Re: AMD SME encrpytion and PCI BAR pages to user space

[Jason Gunthorpe]

On Mon, Oct 19, 2020 at 12:11:36PM -0500, Tom Lendacky wrote:

> > Hum, I assume it is broken also. Actually quite a swath of drivers
> > and devices will be broken under this :\
> 
> Not sure what you mean by the last statement - in general or when running
> under VFIO/DPDK? In general, traditional in kernel drivers work just fine
> under SME without any changes.

Split user/kernel drivers are common enough. Looks like maybe ~50
drivers in the kernel potentially are mmaping IO memory so would be
broken here.

Looking for pgprot_noncached() or pgprot_writecombine() around VMA
mappings is a pretty good clue it is working on IO memory.

I checked through the infiniband ones and they seem to be using
io_remap vs remap properly, but other places may need fixing.

Jason