diff options
Diffstat (limited to 'drivers/xen/xenbus/xenbus_xs.c')
| -rw-r--r-- | drivers/xen/xenbus/xenbus_xs.c | 134 |
1 files changed, 107 insertions, 27 deletions
diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c index 5534690075a..ba804f3d827 100644 --- a/drivers/xen/xenbus/xenbus_xs.c +++ b/drivers/xen/xenbus/xenbus_xs.c @@ -31,6 +31,8 @@ * IN THE SOFTWARE. */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + #include <linux/unistd.h> #include <linux/errno.h> #include <linux/types.h> @@ -44,8 +46,11 @@ #include <linux/rwsem.h> #include <linux/module.h> #include <linux/mutex.h> +#include <asm/xen/hypervisor.h> #include <xen/xenbus.h> +#include <xen/xen.h> #include "xenbus_comms.h" +#include "xenbus_probe.h" struct xs_stored_msg { struct list_head list; @@ -127,15 +132,37 @@ static int get_error(const char *errorstring) for (i = 0; strcmp(errorstring, xsd_errors[i].errstring) != 0; i++) { if (i == ARRAY_SIZE(xsd_errors) - 1) { - printk(KERN_WARNING - "XENBUS xen store gave: unknown error %s", - errorstring); + pr_warn("xen store gave: unknown error %s\n", + errorstring); return EINVAL; } } return xsd_errors[i].errnum; } +static bool xenbus_ok(void) +{ + switch (xen_store_domain_type) { + case XS_LOCAL: + switch (system_state) { + case SYSTEM_POWER_OFF: + case SYSTEM_RESTART: + case SYSTEM_HALT: + return false; + default: + break; + } + return true; + case XS_PV: + case XS_HVM: + /* FIXME: Could check that the remote domain is alive, + * but it is normally initial domain. */ + return true; + default: + break; + } + return false; +} static void *read_reply(enum xsd_sockmsg_type *type, unsigned int *len) { struct xs_stored_msg *msg; @@ -145,9 +172,20 @@ static void *read_reply(enum xsd_sockmsg_type *type, unsigned int *len) while (list_empty(&xs_state.reply_list)) { spin_unlock(&xs_state.reply_lock); - /* XXX FIXME: Avoid synchronous wait for response here. */ - wait_event(xs_state.reply_waitq, - !list_empty(&xs_state.reply_list)); + if (xenbus_ok()) + /* XXX FIXME: Avoid synchronous wait for response here. */ + wait_event_timeout(xs_state.reply_waitq, + !list_empty(&xs_state.reply_list), + msecs_to_jiffies(500)); + else { + /* + * If we are in the process of being shut-down there is + * no point of trying to contact XenBus - it is either + * killed (xenstored application) or the other domain + * has been killed or is unreachable. + */ + return ERR_PTR(-EIO); + } spin_lock(&xs_state.reply_lock); } @@ -212,6 +250,9 @@ void *xenbus_dev_request_and_reply(struct xsd_sockmsg *msg) mutex_unlock(&xs_state.request_mutex); + if (IS_ERR(ret)) + return ret; + if ((msg->type == XS_TRANSACTION_END) || ((req_msg.type == XS_TRANSACTION_START) && (msg->type == XS_ERROR))) @@ -270,10 +311,8 @@ static void *xs_talkv(struct xenbus_transaction t, } if (msg.type != type) { - if (printk_ratelimit()) - printk(KERN_WARNING - "XENBUS unexpected type [%d], expected [%d]\n", - msg.type, type); + pr_warn_ratelimited("unexpected type [%d], expected [%d]\n", + msg.type, type); kfree(ret); return ERR_PTR(-EINVAL); } @@ -531,21 +570,18 @@ int xenbus_printf(struct xenbus_transaction t, { va_list ap; int ret; -#define PRINTF_BUFFER_SIZE 4096 - char *printf_buffer; - - printf_buffer = kmalloc(PRINTF_BUFFER_SIZE, GFP_NOIO | __GFP_HIGH); - if (printf_buffer == NULL) - return -ENOMEM; + char *buf; va_start(ap, fmt); - ret = vsnprintf(printf_buffer, PRINTF_BUFFER_SIZE, fmt, ap); + buf = kvasprintf(GFP_NOIO | __GFP_HIGH, fmt, ap); va_end(ap); - BUG_ON(ret > PRINTF_BUFFER_SIZE-1); - ret = xenbus_write(t, dir, node, printf_buffer); + if (!buf) + return -ENOMEM; + + ret = xenbus_write(t, dir, node, buf); - kfree(printf_buffer); + kfree(buf); return ret; } @@ -619,6 +655,45 @@ static struct xenbus_watch *find_watch(const char *token) return NULL; } +/* + * Certain older XenBus toolstack cannot handle reading values that are + * not populated. Some Xen 3.4 installation are incapable of doing this + * so if we are running on anything older than 4 do not attempt to read + * control/platform-feature-xs_reset_watches. + */ +static bool xen_strict_xenbus_quirk(void) +{ +#ifdef CONFIG_X86 + uint32_t eax, ebx, ecx, edx, base; + + base = xen_cpuid_base(); + cpuid(base + 1, &eax, &ebx, &ecx, &edx); + + if ((eax >> 16) < 4) + return true; +#endif + return false; + +} +static void xs_reset_watches(void) +{ + int err, supported = 0; + + if (!xen_hvm_domain() || xen_initial_domain()) + return; + + if (xen_strict_xenbus_quirk()) + return; + + err = xenbus_scanf(XBT_NIL, "control", + "platform-feature-xs_reset_watches", "%d", &supported); + if (err != 1 || !supported) + return; + + err = xs_error(xs_single(XBT_NIL, XS_RESET_WATCHES, "", NULL)); + if (err && err != -EEXIST) + pr_warn("xs_reset_watches failed: %d\n", err); +} /* Register callback to watch this node. */ int register_xenbus_watch(struct xenbus_watch *watch) @@ -638,8 +713,7 @@ int register_xenbus_watch(struct xenbus_watch *watch) err = xs_watch(watch->node, token); - /* Ignore errors due to multiple registration. */ - if ((err != 0) && (err != -EEXIST)) { + if (err) { spin_lock(&watches_lock); list_del(&watch->list); spin_unlock(&watches_lock); @@ -668,9 +742,7 @@ void unregister_xenbus_watch(struct xenbus_watch *watch) err = xs_unwatch(watch->node, token); if (err) - printk(KERN_WARNING - "XENBUS Failed to release watch %s: %i\n", - watch->node, err); + pr_warn("Failed to release watch %s: %i\n", watch->node, err); up_read(&xs_state.watch_mutex); @@ -801,6 +873,12 @@ static int process_msg(void) goto out; } + if (msg->hdr.len > XENSTORE_PAYLOAD_MAX) { + kfree(msg); + err = -EINVAL; + goto out; + } + body = kmalloc(msg->hdr.len + 1, GFP_NOIO | __GFP_HIGH); if (body == NULL) { kfree(msg); @@ -858,8 +936,7 @@ static int xenbus_thread(void *unused) for (;;) { err = process_msg(); if (err) - printk(KERN_WARNING "XENBUS error %d while reading " - "message\n", err); + pr_warn("error %d while reading message\n", err); if (kthread_should_stop()) break; } @@ -897,5 +974,8 @@ int xs_init(void) if (IS_ERR(task)) return PTR_ERR(task); + /* shutdown watches for kexec boot */ + xs_reset_watches(); + return 0; } |