Re: [PATCH] vfio/pci: Handle concurrent vma faults

[Peter Xu]

On Wed, Mar 10, 2021 at 02:40:11PM -0400, Jason Gunthorpe wrote:
> On Wed, Mar 10, 2021 at 11:34:06AM -0700, Alex Williamson wrote:
> 
> > > I think after the address_space changes this should try to stick with
> > > a normal io_rmap_pfn_range() done outside the fault handler.
> > 
> > I assume you're suggesting calling io_remap_pfn_range() when device
> > memory is enabled,
> 
> Yes, I think I saw Peter thinking along these lines too
> 
> Then fault just always causes SIGBUS if it gets called

Indeed that looks better than looping in the fault().

But I don't know whether it'll be easy to move io_remap_pfn_range() to device
memory enablement.  If it's a two-step thing, we can fix the BUG_ON and vma
duplication issue first, then the full rework can be done in the bigger series
as what be chosen as the last approach.

Thanks,

-- 
Peter Xu