xen-devel.lists.xenproject.org archive mirror
 help / color / mirror / Atom feed
From: Ian Campbell <ian.campbell@citrix.com>
To: Steven Haigh <netwiz@crc.id.au>,
	xen-devel <xen-devel@lists.xenproject.org>
Cc: Anthony Perard <anthony.perard@citrix.com>,
	Stefano Stabellini <Stefano.Stabellini@eu.citrix.com>
Subject: Re: [BUG?] qemuu only built with i386-softmmu
Date: Fri, 5 Feb 2016 09:51:13 +0000	[thread overview]
Message-ID: <1454665873.8672.38.camel@citrix.com> (raw)
In-Reply-To: <56B3BE05.9000208@crc.id.au>

On Fri, 2016-02-05 at 08:09 +1100, Steven Haigh wrote:
> In building my Xen 4.6.0 packages, I disable qemu-traditional and ONLY
> build qemu-upstream - however as the value for i386-softmmu is not based
> on variables, I'm not sure this makes a difference.

QEMU in a Xen system only provides device model (DM) emulation and not any
CPU instruction emulation, so the nominal arch doesn't actually matter and
Xen build's i386 everywhere as a basically arbitrary choice.

It happens that the Xen DM part of QEMU is quite closely tied to the x86
scaffolding for various historical reasons, so we end up using qemu-system-
i386 even e.g. on ARM!

This comes up a lot, So I've also pasted the two paras above into a new
section in http://wiki.xenproject.org/wiki/QEMU_Upstream . If anyone thinks
the above is inaccurate then please edit the wiki (and post here too if you
like).

On thing I was sure on (so didn't write) is whether the second paragraph
could have an extra sentence:

    If you are using a distro supplied QEMU then the qemu-system-x86_64
    could also be used, but it makes no practical difference to the
    functionality of the system.

I wasn't sure if that was true (I suspect it is) and in any case I think
various bits of libxl etc will look for qemu-system-i386 in various paths
so a user would need to try reasonably hard to do so by giving an explicit
path and there is no real reason to do so maybe better not to muddy the
waters?

Ian.

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel

  reply	other threads:[~2016-02-05  9:51 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-04 21:09 [BUG?] qemuu only built with i386-softmmu Steven Haigh
2016-02-05  9:51 ` Ian Campbell [this message]
2016-02-05  9:57   ` Steven Haigh
2016-02-05 10:07     ` Ian Campbell
2016-02-09 15:49       ` Stefano Stabellini
2016-02-09 16:01         ` Ian Campbell

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1454665873.8672.38.camel@citrix.com \
    --to=ian.campbell@citrix.com \
    --cc=Stefano.Stabellini@eu.citrix.com \
    --cc=anthony.perard@citrix.com \
    --cc=netwiz@crc.id.au \
    --cc=xen-devel@lists.xenproject.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).