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Date:   Wed, 15 Jun 2022 11:59:42 +0200
From:   Claudio Imbrenda <imbrenda@linux.ibm.com>
To:     Janosch Frank <frankja@linux.ibm.com>
Cc:     kvm@vger.kernel.org, borntraeger@de.ibm.com, thuth@redhat.com,
        pasic@linux.ibm.com, david@redhat.com, linux-s390@vger.kernel.org,
        linux-kernel@vger.kernel.org, scgl@linux.ibm.com,
        mimu@linux.ibm.com, nrb@linux.ibm.com
Subject: Re: [PATCH v11 07/19] KVM: s390: pv: module parameter to fence
 asynchronous destroy
Message-ID: <20220615115942.762ac791@p-imbrenda>
In-Reply-To: <bcbfcc87-aef4-d151-8e34-4646f1533c25@linux.ibm.com>
References: <20220603065645.10019-1-imbrenda@linux.ibm.com>
        <20220603065645.10019-8-imbrenda@linux.ibm.com>
        <bcbfcc87-aef4-d151-8e34-4646f1533c25@linux.ibm.com>
Organization: IBM
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On Wed, 15 Jun 2022 11:53:17 +0200
Janosch Frank <frankja@linux.ibm.com> wrote:

> On 6/3/22 08:56, Claudio Imbrenda wrote:
> > Add the module parameter "async_destroy", to allow the asynchronous
> > destroy mechanism to be switched off.  This might be useful for
> > debugging purposes.
> > 
> > The parameter is enabled by default.
> > 
> > Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
> > Reviewed-by: Janosch Frank <frankja@linux.ibm.com>  
> 
> Normally this would be one of the last patches in the series, no?

I need the variable to be already defined, because the subsequent
patches use it to fence things

> 
> > ---
> >   arch/s390/kvm/kvm-s390.c | 5 +++++
> >   1 file changed, 5 insertions(+)
> > 
> > diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> > index 76ad6408cb2c..49e27b5d7c3a 100644
> > --- a/arch/s390/kvm/kvm-s390.c
> > +++ b/arch/s390/kvm/kvm-s390.c
> > @@ -206,6 +206,11 @@ unsigned int diag9c_forwarding_hz;
> >   module_param(diag9c_forwarding_hz, uint, 0644);
> >   MODULE_PARM_DESC(diag9c_forwarding_hz, "Maximum diag9c forwarding per second, 0 to turn off");
> >   
> > +/* allow asynchronous deinit for protected guests, enable by default */
> > +static int async_destroy = 1;
> > +module_param(async_destroy, int, 0444);
> > +MODULE_PARM_DESC(async_destroy, "Asynchronous destroy for protected guests");
> > +
> >   /*
> >    * For now we handle at most 16 double words as this is what the s390 base
> >    * kernel handles and stores in the prefix page. If we ever need to go beyond  
>