[libvirt] [PATCH] Add support for 'passthru' mode for direct network interfaces

[D. Herrendoerfer]

On May 11, 2011, at 12:21 AM, Eric Blake wrote:
>
> Missing corresponding documentation in docs/formatdomain.html.in to
> describe the new mode.
>
> What happens if you try to use this mode but you have an older kernel?
> Do we need to add any sanity checking to give a saner error message  
> than
> just blindly trying the string and reporting back whatever message  
> gets
> returned about an unknown argument?
>
> The rest of this patch looks okay to me (with my disclaimer that I've
> never used an SRIOV card), but I'd rather wait for a v2 than push this
> without documentation.
>
> -- 
> Eric Blake   eblake at redhat.com    +1-801-349-2682
> Libvirt virtualization library http://libvirt.org
>

This patch includes the documentation part.

The error returned by libvirt when a using an older kernel
is imho sufficient to point to the macvtap setup. Apart from that
I doubt that someone will use this feature by chance. But still - I
believe the error returned is detailed enough for now.

Signed-off-by: Dirk Herrendoerfer <d.herrendoerfer at  
herrendoerfer.name>

diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
index 989dcf6..3f6bec8 100644
--- a/docs/formatdomain.html.in
+++ b/docs/formatdomain.html.in
@@ -1429,6 +1429,12 @@
       external router or gateway and that device sends them back to the
       host. This procedure is followed if either the source or  
destination
       device is in <code>private</code> mode.</dd>
+      <dt><code>passthru</code></dt>
+      <dd>This feature allows to attach a virtual function of a SRIOV  
capable
+      NIC directly to a VM without loosing the migration capability.
+      All packets are sent to the VF/IF of the configured network  
device.
+      Depending on the capabilities of the device additional  
prerequisites or
+      limitations may apply. <span class="since">(Since Linux  
2.6.38.)</span></dd>
     </dl>

<pre>
diff --git a/docs/schemas/domain.rng b/docs/schemas/domain.rng
index 7163c6e..e2a66ae 100644
--- a/docs/schemas/domain.rng
+++ b/docs/schemas/domain.rng
@@ -2351,7 +2351,7 @@
   </define>
   <define name="bridgeMode">
     <data type="string">
-      <param name="pattern">(vepa|bridge|private)</param>
+      <param name="pattern">(vepa|bridge|private|passthru)</param>
     </data>
   </define>
   <define name="addrMAC">
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index d3efec6..4c4bfad 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -383,7 +383,8 @@ VIR_ENUM_IMPL(virDomainSeclabel,  
VIR_DOMAIN_SECLABEL_LAST,
VIR_ENUM_IMPL(virDomainNetdevMacvtap,  
VIR_DOMAIN_NETDEV_MACVTAP_MODE_LAST,
               "vepa",
               "private",
-              "bridge")
+              "bridge",
+              "passthru" )

VIR_ENUM_IMPL(virVirtualPort, VIR_VIRTUALPORT_TYPE_LAST,
               "none",
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index a0f820c..70943f9 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -335,6 +335,7 @@ enum virDomainNetdevMacvtapType {
     VIR_DOMAIN_NETDEV_MACVTAP_MODE_VEPA,
     VIR_DOMAIN_NETDEV_MACVTAP_MODE_PRIVATE,
     VIR_DOMAIN_NETDEV_MACVTAP_MODE_BRIDGE,
+    VIR_DOMAIN_NETDEV_MACVTAP_MODE_PASSTHRU,

     VIR_DOMAIN_NETDEV_MACVTAP_MODE_LAST,
};
diff --git a/src/util/macvtap.c b/src/util/macvtap.c
index a7af0cb..1b274cc 100644
--- a/src/util/macvtap.c
+++ b/src/util/macvtap.c
@@ -473,6 +473,9 @@ macvtapModeFromInt(enum virDomainNetdevMacvtapType  
mode)
     case VIR_DOMAIN_NETDEV_MACVTAP_MODE_BRIDGE:
         return MACVLAN_MODE_BRIDGE;

+    case VIR_DOMAIN_NETDEV_MACVTAP_MODE_PASSTHRU:
+        return MACVLAN_MODE_PASSTHRU;
+
     case VIR_DOMAIN_NETDEV_MACVTAP_MODE_VEPA:
     default:
         return MACVLAN_MODE_VEPA;
@@ -546,7 +549,7 @@ configMacvtapTap(int tapfd, int vnet_hdr)
  *    be NULL if this function is supposed to choose a name
  * @macaddress: The MAC address for the macvtap device
  * @linkdev: The interface name of the NIC to connect to the external  
bridge
- * @mode: int describing the mode for 'bridge', 'vepa' or 'private'.
+ * @mode: int describing the mode for 'bridge', 'vepa', 'private' or  
'passthru'.
  * @vnet_hdr: 1 to enable IFF_VNET_HDR, 0 to disable it
  * @vmuuid: The UUID of the VM the macvtap belongs to
  * @virtPortProfile: pointer to object holding the virtual port  
profile data
diff --git a/src/util/macvtap.h b/src/util/macvtap.h
index 54205c7..c45dd13 100644
--- a/src/util/macvtap.h
+++ b/src/util/macvtap.h
@@ -92,6 +92,7 @@ void delMacvtap(const char *ifname,
#  define MACVTAP_MODE_PRIVATE_STR  "private"
#  define MACVTAP_MODE_VEPA_STR     "vepa"
#  define MACVTAP_MODE_BRIDGE_STR   "bridge"
+#  define MACVTAP_MODE_PASSTHRU_STR "passthru"

int vpAssociatePortProfileId(const char *macvtap_ifname,
                              const unsigned char *macvtap_macaddr,