Re: [PATCH v4 06/17] PCI: add SIOV and IMS capability detection

[Christoph Hellwig]

On Sat, Nov 14, 2020 at 01:18:37PM -0800, Raj, Ashok wrote:
> On Sat, Nov 14, 2020 at 10:34:30AM +0000, Christoph Hellwig wrote:
> > On Thu, Nov 12, 2020 at 11:42:46PM +0100, Thomas Gleixner wrote:
> > > DMI vendor name is pretty good final check when the bit is 0. The
> > > strings I'm aware of are:
> > > 
> > > QEMU, Bochs, KVM, Xen, VMware, VMW, VMware Inc., innotek GmbH, Oracle
> > > Corporation, Parallels, BHYVE, Microsoft Corporation
> > > 
> > > which is not complete but better than nothing ;)
> > 
> > Which is why I really think we need explicit opt-ins for "native"
> > SIOV handling and for paravirtualized SIOV handling, with the kernel
> > not offering support at all without either or a manual override on
> > the command line.
> 
> opt-in by device or kernel? The way we are planning to support this is:

opt-in by the platform.  Not sure if an ACPI interface or something else
would be best.  But basically the kernel needs to be able to query:

Does this platform claim to support IMS, and if yes how.  If there is no
answer we need assume the platform doesn't.