> From: Jason Gunthorpe <jgg@xxxxxxxxxx> > Sent: Thursday, September 12, 2024 7:08 AM > > On Wed, Sep 11, 2024 at 08:13:01AM +0000, Tian, Kevin wrote: > > > Probably there is a good reason e.g. for simplification or better > > aligned with hw accel stuff. But it's not explained clearly so far. > > Probably the most concrete thing is if you have a direct assignment > invalidation queue (ie DMA'd directly by HW) then it only applies to a > single pIOMMU and invalidation commands placed there are unavoidably > limited in scope. > > This creates a representation problem, if we have a vIOMMU that spans > many pIOMMUs but invalidations do some subset how to do we model > that. Just saying the vIOMMU is linked to the pIOMMU solves this > nicely. > yes that is a good reason. btw do we expect the VMM to try-and-fail when deciding whether a new vIOMMU object is required when creating a new vdev?
