Linux Virtualization - Jul 2020 - [PATCH v5 2/2] s390: virtio: PV needs VIRTIO I/O device protection

On Thu, 9 Jul 2020 12:51:58 +0200
Pierre Morel <pmorel at linux.ibm.com> wrote:
> >> +int arch_validate_virtio_features(struct virtio_device *dev)
> >> +{
> >> +	if (!is_prot_virt_guest())
> >> +		return 0;
> >> +
> >> +	if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) {
> >> +		dev_warn(&dev->dev, "device must provide
VIRTIO_F_VERSION_1\n");
> > 
> > I'd probably use "legacy virtio not supported with protected
> > virtualization".
> >   
> >> +		return -ENODEV;
> >> +	}
> >> +
> >> +	if (!virtio_has_feature(dev, VIRTIO_F_IOMMU_PLATFORM)) {
> >> +		dev_warn(&dev->dev,
> >> +			 "device must provide VIRTIO_F_IOMMU_PLATFORM\n");  
> > 
> > "support for limited memory access required for protected
> > virtualization"
> > 
> > ?
> > 
> > Mentioning the feature flag is shorter in both cases, though.  
> 
> And I think easier to look for in case of debugging purpose.
> I change it if there is more demands.
Not all our end users are kernel and/or qemu developers. I find the
messages from v4 less technical, more informative, and way better.

Regards,
Halil

On 2020-07-09 16:47, Halil Pasic wrote:
> On Thu, 9 Jul 2020 12:51:58 +0200
> Pierre Morel <pmorel at linux.ibm.com> wrote:
> 
>>>> +int arch_validate_virtio_features(struct virtio_device *dev)
>>>> +{
>>>> +	if (!is_prot_virt_guest())
>>>> +		return 0;
>>>> +
>>>> +	if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) {
>>>> +		dev_warn(&dev->dev, "device must provide
VIRTIO_F_VERSION_1\n");
>>>
>>> I'd probably use "legacy virtio not supported with
protected
>>> virtualization".
>>>    
>>>> +		return -ENODEV;
>>>> +	}
>>>> +
>>>> +	if (!virtio_has_feature(dev, VIRTIO_F_IOMMU_PLATFORM)) {
>>>> +		dev_warn(&dev->dev,
>>>> +			 "device must provide
VIRTIO_F_IOMMU_PLATFORM\n");
>>>
>>> "support for limited memory access required for protected
>>> virtualization"
>>>
>>> ?
>>>
>>> Mentioning the feature flag is shorter in both cases, though.
>>
>> And I think easier to look for in case of debugging purpose.
>> I change it if there is more demands.
> 
> Not all our end users are kernel and/or qemu developers. I find the
> messages from v4 less technical, more informative, and way better.
> 
> Regards,
> Halil
> 
Can you please tell me the messages you are speaking of, because for me 
the warning's messages are exactly the same in v4 and v5!?

I checked many times, but may be I still missed something.

Regards,
Pierre


-- 
Pierre Morel
IBM Lab Boeblingen

On Thu, 9 Jul 2020 16:51:04 +0200
Pierre Morel <pmorel at linux.ibm.com> wrote:
> 
> 
> On 2020-07-09 16:47, Halil Pasic wrote:
> > On Thu, 9 Jul 2020 12:51:58 +0200
> > Pierre Morel <pmorel at linux.ibm.com> wrote:
> > 
> >>>> +int arch_validate_virtio_features(struct virtio_device
*dev)
> >>>> +{
> >>>> +	if (!is_prot_virt_guest())
> >>>> +		return 0;
> >>>> +
> >>>> +	if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) {
> >>>> +		dev_warn(&dev->dev, "device must provide
VIRTIO_F_VERSION_1\n");
> >>>
> >>> I'd probably use "legacy virtio not supported with
protected
> >>> virtualization".
> >>>    
> >>>> +		return -ENODEV;
> >>>> +	}
> >>>> +
> >>>> +	if (!virtio_has_feature(dev, VIRTIO_F_IOMMU_PLATFORM)) {
> >>>> +		dev_warn(&dev->dev,
> >>>> +			 "device must provide
VIRTIO_F_IOMMU_PLATFORM\n");
> >>>
> >>> "support for limited memory access required for protected
> >>> virtualization"
> >>>
> >>> ?
> >>>
> >>> Mentioning the feature flag is shorter in both cases, though.
> >>
> >> And I think easier to look for in case of debugging purpose.
> >> I change it if there is more demands.
> > 
> > Not all our end users are kernel and/or qemu developers. I find the
> > messages from v4 less technical, more informative, and way better.
> > 
> > Regards,
> > Halil
> > 
> 
> Can you please tell me the messages you are speaking of, because for me 
> the warning's messages are exactly the same in v4 and v5!?
> 
> I checked many times, but may be I still missed something.
> 
Sorry, my bad. My brain is over-generating. The messages where discussed
at v3 and Connie made a very similar proposal to the one above which I
seconded (for reference look at Message-ID:
<833c71f2-0057-896a-5e21-2c6263834402 at linux.ibm.com>). I was under the
impression that it got implemented in v4, but it was not. That's why I
ended up talking bs.

Regards,
Halil