From 0e91398f2a5d4eb6b07df8115917d0d1cf3e9b58 Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Mon, 26 May 2008 23:31:27 +0100 Subject: xen: implement save/restore This patch implements Xen save/restore and migration. Saving is triggered via xenbus, which is polled in drivers/xen/manage.c. When a suspend request comes in, the kernel prepares itself for saving by: 1 - Freeze all processes. This is primarily to prevent any partially-completed pagetable updates from confusing the suspend process. If CONFIG_PREEMPT isn't defined, then this isn't necessary. 2 - Suspend xenbus and other devices 3 - Stop_machine, to make sure all the other vcpus are quiescent. The Xen tools require the domain to run its save off vcpu0. 4 - Within the stop_machine state, it pins any unpinned pgds (under construction or destruction), performs canonicalizes various other pieces of state (mostly converting mfns to pfns), and finally 5 - Suspend the domain Restore reverses the steps used to save the domain, ending when all the frozen processes are thawed. Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Thomas Gleixner --- drivers/xen/events.c | 83 ++++++++++++++++++++++++++++++ drivers/xen/grant-table.c | 4 +- drivers/xen/manage.c | 126 ++++++++++++++++++++++++++++++++++++++++------ 3 files changed, 197 insertions(+), 16 deletions(-) (limited to 'drivers/xen') diff --git a/drivers/xen/events.c b/drivers/xen/events.c index 70375a69076..73d78dc9b87 100644 --- a/drivers/xen/events.c +++ b/drivers/xen/events.c @@ -674,6 +674,89 @@ static int retrigger_dynirq(unsigned int irq) return ret; } +static void restore_cpu_virqs(unsigned int cpu) +{ + struct evtchn_bind_virq bind_virq; + int virq, irq, evtchn; + + for (virq = 0; virq < NR_VIRQS; virq++) { + if ((irq = per_cpu(virq_to_irq, cpu)[virq]) == -1) + continue; + + BUG_ON(irq_info[irq].type != IRQT_VIRQ); + BUG_ON(irq_info[irq].index != virq); + + /* Get a new binding from Xen. */ + bind_virq.virq = virq; + bind_virq.vcpu = cpu; + if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq, + &bind_virq) != 0) + BUG(); + evtchn = bind_virq.port; + + /* Record the new mapping. */ + evtchn_to_irq[evtchn] = irq; + irq_info[irq] = mk_irq_info(IRQT_VIRQ, virq, evtchn); + bind_evtchn_to_cpu(evtchn, cpu); + + /* Ready for use. */ + unmask_evtchn(evtchn); + } +} + +static void restore_cpu_ipis(unsigned int cpu) +{ + struct evtchn_bind_ipi bind_ipi; + int ipi, irq, evtchn; + + for (ipi = 0; ipi < XEN_NR_IPIS; ipi++) { + if ((irq = per_cpu(ipi_to_irq, cpu)[ipi]) == -1) + continue; + + BUG_ON(irq_info[irq].type != IRQT_IPI); + BUG_ON(irq_info[irq].index != ipi); + + /* Get a new binding from Xen. */ + bind_ipi.vcpu = cpu; + if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi, + &bind_ipi) != 0) + BUG(); + evtchn = bind_ipi.port; + + /* Record the new mapping. */ + evtchn_to_irq[evtchn] = irq; + irq_info[irq] = mk_irq_info(IRQT_IPI, ipi, evtchn); + bind_evtchn_to_cpu(evtchn, cpu); + + /* Ready for use. */ + unmask_evtchn(evtchn); + + } +} + +void xen_irq_resume(void) +{ + unsigned int cpu, irq, evtchn; + + init_evtchn_cpu_bindings(); + + /* New event-channel space is not 'live' yet. */ + for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++) + mask_evtchn(evtchn); + + /* No IRQ <-> event-channel mappings. */ + for (irq = 0; irq < NR_IRQS; irq++) + irq_info[irq].evtchn = 0; /* zap event-channel binding */ + + for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++) + evtchn_to_irq[evtchn] = -1; + + for_each_possible_cpu(cpu) { + restore_cpu_virqs(cpu); + restore_cpu_ipis(cpu); + } +} + static struct irq_chip xen_dynamic_chip __read_mostly = { .name = "xen-dyn", .mask = disable_dynirq, diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c index 52b6b41b909..e9e11168616 100644 --- a/drivers/xen/grant-table.c +++ b/drivers/xen/grant-table.c @@ -471,14 +471,14 @@ static int gnttab_map(unsigned int start_idx, unsigned int end_idx) return 0; } -static int gnttab_resume(void) +int gnttab_resume(void) { if (max_nr_grant_frames() < nr_grant_frames) return -ENOSYS; return gnttab_map(0, nr_grant_frames - 1); } -static int gnttab_suspend(void) +int gnttab_suspend(void) { arch_gnttab_unmap_shared(shared, nr_grant_frames); return 0; diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c index aa7af9e6abc..ba85fa2cff3 100644 --- a/drivers/xen/manage.c +++ b/drivers/xen/manage.c @@ -5,21 +5,113 @@ #include #include #include +#include +#include #include - -#define SHUTDOWN_INVALID -1 -#define SHUTDOWN_POWEROFF 0 -#define SHUTDOWN_SUSPEND 2 -/* Code 3 is SHUTDOWN_CRASH, which we don't use because the domain can only - * report a crash, not be instructed to crash! - * HALT is the same as POWEROFF, as far as we're concerned. The tools use - * the distinction when we return the reason code to them. - */ -#define SHUTDOWN_HALT 4 +#include +#include +#include +#include + +#include +#include + +enum shutdown_state { + SHUTDOWN_INVALID = -1, + SHUTDOWN_POWEROFF = 0, + SHUTDOWN_SUSPEND = 2, + /* Code 3 is SHUTDOWN_CRASH, which we don't use because the domain can only + report a crash, not be instructed to crash! + HALT is the same as POWEROFF, as far as we're concerned. The tools use + the distinction when we return the reason code to them. */ + SHUTDOWN_HALT = 4, +}; /* Ignore multiple shutdown requests. */ -static int shutting_down = SHUTDOWN_INVALID; +static enum shutdown_state shutting_down = SHUTDOWN_INVALID; + +static int xen_suspend(void *data) +{ + int *cancelled = data; + + BUG_ON(!irqs_disabled()); + + load_cr3(swapper_pg_dir); + + xen_mm_pin_all(); + gnttab_suspend(); + xen_time_suspend(); + xen_pre_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. + */ + *cancelled = HYPERVISOR_suspend(virt_to_mfn(xen_start_info)); + + xen_post_suspend(*cancelled); + xen_time_resume(); + gnttab_resume(); + xen_mm_unpin_all(); + + if (!*cancelled) { + xen_irq_resume(); + xen_console_resume(); + } + + return 0; +} + +static void do_suspend(void) +{ + int err; + int cancelled = 1; + + shutting_down = SHUTDOWN_SUSPEND; + +#ifdef CONFIG_PREEMPT + /* If the kernel is preemptible, we need to freeze all the processes + to prevent them from being in the middle of a pagetable update + during suspend. */ + err = freeze_processes(); + if (err) { + printk(KERN_ERR "xen suspend: freeze failed %d\n", err); + return; + } +#endif + + err = device_suspend(PMSG_SUSPEND); + if (err) { + printk(KERN_ERR "xen suspend: device_suspend %d\n", err); + goto out; + } + + printk("suspending xenbus...\n"); + /* XXX use normal device tree? */ + xenbus_suspend(); + + err = stop_machine_run(xen_suspend, &cancelled, 0); + if (err) { + printk(KERN_ERR "failed to start xen_suspend: %d\n", err); + goto out; + } + + if (!cancelled) + xenbus_resume(); + else + xenbus_suspend_cancel(); + + device_resume(); + + +out: +#ifdef CONFIG_PREEMPT + thaw_processes(); +#endif + shutting_down = SHUTDOWN_INVALID; +} static void shutdown_handler(struct xenbus_watch *watch, const char **vec, unsigned int len) @@ -52,11 +144,17 @@ static void shutdown_handler(struct xenbus_watch *watch, } if (strcmp(str, "poweroff") == 0 || - strcmp(str, "halt") == 0) + strcmp(str, "halt") == 0) { + shutting_down = SHUTDOWN_POWEROFF; orderly_poweroff(false); - else if (strcmp(str, "reboot") == 0) + } else if (strcmp(str, "reboot") == 0) { + shutting_down = SHUTDOWN_POWEROFF; /* ? */ ctrl_alt_del(); - else { +#ifdef CONFIG_PM_SLEEP + } else if (strcmp(str, "suspend") == 0) { + do_suspend(); +#endif + } else { printk(KERN_INFO "Ignoring shutdown request: %s\n", str); shutting_down = SHUTDOWN_INVALID; } -- cgit v1.2.3