From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jan Kiszka <jan.kiszka@web.de>
Subject: Re: KVM_CREATE_VCPU max vcpu ABI
Date: Sat, 07 May 2011 13:12:25 +0200
Message-ID: <4DC52919.2040100@web.de>
References: <BANLkTin6HzjzCkb6cVux0+mkwT8GxwLG1w@mail.gmail.com>
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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: Pekka Enberg <penberg@kernel.org>
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On 2011-05-07 12:16, Pekka Enberg wrote:
> Hi!
>=20
> Documentation/kvm/api.txt says the following:
>=20
>   4.6 KVM_CREATE_VCPU
>=20
>   Capability: basic
>   Architectures: all
>   Type: vm ioctl
>   Parameters: vcpu id (apic id on x86)
>   Returns: vcpu fd on success, -1 on error
>=20
>   This API adds a vcpu to a virtual machine.  The vcpu id is a small in=
teger
>   in the range [0, max_vcpus).
>=20
> 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?

Jan


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