Re: [PATCHv8 00/11] Linear Address Masking enabling

From: Jason Gunthorpe
Date: Tue Sep 20 2022 - 20:01:38 EST


On Tue, Sep 20, 2022 at 01:44:30PM -0700, Jacob Pan wrote:

> > In general I'm not so keen on arch unique code for general ideas like
> > this (ARM probably has the same issue), but sure it could work.
> >
> Creating an abstraction seems to belong to a separate endeavor when we
> have more than one user. For now, are you ok with the current approach?

Sure, just don't give it a silly name like pasid or sva

> > You need to assert that the page table format is one of the
> > formats that the iommu understands and configure the iommu to match
> > it. It is a very simple question about what ruleset and memory layout
> > govern the page table memory used by the CPU.

> the problem is more relevant to things like canonical address
> requirement than page table format.

The translation of an VA to a PA is entirely within the realm of the
page table format, IMHO. If the rules change then the format clearly
differs, even if your arch documents talk about "canonical address" or
something to define the different parsing behaviors.

Jason