Groups > linux.kernel > #1420951

Re: [PATCH 1/3] KVM: introduce kvm->created_vcpus

From	Cornelia Huck <cornelia.huck@de.ibm.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 1/3] KVM: introduce kvm->created_vcpus
Date	2016-06-13 16:50 +0200
Message-ID	<rJBlE-7AX-35@gated-at.bofh.it> (permalink)
References	<rJA6d-6PL-13@gated-at.bofh.it> <rJA6e-6PL-19@gated-at.bofh.it>
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On Mon, 13 Jun 2016 15:25:30 +0200
Paolo Bonzini <pbonzini@redhat.com> wrote:

> The race between creating the irqchip and the first VCPU is
> currently fixed by checking the presence of an irqchip before
> updating kvm->online_vcpus, and undoing the whole VCPU creation
> if someone created the irqchip in the meanwhile.
> 
> Instead, introduce a new field in struct kvm that will count VCPUs
> under a mutex, without the atomic access and memory ordering that we
> need elsewhere to protect the vcpus array.  This also plugs the race
> and is more easily applicable in all similar circumstances.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  include/linux/kvm_host.h |  8 ++++++++
>  virt/kvm/kvm_main.c      | 23 +++++++++++++++++------
>  2 files changed, 25 insertions(+), 6 deletions(-)

Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>

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[PATCH 1/3] KVM: introduce kvm->created_vcpus Paolo Bonzini <pbonzini@redhat.com> - 2016-06-13 15:30 +0200
  Re: [PATCH 1/3] KVM: introduce kvm->created_vcpus Cornelia Huck <cornelia.huck@de.ibm.com> - 2016-06-13 16:50 +0200

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