On Tue, Sep 15, 2020 at 05:22:26PM -0700, Jacob Pan (Jun) wrote: > > If user space wants to bind page tables, create the PASID with > > /dev/sva, use ioctls there to setup the page table the way it wants, > > then pass the now configured PASID to a driver that can use it. > > Are we talking about bare metal SVA? What a weird term. > If so, I don't see the need for userspace to know there is a > PASID. All user space need is that my current mm is bound to a > device by the driver. So it can be a one-step process for user > instead of two. You've missed the entire point of the conversation, VDPA already needs more than "my current mm is bound to a device" > > PASID managment and binding is seperated from the driver(s) that are > > using the PASID. > > Why separate? Drivers need to be involved in PASID life cycle > management. For example, when tearing down a PASID, the driver needs to > stop DMA, IOMMU driver needs to unbind, etc. If driver is the control > point, then things are just in order. I am referring to bare metal SVA. Drivers can be involved and still have the uAPIs seperate. It isn't hard. Jason
