[lkml]   [2020]   [Nov]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH v4 00/17] Add VFIO mediated device support and DEV-MSI support for the idxd driver
Hi Jason

On Mon, Nov 02, 2020 at 09:20:36AM -0400, Jason Gunthorpe wrote:

> > of IDXD for guest drivers. These look and feel like IDXD, not another device
> > interface. In that sense if we move PF/VF mailboxes as
> > separate drivers i thought it feels a bit odd.
> You need this split anyhow, putting VFIO calls into the main idxd
> module is not OK.
> Plugging in a PCI device should not auto-load VFIO modules.

Yes, I agree that would be a good reason to separate them completely and
glue functionality with private APIs between the 2 modules.

- Separate mdev code from base idxd.
- Separate maintainers, so its easy to review and include. (But remember
they are heavily inter-dependent. They have to move to-gether)

Almost all SRIOV drivers today are just configured with some form of Kconfig
and those relevant files are compiled into the same module.

I think in *most* applications idxd would be operating in that mode, where
you have the base driver and mdev parts (like VF) compiled in if configured

Creating these private interfaces for intra-module are just 1-1 and not
general purpose and every accelerator needs to create these instances.

I wasn't sure focibly creating this firewall between the PF/VF interfaces
is actually worth the work every driver is going to require. I can see
where this is required when they offer separate functional interfaces
when we talk about multi-function in a more confined definition today.

idxd mdev's are purely a VF extension. It doesn't provide any different
function. For e.g. like an RDMA device that can provide iWarp, ipoib or
even multiplexing storage over IB. IDXD is a fixed function interface.

Sure having separate modules helps with that isolation. But I'm not
convinced if this simplifies, or complicates things more than what is
required for these device types.


 \ /
  Last update: 2020-11-02 17:21    [W:0.406 / U:0.344 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site