From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian Campbell Subject: Re: [PATCH net-next v4 1/5] xen-netback: add support for IPv6 checksum offload to guest Date: Mon, 14 Oct 2013 11:53:33 +0100 Message-ID: <1381748013.24708.102.camel@kazak.uk.xensource.com> References: <1381503982-1418-1-git-send-email-paul.durrant@citrix.com> <1381503982-1418-2-git-send-email-paul.durrant@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: , , Wei Liu , David Vrabel To: Paul Durrant Return-path: Received: from smtp.citrix.com ([66.165.176.89]:28213 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754097Ab3JNKzT (ORCPT ); Mon, 14 Oct 2013 06:55:19 -0400 In-Reply-To: <1381503982-1418-2-git-send-email-paul.durrant@citrix.com> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, 2013-10-11 at 16:06 +0100, Paul Durrant wrote: > Check xenstore flag feature-ipv6-csum-offload to determine if a > guest is happy to accept IPv6 packets with only partial checksum. > Also check analogous feature-ip-csum-offload to determine if a > guest is happy to accept IPv4 packets with only partial checksum > as a replacement for a negated feature-no-csum-offload value and > add a comment to deprecate use of feature-no-csum-offload. > > Signed-off-by: Paul Durrant > Cc: Wei Liu > Cc: David Vrabel > Cc: Ian Campbell Shouldn't this come later in the series, i.e. after netback is actually able to cope with ipv6 offloads? > diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h > index 5715318..b4a9a3c 100644 > --- a/drivers/net/xen-netback/common.h > +++ b/drivers/net/xen-netback/common.h > @@ -153,7 +153,8 @@ struct xenvif { > u8 can_sg:1; > u8 gso:1; > u8 gso_prefix:1; > - u8 csum:1; > + u8 ip_csum:1; > + u8 ipv6_csum:1; Why not ipv4_csum for consistency/unambiguity? > diff --git a/include/xen/interface/io/netif.h b/include/xen/interface/io/netif.h > index eb262e3..d9fb44739 100644 > --- a/include/xen/interface/io/netif.h > +++ b/include/xen/interface/io/netif.h > @@ -51,6 +51,16 @@ > */ > > /* > + * "feature-no-csum-offload" was used to turn off IPv4 TCP/UDP checksum > + * offload but is now deprecated. Two new feature flags should now be used > + * to control checksum offload: How is a frontend to know which sort of backend it is talking too? Is there going to be a feature flag to indicate support for these new flags? In particular a new frontend running on an old backend needs to know that it needs to set no-csum-offload instead of ip-csum-offload somehow. > + * "feature-ip-csum-offload" should be used to turn IPv4 TCP/UDP checksum "ipv4" again? > + * offload on or off. If it is missing then the feature is assumed to be on. > + * "feature-ipv6-csum-offload" should be used to turn IPv6 TCP/UDP checksum > + * offload on or off. If it is missing then the feature is assumed to be off. > + */ > + > +/* > * This is the 'wire' format for packets: > * Request 1: xen_netif_tx_request -- XEN_NETTXF_* (any flags) > * [Request 2: xen_netif_extra_info] (only if request 1 has XEN_NETTXF_extra_info)