-06 14:43                     ` Michael S. Tsirkin
2018-06-06 14:57                       ` Eric Blake
2018-06-06 20:39                         ` Eric Blake
2018-06-06 21:01                           ` Gerd Hoffmann
2018-06-06 15:02                       ` Max Reitz

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