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authorVitaly Kuznetsov <vkuznets@redhat.com>2015-09-25 11:59:52 +0200
committerDavid Vrabel <david.vrabel@citrix.com>2015-09-28 14:48:52 +0100
commit0b34a166f291d255755be46e43ed5497cdd194f2 (patch)
tree5b7a2348190f566b74b3de41af90240887773529 /include/xen
parent2ecf91b6d8b0ee8ef38aa7ea2a0fe0cd57b6ca50 (diff)
x86/xen: Support kexec/kdump in HVM guests by doing a soft reset
Currently there is a number of issues preventing PVHVM Xen guests from doing successful kexec/kdump: - Bound event channels. - Registered vcpu_info. - PIRQ/emuirq mappings. - shared_info frame after XENMAPSPACE_shared_info operation. - Active grant mappings. Basically, newly booted kernel stumbles upon already set up Xen interfaces and there is no way to reestablish them. In Xen-4.7 a new feature called 'soft reset' is coming. A guest performing kexec/kdump operation is supposed to call SCHEDOP_shutdown hypercall with SHUTDOWN_soft_reset reason before jumping to new kernel. Hypervisor (with some help from toolstack) will do full domain cleanup (but keeping its memory and vCPU contexts intact) returning the guest to the state it had when it was first booted and thus allowing it to start over. Doing SHUTDOWN_soft_reset on Xen hypervisors which don't support it is probably OK as by default all unknown shutdown reasons cause domain destroy with a message in toolstack log: 'Unknown shutdown reason code 5. Destroying domain.' which gives a clue to what the problem is and eliminates false expectations. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Diffstat (limited to 'include/xen')
-rw-r--r--include/xen/interface/sched.h8
1 files changed, 8 insertions, 0 deletions
diff --git a/include/xen/interface/sched.h b/include/xen/interface/sched.h
index 9ce083960a25..f18490985fc8 100644
--- a/include/xen/interface/sched.h
+++ b/include/xen/interface/sched.h
@@ -107,5 +107,13 @@ struct sched_watchdog {
#define SHUTDOWN_suspend 2 /* Clean up, save suspend info, kill. */
#define SHUTDOWN_crash 3 /* Tell controller we've crashed. */
#define SHUTDOWN_watchdog 4 /* Restart because watchdog time expired. */
+/*
+ * Domain asked to perform 'soft reset' for it. The expected behavior is to
+ * reset internal Xen state for the domain returning it to the point where it
+ * was created but leaving the domain's memory contents and vCPU contexts
+ * intact. This will allow the domain to start over and set up all Xen specific
+ * interfaces again.
+ */
+#define SHUTDOWN_soft_reset 5
#endif /* __XEN_PUBLIC_SCHED_H__ */

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