Re: [PATCH 3/3] vfio-pci: Invalidate mmaps and block MMIO access on disabled memory

[Jason Gunthorpe]

On Tue, May 05, 2020 at 11:12:27AM -0600, Alex Williamson wrote:
> 
> As noted in the comment, the fault handler can simply do:
> 
> mutex_lock(&vdev->vma_lock);
> down_read(&vdev->memory_lock);
> 
> This should be deadlock free now, so we can drop the retry handling

That does look like the right direction, because the memory_lock can
be done at the very end it means it doesn't need to be nested inside
mmap_sem

This is much cleaner!

Jason