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Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM comm
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication |
Date: |
Wed, 13 Dec 2017 22:59:10 +0200 |
> * VHOST_USER_SET_VRING_KICK
>
> Set up vring kick doorbell (unless bit 8 is set) before sending
> VHOST_USER_SET_VRING_KICK to the guest.
But guest can't use it, now can it?
What guest needs is a mapping to interrupts.
> * VHOST_USER_SET_VRING_CALL
>
> Set up the vring call doorbell (unless bit 8 is set) before sending
> VHOST_USER_SET_VRING_CALL to the guest.
Same here. what guest needs is mapping from io to notifications,
right?
---
> > I took a quick look and I doubt we can do something that is both
> > compatible with the existing vhost-user and will make it possible to
> > extend the protocol without qemu changes. Let's assume I pass a new
> > message over the vhost-user channel. How do we know it's safe to pass
> > it to the guest?
> >
> > That's why we gate any protocol change on a feature bit and must parse
> > all messages.
>
> QEMU must parse all messages and cannot pass through unknown messages.
> Think of QEMU vhost-pci as both a vhost-user slave to the other VM and
> a vhost-user master to the guest.
>
> QEMU changes are necessary when the vhost protocol is extended.
> Device interface changes are only necessary if doorbells or shared
> memory regions are added, any other protocol changes do not change the
> device interface.
>
> Stefan
I guess you have a different definition of a device interface than
myself - I consider it an interface change if a feature bit changes :)
--
MST
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, (continued)
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Wei Wang, 2017/12/08
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Stefan Hajnoczi, 2017/12/08
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Wang, Wei W, 2017/12/09
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Stefan Hajnoczi, 2017/12/11
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Wang, Wei W, 2017/12/11
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Stefan Hajnoczi, 2017/12/12
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Wei Wang, 2017/12/13
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Stefan Hajnoczi, 2017/12/13
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Michael S. Tsirkin, 2017/12/13
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Stefan Hajnoczi, 2017/12/13
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication,
Michael S. Tsirkin <=
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Stefan Hajnoczi, 2017/12/14
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Wei Wang, 2017/12/15
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Stefan Hajnoczi, 2017/12/15
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Maxime Coquelin, 2017/12/13
- Re: [Qemu-devel] [virtio-dev] Re: [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Stefan Hajnoczi, 2017/12/14
- Re: [Qemu-devel] [virtio-dev] Re: [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Michael S. Tsirkin, 2017/12/14
- Re: [Qemu-devel] [virtio-dev] Re: [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Maxime Coquelin, 2017/12/14
- Re: [Qemu-devel] [virtio-dev] Re: [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Michael S. Tsirkin, 2017/12/14
- Re: [Qemu-devel] [virtio-dev] Re: [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Maxime Coquelin, 2017/12/14
- Re: [Qemu-devel] [virtio-dev] Re: [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Stefan Hajnoczi, 2017/12/14