Re: [PATCH v6 05/20] vfio: mdev: common lib code for setting up Interrupt Message Store

Dave Jiang
2021-05-28T16:38:03Z

On 5/28/2021 5:21 AM, Jason Gunthorpe wrote:
> On Thu, May 27, 2021 at 06:49:59PM -0700, Dave Jiang wrote:
>>>> +static int mdev_msix_enable(struct mdev_irq *mdev_irq, int nvec)
>>>> +{
>>>> + struct mdev_device *mdev = irq_to_mdev(mdev_irq);
>>>> + struct device *dev;
>>>> + int rc;
>>>> +
>>>> + if (nvec != mdev_irq->num)
>>>> + return -EINVAL;
>>>> +
>>>> + if (mdev_irq->ims_num) {
>>>> + dev = &mdev->dev;
>>>> + rc = msi_domain_alloc_irqs(dev_get_msi_domain(dev), dev, mdev_irq->ims_num);
>>> Huh? The PCI device should be the only device touching IRQ stuff. I'm
>>> nervous to see you mix in the mdev struct device into this function.
>> As we talked about in the other thread. We have a single IMS domain per
>> device. The domain is set to the mdev 'struct device' and we allocate the
>> vectors to each mdev 'struct device' so we can manage those IMS vectors
>> specifically for that mdev.
> That is not the point, I'm asking if you should be calling
> dev_set_msi_domain(mdev) at all

I'm not familiar with the standard way of doing this. Should I not set
the domain to the mdev 'struct device' because I can have multiple mdev
using the same domain? With the domain set, I am able to retrieve it and
call the msi_domain_alloc_irqs() in common code. Alternatively we can
pass in the domain during init and not rely on dev->msi_domain.

>
> Jason