Date: Sun, 28 Feb 2010 22:00:04 GMT From: =?iso-8859-1?Q?Wei=DF=2C_J=FCrgen?= <weiss@uni-mainz.de> To: freebsd-xen@FreeBSD.org Subject: Re: kern/143340: [xen] FreeBSD 8-RELEASE XEN pvm networking doesn't work on solaris dom0's Message-ID: <201002282200.o1SM049T006314@freefall.freebsd.org>
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The following reply was made to PR kern/143340; it has been noted by GNATS.
From: =?iso-8859-1?Q?Wei=DF=2C_J=FCrgen?= <weiss@uni-mainz.de>
To: "'bug-followup@FreeBSD.org'" <bug-followup@FreeBSD.org>,
"'wonslung@gmail.com'" <wonslung@gmail.com>
Cc:
Subject: Re: kern/143340: [xen] FreeBSD 8-RELEASE XEN pvm networking doesn't
work on solaris dom0's
Date: Sun, 28 Feb 2010 22:43:56 +0100
the current FreeBSD frontend of the xn network driver does not check the ca=
pabilities
of the backend driver.=20
The following patch checks the backend features feature-sg (scatter/gather)
and feature-gso-tcpv4 (segmentation offload) and sets the frontend driver
capabilities accordingly.=20
There is still the problem with receive and transmit checksum offload.
I have no idea how to figure out what the backend supports. So
for opensolaris it seems necessary to disable checksum offload manually by
ifconfig xn0 -txcsum -rxcsum
Maybe it would make sense to change the default for checksum offload
if the backend does not support feature-sg and/or feature-gso-tcpv4.
--- netfront.c.orig 2009-10-25 02:10:29.000000000 +0100
+++ netfront.c 2010-02-28 18:08:20.000000000 +0100
@@ -236,6 +236,7 @@
u_int irq;
u_int copying_receiver;
u_int carrier;
+ u_int sg_allowed;
=09
/* Receive-ring batched refills. */
#define RX_MIN_TARGET 32
@@ -1432,7 +1433,7 @@
*/
for (m =3D m_head, nfrags =3D 0; m; m =3D m->m_next)
nfrags++;
- if (nfrags > MAX_SKB_FRAGS) {
+ if (nfrags > (sc->sg_allowed ? MAX_SKB_FRAGS : 1)) {
m =3D m_defrag(m_head, M_DONTWAIT);
if (!m) {
m_freem(m_head);
@@ -1788,6 +1789,35 @@
ifp->if_drv_flags &=3D ~(IFF_DRV_RUNNING | IFF_DRV_OACTIVE);
}
=20
+static void xennet_set_features(device_t dev, struct netfront_info *np)
+{
+ struct ifnet *ifp;
+ int val;
+
+ device_printf(dev, "backend features:");
+
+ if (xenbus_scanf(XBT_NIL, xenbus_get_otherend_path(np->xbdev), "feature-s=
g", NULL, "%d", &val) < 0)
+ val =3D 0;
+=09
+ np->sg_allowed =3D val;
+
+ if (val)
+ printf(" feature-sg");
+
+ if (xenbus_scanf(XBT_NIL, xenbus_get_otherend_path(np->xbdev), "feature-g=
so-tcpv4", NULL, "%d", &val) < 0)
+ val =3D 0;
+
+ if (val =3D=3D 0) {
+ ifp =3D np->xn_ifp;
+ ifp->if_capabilities &=3D ~(IFCAP_TSO4|IFCAP_LRO);
+ ifp->if_capenable &=3D ~(IFCAP_TSO4|IFCAP_LRO);
+ ifp->if_hwassist &=3D ~(CSUM_TSO);
+ } else
+ printf(" feature-gso-tcp4");
+
+ printf("\n");
+}
+
/* START of Xenolinux helper functions adapted to FreeBSD */
int
network_connect(struct netfront_info *np)
@@ -1820,6 +1850,8 @@
if (error)=20
return (error);
=09
+ xennet_set_features(np->xbdev, np);
+
/* Step 1: Reinitialise variables. */
netif_release_tx_bufs(np);
Juergen Weiss |Universitaet Mainz, Zentrum fuer Datenverarbeitung,
weiss@uni-mainz.de |55099 Mainz, Tel: +49(6131)39-26361, FAX: +49(6131)39-2=
6407
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