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Re: [Qemu-devel] [RFC PATCH v2 09/35] multi-process: setup PCI host brid
From: |
Gerd Hoffmann |
Subject: |
Re: [Qemu-devel] [RFC PATCH v2 09/35] multi-process: setup PCI host bridge for remote device |
Date: |
Tue, 18 Jun 2019 08:53:21 +0200 |
User-agent: |
NeoMutt/20180716 |
On Mon, Jun 17, 2019 at 11:15:39AM -0700, address@hidden wrote:
> From: Jagannathan Raman <address@hidden>
>
> PCI host bridge is setup for the remote device process. It is
> implemented using remote-pcihost object. It is an extension of the PCI
> host bridge setup by QEMU.
> Remote-pcihost configures a PCI bus which could be used by the remote
> PCI device to latch on to.
Hmm, this (and at least the next two patches) look like you just fake
everything the device emulation needs in the remote process.
I doubt this is a good long-term plan.
IIRC there was some discussion on the last kvm forum on the idea to
re-use the vfio API for pci emulation in a separate process, i.e. create
something like vfio-user. Have you considered this?
Sure, the lsi host adapter will probably need some refactoring so the
code can compiled into both qemu and a vfio-user server. But that way
the chance that this can be maintained long-term without too much
headache is much higher.
A small, well-defined interface will also make it easier to re-write the
device emulation in another language like rust or go.
The current patch series feels more like a early proof-of-concept than
something mergeable ...
cheers,
Gerd