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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [minios] Add xenbus shutdown control support
On Wed, 2012-11-28 at 21:57 +0000, Samuel Thibault wrote:
> Add a thread watching the xenbus shutdown control path and notifies a
> wait queue.
Why a wait queue rather than a weak function call?
> Add HYPERVISOR_shutdown convenient inline for minios shutdown.
>
> Add proper shutdown to the minios test application.
The use of locks in here is pretty exciting, with the up/downs being
spread over various places, but I think I've worked it out and it's only
a test app ;-)
> Signed-off-by: Samuel Thibault <samuel.thibault@xxxxxxxxxxxx>
>
> diff -r fdf241ea6ff4 extras/mini-os/include/kernel.h
> --- a/extras/mini-os/include/kernel.h Wed Nov 28 21:29:18 2012 +0100
> +++ b/extras/mini-os/include/kernel.h Wed Nov 28 22:53:42 2012 +0100
> @@ -1,6 +1,9 @@
> #ifndef _KERNEL_H_
> #define _KERNEL_H_
>
> +extern unsigned int do_shutdown;
> +extern unsigned int shutdown_reason;
> +extern struct wait_queue_head shutdown_queue;
> extern void do_exit(void) __attribute__((noreturn));
> extern void stop_kernel(void);
>
> diff -r fdf241ea6ff4 extras/mini-os/include/x86/x86_32/hypercall-x86_32.h
> --- a/extras/mini-os/include/x86/x86_32/hypercall-x86_32.h Wed Nov 28
> 21:29:18 2012 +0100
> +++ b/extras/mini-os/include/x86/x86_32/hypercall-x86_32.h Wed Nov 28
> 22:53:42 2012 +0100
> @@ -172,6 +172,14 @@
> return _hypercall2(int, sched_op, cmd, arg);
> }
>
> +static inline int
> +HYPERVISOR_shutdown(
> + unsigned int reason)
> +{
> + struct sched_shutdown shutdown = { .reason = reason };
> + return _hypercall2(int, sched_op, SCHEDOP_shutdown, &shutdown);
> +}
> +
> static inline long
> HYPERVISOR_set_timer_op(
> uint64_t timeout)
> diff -r fdf241ea6ff4 extras/mini-os/include/x86/x86_64/hypercall-x86_64.h
> --- a/extras/mini-os/include/x86/x86_64/hypercall-x86_64.h Wed Nov 28
> 21:29:18 2012 +0100
> +++ b/extras/mini-os/include/x86/x86_64/hypercall-x86_64.h Wed Nov 28
> 22:53:42 2012 +0100
> @@ -176,6 +176,14 @@
> return _hypercall2(int, sched_op, cmd, arg);
> }
>
> +static inline int
> +HYPERVISOR_shutdown(
> + unsigned int reason)
> +{
> + struct sched_shutdown shutdown = { .reason = reason };
> + return _hypercall2(int, sched_op, SCHEDOP_shutdown, &shutdown);
> +}
> +
> static inline long
> HYPERVISOR_set_timer_op(
> uint64_t timeout)
> diff -r fdf241ea6ff4 extras/mini-os/kernel.c
> --- a/extras/mini-os/kernel.c Wed Nov 28 21:29:18 2012 +0100
> +++ b/extras/mini-os/kernel.c Wed Nov 28 22:53:42 2012 +0100
> @@ -48,6 +48,10 @@
>
> uint8_t xen_features[XENFEAT_NR_SUBMAPS * 32];
>
> +unsigned int do_shutdown = 0;
> +unsigned int shutdown_reason;
> +DECLARE_WAIT_QUEUE_HEAD(shutdown_queue);
> +
> void setup_xen_features(void)
> {
> xen_feature_info_t fi;
> @@ -64,6 +68,36 @@
> }
> }
>
> +static void shutdown_thread(void *p)
> +{
> + const char *path = "control/shutdown";
