Re: [PATCH v7 09/22] s390: vfio-ap: register matrix device with VFIO mdev framework

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Mon, 30 Jul 2018 13:24:24 +0200
Pierre Morel <pmorel@xxxxxxxxxxxxx> wrote:

> On 30/07/2018 11:49, Cornelia Huck wrote:
> > On Fri, 27 Jul 2018 16:17:47 +0200
> > Halil Pasic <pasic@xxxxxxxxxxxxx> wrote:
> >  
> >> On 07/26/2018 09:54 PM, Christian Borntraeger wrote:  
> >>> @@ -65,6 +66,21 @@ static int vfio_ap_matrix_dev_create(void)
> >>>    {
> >>>    	int ret;
> >>>    
> >>> +	mutex_init(&matrix_dev.lock);
> >>> +	INIT_LIST_HEAD(&matrix_dev.mdev_list);
> >>> +
> >>> +	/* Test if PQAP(QCI) instruction is available */
> >>> +	if (test_facility(12)) {
> >>> +		ret = ap_qci(&matrix_dev.info);
> >>> +		if (ret && (ret != -EOPNOTSUPP)) {  
> >> After Connie's curiosity was piqued I gave this another look. If
> >> I read the ap_qci() documentation and code correctly, it can return
> >> either 0 or -EOPNOTSUPP, but nothing else. So basically this
> >> is a dead branch.  
> > Can it return -EOPNOTSUPP if facility 12 is present?  
> 
> I do not think it is reasonable to continue if
> we stated that facility 12 is present but the ap_qci function failed.
> 
> So I propose that we return an error and break the insmod.

So, would that be a bug? If yes, returning an error makes sense.

(I can't check the documentation to find out about the interaction
between facility 12 and PQAP(QCI)...)
--
To unsubscribe from this list: send the line "unsubscribe linux-s390" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [Kernel Development]     [Kernel Newbies]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite Info]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Samba]     [Linux Media]     [Device Mapper]

  Powered by Linux