Re: [virtio-comment] Re: [PATCH v1 3/8] device-context: Define the device context fields for device migration

From
Michael S. Tsirkin <>
Date
2023-10-30T11:27:56+00:00
ID
Thread
Re: [virtio-comment] Re: [PATCH v1 3/8] device-context: Define the device context fields for device migration
On Thu, Oct 26, 2023 at 07:04:38AM +0000, Parav Pandit wrote:
> 1. It breaks the future TDISP model

I really think brinding in TDISP muddies the waters a lot and
should be avoided. We simply won't know until someone does the
legwork and proposed the necessary spec extensions.
In particular current legacy access commands are I thn


> 2. Without hypervisor getting involved, all the member device MMIO space is accessible which follows the efficiency and equivalency principle of Jason listed paper
> 
> I hope you are not implying to trap+emulate virtio interfaces (which is not listed in the pci-spec) in hypervisor for member passthrough devices.

I feel this discussion will keep meandering because the terminology is
vague. There's no single thing that is called "passthrough" -
vendors just build what is expedient with current hardware and
software. Nvidia has a bunch of people working on vfio so they
call that passthrough, Red Hat has people working on VDPA and
they call that passthrough, etc.


Before I mute this discussion for good, does anyone here have any
feeling progress is made? What kind of progress?

-- 
MST