> + const char *token = path;
> + xenbus_event_queue events = NULL;
> + char *shutdown, *err;
> + xenbus_watch_path_token(XBT_NIL, path, token, &events);
> + while ((err = xenbus_read(XBT_NIL, path, &shutdown)) != NULL)
> + {
> + free(err);
> + xenbus_wait_for_watch(&events);
> + }
> + xenbus_unwatch_path_token(XBT_NIL, path, token);
> + xenbus_write(XBT_NIL, path, "");
> + printk("Shutting down (%s)\n", shutdown);
> +
> + if (!strcmp(shutdown, "poweroff"))
> + shutdown_reason = SHUTDOWN_poweroff;
> + else if (!strcmp(shutdown, "reboot"))
> + shutdown_reason = SHUTDOWN_reboot;
> + else
> + /* Unknown */
> + shutdown_reason = SHUTDOWN_crash;
> + wmb();
> + do_shutdown = 1;
> + wmb();
> + wake_up(&shutdown_queue);
> +}
> +
> +
> /* This should be overridden by the application we are linked against. */
> __attribute__((weak)) int app_main(start_info_t *si)
> {
> @@ -126,6 +160,8 @@
> /* Init XenBus */
> init_xenbus();
>
> + create_thread("shutdown", shutdown_thread, NULL);
> +
> /* Call (possibly overridden) app_main() */
> app_main(&start_info);
>
> diff -r fdf241ea6ff4 extras/mini-os/test.c
> --- a/extras/mini-os/test.c Wed Nov 28 21:29:18 2012 +0100
> +++ b/extras/mini-os/test.c Wed Nov 28 22:53:42 2012 +0100
> @@ -46,6 +46,7 @@
> #include <xen/version.h>
>
> static struct netfront_dev *net_dev;
> +static struct semaphore net_sem = __SEMAPHORE_INITIALIZER(net_sem, 0);
>
> void test_xenbus(void);
>
> @@ -70,12 +71,14 @@
> static void netfront_thread(void *p)
> {
> net_dev = init_netfront(NULL, NULL, NULL, NULL);
> + up(&net_sem);
> }
>
> static struct blkfront_dev *blk_dev;
> static struct blkfront_info blk_info;
> static uint64_t blk_size_read;
> static uint64_t blk_size_write;
> +static struct semaphore blk_sem = __SEMAPHORE_INITIALIZER(blk_sem, 0);;
>
> struct blk_req {
> struct blkfront_aiocb aiocb;
> @@ -189,8 +192,10 @@
> time_t lasttime = 0;
>
> blk_dev = init_blkfront(NULL, &blk_info);
> - if (!blk_dev)
> + if (!blk_dev) {
> + up(&blk_sem);
> return;
> + }
>
> if (blk_info.info & VDISK_CDROM)
> printk("Block device is a CDROM\n");
> @@ -210,7 +215,7 @@
> blk_read_sector(blk_info.sectors-1);
> }
>
> - while (1) {
> + while (!do_shutdown) {
> uint64_t sector = rand() % blk_info.sectors;
> struct timeval tv;
> #ifdef BLKTEST_WRITE
> @@ -235,6 +240,7 @@
> }
> #endif
> }
> + up(&blk_sem);
> }
>
> #define WIDTH 800
> @@ -293,7 +299,6 @@
> xfree(mfns);
> if (!fb_dev) {
> xfree(fb);
> - return;
> }
> up(&fbfront_sem);
> }
> @@ -330,17 +335,21 @@
> }
>
> static struct kbdfront_dev *kbd_dev;
> +static struct semaphore kbd_sem = __SEMAPHORE_INITIALIZER(kbd_sem, 0);
> static void kbdfront_thread(void *p)
> {
> DEFINE_WAIT(w);
> DEFINE_WAIT(w2);
> + DEFINE_WAIT(w3);
> int x = WIDTH / 2, y = HEIGHT / 2, z = 0;
>
> kbd_dev = init_kbdfront(NULL, 1);
> - if (!kbd_dev)
> + down(&fbfront_sem);
> + if (!kbd_dev) {
> + up(&kbd_sem);
> return;
> + }
>
> - down(&fbfront_sem);
