Konrad Rzeszutek Wilk cb6b6df111 xen/pv-on-hvm kexec: add quirk for Xen 3.4 and shutdown watches. ... The commit 254d1a3f02, titled "xen/pv-on-hvm kexec: shutdown watches from old kernel" assumes that the XenBus backend can deal with reading of values from: "control/platform-feature-xs_reset_watches": ... a patch for xenstored is required so that it accepts the XS_RESET_WATCHES request from a client (see changeset 23839:42a45baf037d in xen-unstable.hg). Without the patch for xenstored the registration of watches will fail and some features of a PVonHVM guest are not available. The guest is still able to boot, but repeated kexec boots will fail." Sadly this is not true when using a Xen 3.4 hypervisor and booting a PVHVM guest. We end up hanging at: err = xenbus_scanf(XBT_NIL, "control", "platform-feature-xs_reset_watches", "%d", &supported); This can easily be seen with guests hanging at xenbus_init: NX (Execute Disable) protection: active SMBIOS 2.4 present. DMI: Xen HVM domU, BIOS 3.4.0 05/13/2011 Hypervisor detected: Xen HVM Xen version 3.4. Xen Platform PCI: I/O protocol version 1 ... snip .. calling xenbus_init+0x0/0x27e @ 1 Reverting the commit or using the attached patch fixes the issue. This fix checks whether the hypervisor is older than 4.0 and if so does not try to perform the read. Fixes-Oracle-Bug: 14708233 CC: stable@vger.kernel.org Acked-by: Olaf Hering <olaf@aepfle.de> [v2: Added a comment in the source code] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>		2012-10-12 08:49:21 -04:00
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Makefile	xen: Add xenbus_backend device	2011-12-16 13:29:41 -05:00
xenbus_client.c	xen/gndev: Xen backend support for paged out grant targets V4.	2012-09-21 09:23:51 -04:00
xenbus_comms.c	xen/arm: compile and run xenbus	2012-09-17 10:04:04 -04:00
xenbus_comms.h	xenbus: Add support for xenbus backend in stub domain	2012-05-21 09:53:18 -04:00
xenbus_dev_backend.c	xen/apic/xenbus/swiotlb/pcifront/grant/tmem: Make functions or variables static.	2012-08-21 14:50:03 -04:00
xenbus_dev_frontend.c	xenbus_dev: add missing error check to watch handling	2012-02-03 16:07:05 -05:00
xenbus_probe_backend.c	Xen: consolidate and simplify struct xenbus_driver instantiation	2012-01-04 17:01:17 -05:00
xenbus_probe_frontend.c	xen: missing includes	2012-08-21 14:49:21 -04:00
xenbus_probe.c	xen/arm: compile and run xenbus	2012-09-17 10:04:04 -04:00
xenbus_probe.h	Xen: consolidate and simplify struct xenbus_driver instantiation	2012-01-04 17:01:17 -05:00
xenbus_xs.c	xen/pv-on-hvm kexec: add quirk for Xen 3.4 and shutdown watches.	2012-10-12 08:49:21 -04:00