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

[Kirill A. Shutemov]

On Mon, Sep 12, 2022 at 03:55:02PM -0700, Jacob Pan wrote:
> Hi Dave,
> 
> On Mon, 12 Sep 2022 14:41:56 -0700, Dave Hansen <dave.hansen@xxxxxxxxx>
> wrote:
> 
> > On 9/12/22 13:39, Jacob Pan wrote:
> > >>> +	if (pasid_valid(mm->pasid) && !forced) {  
> > > I don't think this works since we have lazy pasid free.  for example,
> > > after all the devices did sva_unbind, mm->pasid  we'll remain valid
> > > until mmdrop(). LAM  should be supported in this case.  
> > 
> > Nah, it works fine.
> > It just means that the rules are "you can't do LAM if your process
> > *EVER* got a PASID" instead of "you can't do LAM if you are actively
> > using your PASID".
> Sure it works if you change the rules, but this case need to documented.
> 
> > 
> > We knew that PASID use would be a one-way trip for a process when we
> > moved to the simplified implementation.  This is just more fallout from
> > that.  It's fine.
> > 
> Is LAM also a one-way trip?

Yes.

-- 
  Kiryl Shutsemau / Kirill A. Shutemov