From mboxrd@z Thu Jan  1 00:00:00 1970
From: Pekka Enberg <penberg@kernel.org>
Subject: Re: KVM_CREATE_VCPU max vcpu ABI
Date: Sat, 07 May 2011 17:48:19 +0300
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References: <BANLkTin6HzjzCkb6cVux0+mkwT8GxwLG1w@mail.gmail.com>
	 <4DC52919.2040100@web.de>
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Cc: Avi Kivity <avi@redhat.com>, KVM General <kvm@vger.kernel.org>,
	Ingo Molnar <mingo@elte.hu>, Asias He <asias.hejun@gmail.com>,
	Cyrill Gorcunov <gorcunov@gmail.com>,
	Sasha Levin <levinsasha928@gmail.com>
To: Jan Kiszka <jan.kiszka@web.de>
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On Sat, 2011-05-07 at 13:12 +0200, Jan Kiszka wrote:
> On 2011-05-07 12:16, Pekka Enberg wrote:
> > Hi!
> > 
> > Documentation/kvm/api.txt says the following:
> > 
> >   4.6 KVM_CREATE_VCPU
> > 
> >   Capability: basic
> >   Architectures: all
> >   Type: vm ioctl
> >   Parameters: vcpu id (apic id on x86)
> >   Returns: vcpu fd on success, -1 on error
> > 
> >   This API adds a vcpu to a virtual machine.  The vcpu id is a small integer
> >   in the range [0, max_vcpus).
> > 
> > However, max_vcpus is not specified and I am unable to find ioctl()
> > which I could use to look it up. Is it specified somewhere? We can, of
> > course, attempt to create as many VCPUs as possible until
> > KVM_CREATE_VCPU returns EINVAL...
> 
> Querying for KVM_CAP_NR_VCPUS returns this number (documented in the kvm
> header). Want to file a patch for adding a hint to the section above?

Done. Thanks Jan!