From mboxrd@z Thu Jan  1 00:00:00 1970
From: Cornelia Huck <cohuck@redhat.com>
Subject: Re: [PATCH RFC v3 7/9] KVM: add kvm_free_vcpus and
 kvm_arch_free_vcpus
Date: Tue, 29 Aug 2017 15:00:44 +0200
Message-ID: <20170829150044.554b5288.cohuck@redhat.com>
References: <20170821203530.9266-1-rkrcmar@redhat.com>
        <20170821203530.9266-8-rkrcmar@redhat.com>
        <45e07499-e60c-5289-f439-9c51f59866ec@redhat.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Cc: Radim =?UTF-8?B?S3LEjW3DocWZ?= <rkrcmar@redhat.com>,
        linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        linux-mips@linux-mips.org, kvm-ppc@vger.kernel.org,
        linux-s390@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        Paolo Bonzini <pbonzini@redhat.com>,
        Christoffer Dall <cdall@linaro.org>,
        Marc Zyngier <marc.zyngier@arm.com>,
        Christian Borntraeger <borntraeger@de.ibm.com>,
        James Hogan <james.hogan@imgtec.com>,
        Paul Mackerras <paulus@ozlabs.org>,
        Alexander Graf <agraf@suse.com>
To: David Hildenbrand <david@redhat.com>
Return-path: <linux-kernel-owner@vger.kernel.org>
In-Reply-To: <45e07499-e60c-5289-f439-9c51f59866ec@redhat.com>
Sender: linux-kernel-owner@vger.kernel.org
List-Id: kvm.vger.kernel.org

On Tue, 22 Aug 2017 16:18:59 +0200
David Hildenbrand <david@redhat.com> wrote:

> > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> > index 33a15e176927..0d2d8b0c785c 100644
> > --- a/virt/kvm/kvm_main.c
> > +++ b/virt/kvm/kvm_main.c
> > @@ -750,6 +750,23 @@ static void kvm_destroy_devices(struct kvm *kvm)
> >  	}
> >  }
> >  
> > +void kvm_free_vcpus(struct kvm *kvm)
> > +{
> > +	int i;
> > +
> > +	kvm_arch_free_vcpus(kvm);  
> 
> I wonder if it would be possible to get rid of kvm_arch_free_vcpus(kvm)
> completely and simply call
> 
> kvm_for_each_vcpu(i, vcpu, kvm)
> 	kvm_arch_vcpu_free(vcpu);
> 
> at that point.
> 
> Would certainly require some refactoring, and I am not sure if we could
> modify the special mmu handling for x86 ("Unpin any mmu pages first.").
> But if in doubt, that part could be moved to kvm_arch_destroy_vm(), just
> before calling kvm_free_vcpus().

Nod, that crossed my mind as well. Would avoid adding lots of
kvm_arch_free_vcpus() that do the same thing for many archs.