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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [DOCDAY PATCH] docs: document/mark-up SCHEDOP_*
On Mon, 2012-07-30 at 10:42 +0100, Ian Campbell wrote:
> The biggest subtlety here is there additional argument when op ==
> SCHEDOP_shutdown and reason == SHUTDOWN_suspend and its interpretation by
> xc_domain_{save,restore}. Add some clarifying comments to libxc as well.
>
> Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
Any thoughts on this doc patch>
> ---
> tools/libxc/xc_domain_restore.c | 10 ++++-
> tools/libxc/xc_domain_save.c | 9 ++++-
> xen/include/public/sched.h | 84
> ++++++++++++++++++++++++++-------------
> 3 files changed, 72 insertions(+), 31 deletions(-)
>
> diff --git a/tools/libxc/xc_domain_restore.c b/tools/libxc/xc_domain_restore.c
> index 3fe2b12..5541e73 100644
> --- a/tools/libxc/xc_domain_restore.c
> +++ b/tools/libxc/xc_domain_restore.c
> @@ -1895,8 +1895,14 @@ int xc_domain_restore(xc_interface *xch, int io_fd,
> uint32_t dom,
> if ( i == 0 )
> {
> /*
> - * Uncanonicalise the suspend-record frame number and poke
> - * resume record.
> + * Uncanonicalise the start info frame number and poke in
> + * updated values into the start info itself.
> + *
> + * The start info MFN is the 3rd argument to the
> + * HYPERVISOR_sched_op hypercall when op==SCHEDOP_shutdown
> + * and reason==SHUTDOWN_suspend, it is canonicalised in
> + * xc_domain_save and therefore the PFN is found in the
> + * edx register.
> */
> pfn = GET_FIELD(ctxt, user_regs.edx);
> if ( (pfn >= dinfo->p2m_size) ||
> diff --git a/tools/libxc/xc_domain_save.c b/tools/libxc/xc_domain_save.c
> index c359649..f161472 100644
> --- a/tools/libxc/xc_domain_save.c
> +++ b/tools/libxc/xc_domain_save.c
> @@ -1867,7 +1867,14 @@ int xc_domain_save(xc_interface *xch, int io_fd,
> uint32_t dom, uint32_t max_iter
> goto out;
> }
>
> - /* Canonicalise the suspend-record frame number. */
> + /*
> + * Canonicalise the start info frame number.
> + *
> + * The start info MFN is the 3rd argument to the
> + * HYPERVISOR_sched_op hypercall when op==SCHEDOP_shutdown and
> + * reason==SHUTDOWN_suspend and is therefore found in the edx
> + * register.
> + */
> mfn = GET_FIELD(&ctxt, user_regs.edx);
> if ( !MFN_IS_IN_PSEUDOPHYS_MAP(mfn) )
> {
> diff --git a/xen/include/public/sched.h b/xen/include/public/sched.h
> index 7f87420..db5124a 100644
> --- a/xen/include/public/sched.h
> +++ b/xen/include/public/sched.h
> @@ -1,8 +1,8 @@
>
> /******************************************************************************
> * sched.h
> - *
> + *
> * Scheduler state interactions
> - *
> + *
> * Permission is hereby granted, free of charge, to any person obtaining a
> copy
> * of this software and associated documentation files (the "Software"), to
> * deal in the Software without restriction, including without limitation the
> @@ -30,20 +30,33 @@
> #include "event_channel.h"
>
> /*
> + * `incontents 150 sched Guest Scheduler Operations
> + *
> + * The SCHEDOP interface provides mechanisms for a guest to interact
> + * with the scheduler, including yield, blocking and shutting itself
> + * down.
> + */
> +
> +/*
> * The prototype for this hypercall is:
> - * long sched_op(int cmd, void *arg)
> + * ` long HYPERVISOR_sched_op(enum sched_op cmd, void *arg, ...)
> + *
> * @cmd == SCHEDOP_??? (scheduler operation).
> * @arg == Operation-specific extra argument(s), as described below.
> - *
> + * ... == Additional Operation-specific extra arguments, described below.
> + *
> * Versions of Xen prior to 3.0.2 provided only the following legacy version
> * of this hypercall, supporting only the commands yield, block and shutdown:
> * long sched_op(int cmd, unsigned long arg)
> * @cmd == SCHEDOP_??? (scheduler operation).
> * @arg == 0 (SCHEDOP_yield and SCHEDOP_block)
> * == SHUTDOWN_* code (SCHEDOP_shutdown)
> - * This legacy version is available to new guests as sched_op_compat().
> + *
> + * This legacy version is available to new guests as:
> + * ` long HYPERVISOR_sched_op_compat(enum sched_op cmd, unsigned long arg)
> */
>
> +/* ` enum sched_op { // SCHEDOP_* => struct sched_* */
> /*
> * Voluntarily yield the CPU.
