Re: [RFC PATCH] iommu/amd: fix a race in fetch_pte()

[Joerg Roedel]

Hi Qian,

On Mon, Apr 20, 2020 at 09:26:12AM -0400, Qian Cai wrote:
> 
> No dice. There could be some other races. For example,

Okay, I think I know what is happening. The increase_address_space()
function increases the address space, but does not update the
DTE and does not flush the old DTE from the caches. But this needs to
happen before domain->pt_root is updated, because otherwise another CPU
can come along and map something into the increased address-space which
is not yet accessible by the device because the DTE is not updated yet.

Regards,

	Joerg