From: Paul Brook <paul@codesourcery.com>
To: qemu-devel@nongnu.org
Cc: C Anthony Risinger <anthony@xtfx.me>
Subject: Re: [Qemu-devel] VirtIO 9p mount_tag (bogus?) limit of 32 bytes
Date: Thu, 16 Feb 2012 20:54:17 +0000 [thread overview]
Message-ID: <201202162054.18209.paul@codesourcery.com> (raw)
In-Reply-To: <CAGAVQTHimKBTkLHMFcwSeNYJqV=y0dvor-D6s+M8UHTmmzHAxQ@mail.gmail.com>
> i see an error message has been added, which is great (i killed a
> couple hours of $%!@ until i noticed the truncated length was *exactly
> 32* bytes; silent truncation), but it would really be great if this
> restriction could be lifted, or at least mitigated by expanding the
> field some.
>
> is config space that precious?
Yes.
> what constrains it (personal curiosity :-)?
Virtio PCI devices map the config space directly onto an ISA IO port range,
along with the virtio control structure. On most systems (in particular
anything PC based) this is a 16-bit address space. i.e. you have
substantually less than 64k of virtio config space for the whole machine, and
potentially only a couple of kbytes for a given PCI bus.
Paul
next prev parent reply other threads:[~2012-02-16 20:54 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-16 12:20 [Qemu-devel] VirtIO 9p mount_tag (bogus?) limit of 32 bytes C Anthony Risinger
2012-02-16 20:54 ` Paul Brook [this message]
2012-02-18 17:38 ` Aneesh Kumar K.V
2012-02-22 3:58 ` C Anthony Risinger
2012-02-23 18:08 ` Aneesh Kumar K.V
2012-03-07 16:29 ` M. Mohan Kumar
-- strict thread matches above, loose matches on Subject: below --
2011-09-22 17:42 Daniel P. Berrange
2011-09-28 11:52 ` Harsh Bora
2011-09-28 15:18 ` Daniel P. Berrange
2011-09-29 15:22 ` Aneesh Kumar K.V
2011-09-29 15:45 ` Daniel P. Berrange
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