This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
Home Products Support Community News


Re: [Xen-devel] regression with c/s 21223

To: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Subject: Re: [Xen-devel] regression with c/s 21223
From: Jim Fehlig <jfehlig@xxxxxxxxxx>
Date: Fri, 07 May 2010 07:37:18 -0600
Cc: Xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>, Ryan O'Connor <rjo@xxxxxxxxx>
Delivery-date: Fri, 07 May 2010 06:38:18 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <C8098E2C.139E6%keir.fraser@xxxxxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <C8098E2C.139E6%keir.fraser@xxxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Thunderbird (X11/20081112)
Keir Fraser wrote:
> On 07/05/2010 04:36, "Jim Fehlig" <jfehlig@xxxxxxxxxx> wrote:
>> Frankly, I'm not sure how best to handle this case.  The current
>> philosophy seems to be treat all 'tap:foo' devices as blktap2 (see c/s
>> 19874 - author cc'd), but fall back to blktap1 if blktap2 is not found
>> when domU is started.  I'm certainly having problems differentiating
>> between the two in to_sxp().
>> Any suggestions on how to prevent the bug reported in [1] without this
>> new regression?
> Way outside my comfort zone with xend I'm afraid. Do you think we need
> explicit differentiation between tap and tap2?

That is certainly an approach we are considering for our Xen 4.0-based
packages - see attached patch.  As mentioned previously, we are not yet
supporting blktap2 so such a change seems appropriate in our case.

I'm hoping some of the folks that integrated blktap2 in xend can provide


Index: xen-4.0.0-testing/tools/python/xen/xm/main.py
--- xen-4.0.0-testing.orig/tools/python/xen/xm/main.py
+++ xen-4.0.0-testing/tools/python/xen/xm/main.py
@@ -2629,8 +2629,10 @@ def xm_usb_list_assignable_devices(args)
 def parse_block_configuration(args):
     dom = args[0]
-    if args[1].startswith('tap:'):
+    if args[1].startswith('tap2:'):
         cls = 'tap2'
+    elif args[1].startswith('tap:'):
+        cls = 'tap'
         cls = 'vbd'
Index: xen-4.0.0-testing/tools/python/xen/xm/create.py
--- xen-4.0.0-testing.orig/tools/python/xen/xm/create.py
+++ xen-4.0.0-testing/tools/python/xen/xm/create.py
@@ -791,8 +791,10 @@ def configure_disks(config_devs, vals):
     """Create the config for disks (virtual block devices).
     for (uname, dev, mode, backend, protocol) in vals.disk:
-        if uname.startswith('tap:'):
+        if uname.startswith('tap2:'):
             cls = 'tap2'
+        elif uname.startswith('tap:'):
+            cls = 'tap'
             cls = 'vbd'
Xen-devel mailing list