Re: [RFT][PATCH v1 5/6] vfio/ccw: Add kmap_local_page() for memcpy

Jason Gunthorpe
2022-06-20T15:40:05Z

On Sun, Jun 19, 2022 at 11:32:07PM -0700, Christoph Hellwig wrote:

> > This helps because we now block io memory from ever getting into these
> > call paths. I'm pretty sure this is a serious security bug, but would
> > let the IBM folks remark as I don't know it all that well..
>
> Prevent as in crash when trying to convert it to a page?

That or when calling memcpy() on an IO memory PFN that the guest
passed into the dma s/g list the ccw driver is processing.

Jason