Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication

[Stefan Hajnoczi]

On Thu, Dec 7, 2017 at 7:54 AM, Avi Cohen (A) <address@hidden> 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)
> **Question**:  What is the advantage of vhost-pci compared to this ?

Which mechanism do you mean?

vhost-pci will allow VM-to-VM communication without vmexits when
polling mode is used.  Does the mechanism you are thinking about
require vmexits?

Stefan