Re: [PATCH v2] vfio: fix deadlock between group lock and kvm lock

Matthew Rosato
2023-02-02T12:52:57Z

On 2/1/23 11:10 PM, Tian, Kevin wrote:
>> From: Alex Williamson <alex.williamson@redhat.com>
>> Sent: Thursday, February 2, 2023 7:28 AM
>>>
>>> +#ifdef CONFIG_HAVE_KVM
>>> +static bool vfio_kvm_get_kvm_safe(struct vfio_device *device, struct kvm
>> *kvm)
>>
>> I'm tempted to name these vfio_device_get_kvm_safe() and only pass the
>> vfio_device, where of course we can get the kvm pointer from the group
>> internally.
>>
>
> I have a different thought. In the end the cdev series also need the similar
> safe get/put logic then it's better to keep it in vfio_main.c called by
> the group/cdev path individually.

Ah, I hadn't considered the cdev series - OK, I can move the functions back into vfio_main and externalize both via drivers/vfio/vfio.h so they can be called from group.c for this fix and then available to vfio_main.c already for cdev.