Subject: Re: [PATCH V6 mlx5-next 08/15] vfio: Define device migration protocol v2

From: Cornelia Huck <[email-masked]>
Date: Tue, 01 Feb 2022 13:18:29 +0100

On Tue, Feb 01 2022, Jason Gunthorpe <[email-masked]> wrote:

> On Tue, Feb 01, 2022 at 01:06:51PM +0100, Cornelia Huck wrote:
>> On Sun, Jan 30 2022, Yishai Hadas <[email-masked]> wrote:
>> 
>> > @@ -1582,6 +1760,10 @@ static int vfio_ioctl_device_feature(struct vfio_device *device,
>> >  		return -EINVAL;
>> >  
>> >  	switch (feature.flags & VFIO_DEVICE_FEATURE_MASK) {
>> > +	case VFIO_DEVICE_FEATURE_MIGRATION:
>> > +		return vfio_ioctl_device_feature_migration(
>> > +			device, feature.flags, arg->data,
>> > +			feature.argsz - minsz);
>> >  	default:
>> >  		if (unlikely(!device->ops->device_feature))
>> >  			return -EINVAL;
>> > @@ -1597,6 +1779,8 @@ static long vfio_device_fops_unl_ioctl(struct file *filep,
>> >  	struct vfio_device *device = filep->private_data;
>> >  
>> >  	switch (cmd) {
>> > +	case VFIO_DEVICE_MIG_SET_STATE:
>> > +		return vfio_ioctl_mig_set_state(device, (void __user *)arg);
>> >  	case VFIO_DEVICE_FEATURE:
>> >  		return vfio_ioctl_device_feature(device, (void __user *)arg);
>> >  	default:
>> 
>> Not really a critique of this patch, but have we considered how mediated
>> devices will implement migration?
>
> Yes
>
>> I.e. what parts of the ops will need to be looped through the mdev
>> ops?
>
> I've deleted mdev ops in every driver except the intel vgpu, once
> Christoph's patch there is merged mdev ops will be almost gone
> completely.

Ok, if there's nothing left to do, that's fine. (I'm assuming that the
Intel vgpu patch is on its way in? I usually don't keep track of things
I'm not directly involved with.)