Sounds good guys - I'll get cracking on this on Monday. Cheers, Mark
>-----Original Message----- >From: Jan Scheurich [mailto:[email protected]] >Sent: Friday, November 24, 2017 4:21 PM >To: Kevin Traynor <[email protected]>; Kavanagh, Mark B ><[email protected]>; [email protected] >Cc: [email protected]; Flavio Leitner <[email protected]>; Franck Baudin ><[email protected]>; Mooney, Sean K <[email protected]>; Ilya Maximets ><[email protected]>; Stokes, Ian <[email protected]>; Loftus, Ciara ><[email protected]>; Darrell Ball <[email protected]>; Aaron Conole ><[email protected]> >Subject: RE: [ovs-dev] [PATCH 2/2] netdev-dpdk: add support for vhost IOMMU >feature > >+1 >Jan > >> -----Original Message----- >> From: Kevin Traynor [mailto:[email protected]] >> Sent: Friday, 24 November, 2017 17:11 >> To: Mark Kavanagh <[email protected]>; [email protected] >> Cc: [email protected]; Flavio Leitner <[email protected]>; Franck >Baudin <[email protected]>; Mooney, Sean K >> <[email protected]>; Ilya Maximets <[email protected]>; Ian >Stokes <[email protected]>; Loftus, Ciara >> <[email protected]>; Darrell Ball <[email protected]>; Aaron Conole ><[email protected]>; Jan Scheurich >> <[email protected]> >> Subject: Re: [ovs-dev] [PATCH 2/2] netdev-dpdk: add support for vhost IOMMU >feature >> >> On 11/16/2017 11:01 AM, Mark Kavanagh wrote: >> > DPDK v17.11 introduces support for the vHost IOMMU feature. >> > This is a security feature, that restricts the vhost memory >> > that a virtio device may access. >> > >> > This feature also enables the vhost REPLY_ACK protocol, the >> > implementation of which is known to work in newer versions of >> > QEMU (i.e. v2.10.0), but is buggy in older versions (v2.7.0 - >> > v2.9.0, inclusive). As such, the feature is disabled by default >> > in (and should remain so, for the aforementioned older QEMU >> > verions). Starting with QEMU v2.9.1, vhost-iommu-support can >> > safely be enabled, even without having an IOMMU device, with >> > no performance penalty. >> > >> > This patch adds a new vhost port option, vhost-iommu-support, >> > to allow enablement of the vhost IOMMU feature: >> > >> > $ ovs-vsctl add-port br0 vhost-client-1 \ >> > -- set Interface vhost-client-1 type=dpdkvhostuserclient \ >> > options:vhost-server-path=$VHOST_USER_SOCKET_PATH \ >> > options:vhost-iommu-support=true >> > >> >> Hi Mark, All, >> >> I'm thinking about this and whether the current approach provides more >> than what is actually needed by users at the cost of making the user >> interface more complex. >> >> As an alternative, how about having a global other_config (to be set >> like vhost-socket-dir can be) for this instead of having to set it for >> each individual interface. It would mean that it would only have to be >> set once, instead of having this (ugly?!) option every time a vhost port >> is added, so it's a less intrusive change and I can't really think that >> a user would require to do this per vhostclient interface??? It's pain >> to have to add this at all for a bug in QEMU and I'm sure in 1/2/3 years >> time someone will say that users could still be using QEMU < 2.9.1 and >> we can't remove it, so it would be nice to keep it as discreet as >> possible as we're going to be stuck with it for a while. >> >> I assume that a user would only use one version of QEMU at a time and >> would either want or not want this feature. In the worst case, if that >> proved completely wrong in the future, then a per interface override >> could easily be added. Once there's a way to maintain backwards >> compatibility (which there would be) I'd rather err on the side of >> introducing just enough enough functionality over increasing complexity >> for the user. >> >> What do you think? >> >> thanks, >> Kevin. _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