> * @arg == NULL.
> @@ -61,59 +74,72 @@
>
> /*
> * Halt execution of this domain (all VCPUs) and notify the system
> controller.
> - * @arg == pointer to sched_shutdown structure.
> + * @arg == pointer to sched_shutdown_t structure.
> + *
> + * If the sched_shutdown_t reason is SHUTDOWN_suspend then this
> + * hypercall takes an additional extra argument which should be the
> + * MFN of the guest's start_info_t.
> + *
> + * In addition, which reason is SHUTDOWN_suspend this hypercall
> + * returns 1 if suspend was cancelled or the domain was merely
> + * checkpointed, and 0 if it is resuming in a new domain.
> */
> #define SCHEDOP_shutdown 2
> -struct sched_shutdown {
> - unsigned int reason; /* SHUTDOWN_* */
> -};
> -typedef struct sched_shutdown sched_shutdown_t;
> -DEFINE_XEN_GUEST_HANDLE(sched_shutdown_t);
>
> /*
> * Poll a set of event-channel ports. Return when one or more are pending. An
> * optional timeout may be specified.
> - * @arg == pointer to sched_poll structure.
> + * @arg == pointer to sched_poll_t structure.
> */
> #define SCHEDOP_poll 3
> -struct sched_poll {
> - XEN_GUEST_HANDLE(evtchn_port_t) ports;
> - unsigned int nr_ports;
> - uint64_t timeout;
> -};
> -typedef struct sched_poll sched_poll_t;
> -DEFINE_XEN_GUEST_HANDLE(sched_poll_t);
>
> /*
> * Declare a shutdown for another domain. The main use of this function is
> * in interpreting shutdown requests and reasons for fully-virtualized
> * domains. A para-virtualized domain may use SCHEDOP_shutdown directly.
> - * @arg == pointer to sched_remote_shutdown structure.
> + * @arg == pointer to sched_remote_shutdown_t structure.
> */
> #define SCHEDOP_remote_shutdown 4
> -struct sched_remote_shutdown {
> - domid_t domain_id; /* Remote domain ID */
> - unsigned int reason; /* SHUTDOWN_xxx reason */
> -};
> -typedef struct sched_remote_shutdown sched_remote_shutdown_t;
> -DEFINE_XEN_GUEST_HANDLE(sched_remote_shutdown_t);
>
> /*
> * Latch a shutdown code, so that when the domain later shuts down it
> * reports this code to the control tools.
> - * @arg == as for SCHEDOP_shutdown.
> + * @arg == sched_shutdown_t, as for SCHEDOP_shutdown.
> */
> #define SCHEDOP_shutdown_code 5
>
> /*
> * Setup, poke and destroy a domain watchdog timer.
> - * @arg == pointer to sched_watchdog structure.
> + * @arg == pointer to sched_watchdog_t structure.
> * With id == 0, setup a domain watchdog timer to cause domain shutdown
> * after timeout, returns watchdog id.
> * With id != 0 and timeout == 0, destroy domain watchdog timer.
> * With id != 0 and timeout != 0, poke watchdog timer and set new timeout.
> */
> #define SCHEDOP_watchdog 6
> +/* ` } */
> +
> +struct sched_shutdown {
> + unsigned int reason; /* SHUTDOWN_* => enum sched_shutdown_reason */
> +};
> +typedef struct sched_shutdown sched_shutdown_t;
> +DEFINE_XEN_GUEST_HANDLE(sched_shutdown_t);
> +
> +struct sched_poll {
> + XEN_GUEST_HANDLE(evtchn_port_t) ports;
> + unsigned int nr_ports;
> + uint64_t timeout;
> +};
> +typedef struct sched_poll sched_poll_t;
> +DEFINE_XEN_GUEST_HANDLE(sched_poll_t);
> +
> +struct sched_remote_shutdown {
> + domid_t domain_id; /* Remote domain ID */
> + unsigned int reason; /* SHUTDOWN_* => enum sched_shutdown_reason */
> +};
> +typedef struct sched_remote_shutdown sched_remote_shutdown_t;
> +DEFINE_XEN_GUEST_HANDLE(sched_remote_shutdown_t);
> +
> struct sched_watchdog {
> uint32_t id; /* watchdog ID */
> uint32_t timeout; /* timeout */
> @@ -126,11 +152,13 @@ DEFINE_XEN_GUEST_HANDLE(sched_watchdog_t);
> * software to determine the appropriate action. For the most part, Xen does
> * not care about the shutdown code.
> */
> +/* ` enum sched_shutdown_reason { */
> #define SHUTDOWN_poweroff 0 /* Domain exited normally. Clean up and kill.
> */
> #define SHUTDOWN_reboot 1 /* Clean up, kill, and then restart.
> */
> #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.
> */
> +/* ` } */
>
> #endif /* __XEN_PUBLIC_SCHED_H__ */
>
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