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0b34a166f2
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>
119 lines
4 KiB
C
119 lines
4 KiB
C
/******************************************************************************
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* sched.h
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*
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* Scheduler state interactions
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*
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* Copyright (c) 2005, Keir Fraser <keir@xensource.com>
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*/
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#ifndef __XEN_PUBLIC_SCHED_H__
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#define __XEN_PUBLIC_SCHED_H__
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#include <xen/interface/event_channel.h>
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/*
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* The prototype for this hypercall is:
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* long sched_op_new(int cmd, void *arg)
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* @cmd == SCHEDOP_??? (scheduler operation).
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* @arg == Operation-specific extra argument(s), as described below.
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*
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* **NOTE**:
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* Versions of Xen prior to 3.0.2 provide only the following legacy version
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* of this hypercall, supporting only the commands yield, block and shutdown:
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* long sched_op(int cmd, unsigned long arg)
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* @cmd == SCHEDOP_??? (scheduler operation).
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* @arg == 0 (SCHEDOP_yield and SCHEDOP_block)
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* == SHUTDOWN_* code (SCHEDOP_shutdown)
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*/
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/*
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* Voluntarily yield the CPU.
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* @arg == NULL.
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*/
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#define SCHEDOP_yield 0
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/*
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* Block execution of this VCPU until an event is received for processing.
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* If called with event upcalls masked, this operation will atomically
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* reenable event delivery and check for pending events before blocking the
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* VCPU. This avoids a "wakeup waiting" race.
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* @arg == NULL.
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*/
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#define SCHEDOP_block 1
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/*
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* Halt execution of this domain (all VCPUs) and notify the system controller.
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* @arg == pointer to sched_shutdown structure.
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*/
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#define SCHEDOP_shutdown 2
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struct sched_shutdown {
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unsigned int reason; /* SHUTDOWN_* */
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};
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DEFINE_GUEST_HANDLE_STRUCT(sched_shutdown);
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/*
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* Poll a set of event-channel ports. Return when one or more are pending. An
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* optional timeout may be specified.
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* @arg == pointer to sched_poll structure.
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*/
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#define SCHEDOP_poll 3
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struct sched_poll {
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GUEST_HANDLE(evtchn_port_t) ports;
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unsigned int nr_ports;
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uint64_t timeout;
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};
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DEFINE_GUEST_HANDLE_STRUCT(sched_poll);
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/*
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* Declare a shutdown for another domain. The main use of this function is
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* in interpreting shutdown requests and reasons for fully-virtualized
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* domains. A para-virtualized domain may use SCHEDOP_shutdown directly.
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* @arg == pointer to sched_remote_shutdown structure.
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*/
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#define SCHEDOP_remote_shutdown 4
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struct sched_remote_shutdown {
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domid_t domain_id; /* Remote domain ID */
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unsigned int reason; /* SHUTDOWN_xxx reason */
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};
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/*
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* Latch a shutdown code, so that when the domain later shuts down it
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* reports this code to the control tools.
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* @arg == as for SCHEDOP_shutdown.
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*/
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#define SCHEDOP_shutdown_code 5
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/*
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* Setup, poke and destroy a domain watchdog timer.
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* @arg == pointer to sched_watchdog structure.
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* With id == 0, setup a domain watchdog timer to cause domain shutdown
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* after timeout, returns watchdog id.
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* With id != 0 and timeout == 0, destroy domain watchdog timer.
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* With id != 0 and timeout != 0, poke watchdog timer and set new timeout.
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*/
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#define SCHEDOP_watchdog 6
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struct sched_watchdog {
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uint32_t id; /* watchdog ID */
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uint32_t timeout; /* timeout */
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};
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/*
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* Reason codes for SCHEDOP_shutdown. These may be interpreted by control
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* software to determine the appropriate action. For the most part, Xen does
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* not care about the shutdown code.
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*/
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#define SHUTDOWN_poweroff 0 /* Domain exited normally. Clean up and kill. */
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#define SHUTDOWN_reboot 1 /* Clean up, kill, and then restart. */
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#define SHUTDOWN_suspend 2 /* Clean up, save suspend info, kill. */
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#define SHUTDOWN_crash 3 /* Tell controller we've crashed. */
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#define SHUTDOWN_watchdog 4 /* Restart because watchdog time expired. */
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/*
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* Domain asked to perform 'soft reset' for it. The expected behavior is to
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* reset internal Xen state for the domain returning it to the point where it
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* was created but leaving the domain's memory contents and vCPU contexts
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* intact. This will allow the domain to start over and set up all Xen specific
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* interfaces again.
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*/
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#define SHUTDOWN_soft_reset 5
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#endif /* __XEN_PUBLIC_SCHED_H__ */
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