Re: [libvirt] [PATCH] qemu: Introduce VIRTIO_NET_F_STANDBY feature bit to virtio_net

On 6/4/2018 7:06 PM, Jason Wang wrote: > > > On 2018年06月05日 09:41, Samudrala, Sridhar wrote: >> Ping on this patch now that the kernel patches are accepted into >> davem's net-next tree. >> https://patchwork.ozlabs.org/cover/920005/ >> >> >> On 5/7/2018 4:09 PM, Sridhar Samudrala wrote: >>> This feature bit can be used by hypervisor to indicate virtio_net >>> device to >>> act as a standby for another device with the same MAC address. >>> >>> I tested this with a small change to the patch to mark the STANDBY >>> feature 'true' >>> by default as i am using libvirt to start the VMs. >>> Is there a way to pass the newly added feature bit 'standby' to qemu >>> via libvirt >>> XML file? >>> > > Maybe you can try qemu command line passthrough: > > https://libvirt.org/drvqemu.html#qemucommand It looks like this can be used to pass command line arguments to qemu. Is it possible to specify a virtio specific attribute via this method?

For ex: to say mrg_rxbuf is off we can add the following line to virtio section of the domain xml file. <host mrg_rxbuf='off'/> I think libvirt needs to be extended to to support the new 'standby' attribute via this mechanism. Adding Liane Stump and libvirt to the CC list.

Michael, Can we start with getting this patch into Qemu and an update to libvirt to support the 'standby' feature so that this feature can be enabled via some scripts/orchestration layer for now. We could improve this solution by enhancing Qemu to do automatic management of the addition/deletion of the primary device based on feature negotiation as a later patch.