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Date: Thu, 7 Dec 2017 15:33:54 +0200
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Subject: Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM
 communication
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To: "Avi Cohen (A)" <avi.cohen@huawei.com>
Cc: Stefan Hajnoczi <stefanha@gmail.com>, Wei Wang <wei.w.wang@intel.com>, Stefan Hajnoczi <stefanha@redhat.com>, "virtio-dev@lists.oasis-open.org" <virtio-dev@lists.oasis-open.org>, "Yang, Zhiyong" <zhiyong.yang@intel.com>, "jan.kiszka@siemens.com" <jan.kiszka@siemens.com>, "jasowang@redhat.com" <jasowang@redhat.com>, "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>, "marcandre.lureau@redhat.com" <marcandre.lureau@redhat.com>, "pbonzini@redhat.com" <pbonzini@redhat.com>

On Thu, Dec 07, 2017 at 07:54:48AM +0000, Avi Cohen (A) wrote:
> There is already a  virtio mechanism in which 2 VMs assigned a virtio device , are communicating via a veth pair  in the host .
> KVM just passes  a pointer of the page of the writer VM to the reader VM - resulting  in  excellent performance (no vSwitch in the middle)

What exactly do you refer to?

> **Question**:  What is the advantage of vhost-pci compared to this ?
> Best Regards
> Avi

I suspect what's missing in this thread is the original motivation rfc:
http://virtualization.linux-foundation.narkive.com/A7FkzAgp/rfc-vhost-user-enhancements-for-vm2vm-communication