Ubuntu
linux package

  1. Bug #1081054
  2. Comment #2

Comment 2 for bug 1081054

Revision history for this message
Stefano Panella (stefano-panella) wrote :

The panic is happening if we but the ubuntu kernel as HVM but we disable XEN flag from cpuid.
This scenario is useful if we want to boot the guest as a pure non XEN awere HVM guest. In this case qemu is still emulating platform_pci and since there is the driver in the kernel for it the probe gets called.

Commit b9136d207f0c05c96c6b9c980fa7f7fd541a65a8 allow the driver to be probed in any case (even if we do not tell the guest is running under xen) and in the probe try to use xen structures which are uninitialised.

Commit 38ad4f4b6cc713b3c42cb4252688ef5c296d7455 adds a check in platform_pci driver code to exit if the guest is not running in xen environment (cpuid does not report XEN).

In bare metal case there is no bug because platform_pci device does not exist and can only be emulated by qemu under xen.

Hope this helps, if not I can clarify more.