HVM guest hangs on block io

[Stefan Bader]

Release: Oneiric
Architecture: 64bit

Since moving from xen 4.1.0 to 4.1.1, starting a HVM guest from Oneiric dom0 (with the xl stack) results in the domU having issues accessing the emulated IDE device.

[Stefan Bader (smb)]

This has been identified as some problem related to certain qemu-dm versions which causes interrupts not to be delivered. An initial attempt to address this (http://xenbits.xen.org/hg/xen-4.1-testing.hg/rev/0f2b9b6c5a74) has been reverted recently because it caused problems with other guests.

[Stefan Bader (smb)]

This patch seems to solve the primary issue. It is not yet, anywhere upstream as far as I know. So it may cause other side effects or get changed before it is finally submitted.
With this applied I was able to boot pre-3.0 kernels as HVM guests under Oneiric again. However booting an Oneiric guest triggers the same issues with a change enabling IPI events and Xen spinlocks. This time the 4.1.1 hypervisor is supposed to support them.

[Stefan Bader (smb)]

Updating the patches (yes, two) to the latest version. The first one resolves the issue of the disk getting no interrupts. The second one will fix the emulated NIC getting no interrupts. This may or may not be counted as two different issues. I decided against it for the moment to keep things in one place.

[Stefan Bader (smb)]

Both patches are against the hypervisor code. The can be found in the staging/xen-4.1-testing repo:

http://xenbits.xen.org/hg/staging/xen-4.1-testing.hg/rev/50496ccde3c3
http://xenbits.xen.org/hg/staging/xen-4.1-testing.hg/rev/6239209bb560

[Launchpad Janitor (janitor)]

This bug was fixed in the package xen - 4.1.1-2ubuntu2

---------------
xen (4.1.1-2ubuntu2) oneiric; urgency=low

  * Clean up patches.
  * debian/patches/upstream-changeset-23146.patch,
    debian/patches/upstream-changeset-23147.patch: Fix booting with hvm
    domU. (LP: #832207)
 -- Chuck Short <email address hidden> Thu, 01 Sep 2011 13:13:47 -0400