Re: [PATCH v4 04/14] PCI/P2PDMA: Clear ACS P2P flags for all devices behind switches

Stephen Bates
2018-05-11T22:24:59Z

All

> Alex (or anyone else) can you point to where IOVA addresses are generated?

A case of RTFM perhaps (though a pointer to the code would still be appreciated).

https://www.kernel.org/doc/Documentation/Intel-IOMMU.txt

Some exceptions to IOVA
-----------------------
Interrupt ranges are not address translated, (0xfee00000 - 0xfeefffff).
The same is true for peer to peer transactions. Hence we reserve the
address from PCI MMIO ranges so they are not allocated for IOVA addresses.

Cheers

Stephen