> refresh_cursor(x, y);
> while (1) {
> union xenkbd_in_event kbdevent;
> @@ -349,6 +358,11 @@
>
> add_waiter(w, kbdfront_queue);
> add_waiter(w2, fbfront_queue);
> + add_waiter(w3, shutdown_queue);
> +
> + rmb();
> + if (do_shutdown)
> + break;
>
> while (kbdfront_receive(kbd_dev, &kbdevent, 1) != 0) {
> sleep = 0;
> @@ -391,9 +405,11 @@
> fbfront_update(fb_dev, x - 16, y - 16, 33, 33);
> }
> } else if (kbdevent.key.keycode == KEY_Q) {
> - struct sched_shutdown sched_shutdown = { .reason =
> SHUTDOWN_poweroff };
> - HYPERVISOR_sched_op(SCHEDOP_shutdown, &sched_shutdown);
> - do_exit();
> + shutdown_reason = SHUTDOWN_poweroff;
> + wmb();
> + do_shutdown = 1;
> + wmb();
> + wake_up(&shutdown_queue);
> }
> break;
> }
> @@ -410,11 +426,16 @@
> }
> if (sleep)
> schedule();
> + remove_waiter(w3, shutdown_queue);
> + remove_waiter(w2, fbfront_queue);
> + remove_waiter(w, kbdfront_queue);
> }
> + up(&kbd_sem);
> }
>
> #ifdef CONFIG_PCIFRONT
> static struct pcifront_dev *pci_dev;
> +static struct semaphore pci_sem = __SEMAPHORE_INITIALIZER(pci_sem, 0);
>
> static void print_pcidev(unsigned int domain, unsigned int bus, unsigned int
> slot, unsigned int fun)
> {
> @@ -432,13 +453,60 @@
> {
> pcifront_watches(NULL);
> pci_dev = init_pcifront(NULL);
> - if (!pci_dev)
> + if (!pci_dev) {
> + up(&pci_sem);
> return;
> + }
> printk("PCI devices:\n");
> pcifront_scan(pci_dev, print_pcidev);
> + up(&pci_sem);
> }
> #endif
>
> +void shutdown_frontends(void)
> +{
> + down(&net_sem);
> + if (net_dev)
> + shutdown_netfront(net_dev);
> +
> + down(&blk_sem);
> + if (blk_dev)
> + shutdown_blkfront(blk_dev);
> +
> + if (fb_dev)
> + shutdown_fbfront(fb_dev);
> +
> + down(&kbd_sem);
> + if (kbd_dev)
> + shutdown_kbdfront(kbd_dev);
> +
> +#ifdef CONFIG_PCIFRONT
> + down(&pci_sem);
> + if (pci_dev)
> + shutdown_pcifront(pci_dev);
> +#endif
> +}
> +
> +static void shutdown_thread(void *p)
> +{
> + DEFINE_WAIT(w);
> +
> + while (1) {
> + add_waiter(w, shutdown_queue);
> + rmb();
> + if (do_shutdown) {
> + rmb();
> + break;
> + }
> + schedule();
> + remove_waiter(w, shutdown_queue);
> + }
> +
> + shutdown_frontends();
> +
> + HYPERVISOR_shutdown(shutdown_reason);
> +}
> +
> int app_main(start_info_t *si)
> {
> printk("Test main: start_info=%p\n", si);
> @@ -451,25 +519,6 @@
> #ifdef CONFIG_PCIFRONT
> create_thread("pcifront", pcifront_thread, si);
> #endif
> + create_thread("shutdown", shutdown_thread, si);
> return 0;
> }
> -
> -void shutdown_frontends(void)
> -{
> - if (net_dev)
> - shutdown_netfront(net_dev);
> -
> - if (blk_dev)
> - shutdown_blkfront(blk_dev);
> -
> - if (fb_dev)
> - shutdown_fbfront(fb_dev);
> -
> - if (kbd_dev)
> - shutdown_kbdfront(kbd_dev);
> -
> -#ifdef CONFIG_PCIFRONT
> - if (pci_dev)
> - shutdown_pcifront(pci_dev);
> -#endif
> -}
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxx
> http://lists.xen.org/xen-devel
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