diff options
Diffstat (limited to 'drivers/xen/xenbus/xenbus_probe.c')
-rw-r--r-- | drivers/xen/xenbus/xenbus_probe.c | 138 |
1 files changed, 124 insertions, 14 deletions
diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c index 5b471889d723..b911a91bce6b 100644 --- a/drivers/xen/xenbus/xenbus_probe.c +++ b/drivers/xen/xenbus/xenbus_probe.c @@ -136,6 +136,7 @@ static int watch_otherend(struct xenbus_device *dev) container_of(dev->dev.bus, struct xen_bus_type, bus); return xenbus_watch_pathfmt(dev, &dev->otherend_watch, + bus->otherend_will_handle, bus->otherend_changed, "%s/%s", dev->otherend, "state"); } @@ -682,29 +683,107 @@ void unregister_xenstore_notifier(struct notifier_block *nb) } EXPORT_SYMBOL_GPL(unregister_xenstore_notifier); -void xenbus_probe(struct work_struct *unused) +static void xenbus_probe(void) { xenstored_ready = 1; + /* + * In the HVM case, xenbus_init() deferred its call to + * xs_init() in case callbacks were not operational yet. + * So do it now. + */ + if (xen_store_domain_type == XS_HVM) + xs_init(); + /* Notify others that xenstore is up */ blocking_notifier_call_chain(&xenstore_chain, 0, NULL); } -EXPORT_SYMBOL_GPL(xenbus_probe); -static int __init xenbus_probe_initcall(void) +/* + * Returns true when XenStore init must be deferred in order to + * allow the PCI platform device to be initialised, before we + * can actually have event channel interrupts working. + */ +static bool xs_hvm_defer_init_for_callback(void) { - if (!xen_domain()) - return -ENODEV; +#ifdef CONFIG_XEN_PVHVM + return xen_store_domain_type == XS_HVM && + !xen_have_vector_callback; +#else + return false; +#endif +} - if (xen_initial_domain() || xen_hvm_domain()) - return 0; +static int xenbus_probe_thread(void *unused) +{ + DEFINE_WAIT(w); - xenbus_probe(NULL); + /* + * We actually just want to wait for *any* trigger of xb_waitq, + * and run xenbus_probe() the moment it occurs. + */ + prepare_to_wait(&xb_waitq, &w, TASK_INTERRUPTIBLE); + schedule(); + finish_wait(&xb_waitq, &w); + + DPRINTK("probing"); + xenbus_probe(); return 0; } +static int __init xenbus_probe_initcall(void) +{ + /* + * Probe XenBus here in the XS_PV case, and also XS_HVM unless we + * need to wait for the platform PCI device to come up. + */ + if (xen_store_domain_type == XS_PV || + (xen_store_domain_type == XS_HVM && + !xs_hvm_defer_init_for_callback())) + xenbus_probe(); + + /* + * For XS_LOCAL, spawn a thread which will wait for xenstored + * or a xenstore-stubdom to be started, then probe. It will be + * triggered when communication starts happening, by waiting + * on xb_waitq. + */ + if (xen_store_domain_type == XS_LOCAL) { + struct task_struct *probe_task; + + probe_task = kthread_run(xenbus_probe_thread, NULL, + "xenbus_probe"); + if (IS_ERR(probe_task)) + return PTR_ERR(probe_task); + } + return 0; +} device_initcall(xenbus_probe_initcall); +int xen_set_callback_via(uint64_t via) +{ + struct xen_hvm_param a; + int ret; + + a.domid = DOMID_SELF; + a.index = HVM_PARAM_CALLBACK_IRQ; + a.value = via; + + ret = HYPERVISOR_hvm_op(HVMOP_set_param, &a); + if (ret) + return ret; + + /* + * If xenbus_probe_initcall() deferred the xenbus_probe() + * due to the callback not functioning yet, we can do it now. + */ + if (!xenstored_ready && xs_hvm_defer_init_for_callback()) + xenbus_probe(); + + return ret; +} +EXPORT_SYMBOL_GPL(xen_set_callback_via); + /* Set up event channel for xenstored which is run as a local process * (this is normally used only in dom0) */ @@ -767,7 +846,7 @@ static struct notifier_block xenbus_resume_nb = { static int __init xenbus_init(void) { - int err = 0; + int err; uint64_t v = 0; xen_store_domain_type = XS_UNKNOWN; @@ -807,6 +886,29 @@ static int __init xenbus_init(void) err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v); if (err) goto out_error; + /* + * Uninitialized hvm_params are zero and return no error. + * Although it is theoretically possible to have + * HVM_PARAM_STORE_PFN set to zero on purpose, in reality it is + * not zero when valid. If zero, it means that Xenstore hasn't + * been properly initialized. Instead of attempting to map a + * wrong guest physical address return error. + * + * Also recognize all bits set as an invalid value. + */ + if (!v || !~v) { + err = -ENOENT; + goto out_error; + } + /* Avoid truncation on 32-bit. */ +#if BITS_PER_LONG == 32 + if (v > ULONG_MAX) { + pr_err("%s: cannot handle HVM_PARAM_STORE_PFN=%llx > ULONG_MAX\n", + __func__, v); + err = -EINVAL; + goto out_error; + } +#endif xen_store_gfn = (unsigned long)v; xen_store_interface = xen_remap(xen_store_gfn << XEN_PAGE_SHIFT, @@ -817,11 +919,17 @@ static int __init xenbus_init(void) break; } - /* Initialize the interface to xenstore. */ - err = xs_init(); - if (err) { - pr_warn("Error initializing xenstore comms: %i\n", err); - goto out_error; + /* + * HVM domains may not have a functional callback yet. In that + * case let xs_init() be called from xenbus_probe(), which will + * get invoked at an appropriate time. + */ + if (xen_store_domain_type != XS_HVM) { + err = xs_init(); + if (err) { + pr_warn("Error initializing xenstore comms: %i\n", err); + goto out_error; + } } if ((xen_store_domain_type != XS_LOCAL) && @@ -835,8 +943,10 @@ static int __init xenbus_init(void) */ proc_create_mount_point("xen"); #endif + return 0; out_error: + xen_store_domain_type = XS_UNKNOWN; return err; } |