Re: [PATCH v1 0/4] virtio-msg transport layer

Bertrand Marquis
2026-02-25T13:30:13Z

Hi Demi,

> On 25 Feb 2026, at 14:12, Demi Marie Obenour <demiobenour@gmail.com> wrote:
>
> On 2/25/26 08:09, Manivannan Sadhasivam wrote:
>> On Wed, Feb 25, 2026 at 07:53:38AM -0500, Demi Marie Obenour wrote:
>>> On 2/25/26 02:45, Manivannan Sadhasivam wrote:
>>>> Hi Bertrand,
>>>>
>>>> On Fri, Feb 20, 2026 at 09:02:12AM +0000, Bertrand Marquis wrote:
>>>>> Hi Parav,
>>>
>>> (snip)
>>>
>>>>>> How can one implement a transport without defining the basic data transfer semantics?
>>>>>
>>>>> We did a lot of experiments and we are feature equivalent to PCI, MMIO or Channel I/O.
>>>>> If anything is missing, we are more than happy to discuss it and solve the issue.
>>>>>
>>>>
>>>> I'd love to have this transport over PCI because it addresses the shortcomings
>>>> of the existing PCI transport which just assumes that every config space access\
>>>> is trap and emulate.
>>>
>>> Would you mind elaborating on "over PCI"?
>>>
>>> I can see two meanings for this:
>>>
>>> 1. Virtio-msg over a physical PCI bus for heterogeneous multiprocessing
>>> environments.
>>>
>>> 2. Virtio-msg over an emulated PCI bus for QEMU, Cloud Hypervisor,
>>> and other existing VMMs.
>>>
>>> Which one are you referring to?
>>>
>>
>> Physical PCI bus, that's why I mentioned 'trap and emulate' which only applies
>> to emulated PCI bus.
>
> Is virtio-msg appropriate when the PCI bus is emulated, or should
> the existing PCI transport be used instead?

No existing PCI transport should be used, virtio msg over PCI is just for a specific case
and definitely not when virtio devices are pci devices.

Cheers
Bertrand

> --
> Sincerely,
> Demi Marie Obenour (she/her/hers)<OpenPGP_0xB288B55FFF9C22C1.asc>

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