From: Eric Blake <eblake@redhat.com>
To: lma@suse.com,
"pbonzini@redhat.com >> Paolo Bonzini" <pbonzini@redhat.com>
Cc: "qemu-devel@nongnu.org Developers" <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] The issue about parameters(uint64) of a device are treated as signed long int.
Date: Fri, 7 Aug 2015 06:09:06 -0600 [thread overview]
Message-ID: <55C49FE2.4030608@redhat.com> (raw)
In-Reply-To: <55C43A0D.9070000@suse.com>
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On 08/06/2015 10:54 PM, Lin Ma wrote:
> Hi Paolo,
>
> As mentioned in below email, The type of wwn is reported as uint64, But
> in qemu command line, The max valid value for wwn is
> 0x7fffffffffffffff. Obviously, it's treated as int64 there. I'd like to
> know that does the highest bit of _world wide name_ have special
> meaning and must be zero? May I have your thoughts?
You can always pass a negative number to set the highest bit (that's
what libvirt does: when it is sending a uint64 value to qemu via command
line or QMP, it intentionally writes values larger than INT64_MAX by
first casting them to signed and writing the int64_t counterpart
instead). It's a shortcoming in our data parser, and not an actual
prohibition in values you can set. And if you don't like the behavior,
patches are welcome.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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prev parent reply other threads:[~2015-08-07 12:09 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-31 8:28 [Qemu-devel] The issue about parameters(uint64) of a device are treated as signed long int Lin Ma
2015-08-07 4:54 ` Lin Ma
2015-08-07 12:09 ` Eric Blake [this message]
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