diff options
Diffstat (limited to 'arch/um')
| -rw-r--r-- | arch/um/drivers/virtio_uml.c | 68 | ||||
| -rw-r--r-- | arch/um/include/linux/time-internal.h | 27 | ||||
| -rw-r--r-- | arch/um/include/shared/os.h | 1 | ||||
| -rw-r--r-- | arch/um/kernel/skas/syscall.c | 3 | ||||
| -rw-r--r-- | arch/um/kernel/time.c | 323 | ||||
| -rw-r--r-- | arch/um/os-Linux/file.c | 30 |
6 files changed, 435 insertions, 17 deletions
diff --git a/arch/um/drivers/virtio_uml.c b/arch/um/drivers/virtio_uml.c index 9b4c5b7c0f0d..be54d368e73d 100644 --- a/arch/um/drivers/virtio_uml.c +++ b/arch/um/drivers/virtio_uml.c @@ -26,6 +26,7 @@ #include <linux/virtio.h> #include <linux/virtio_config.h> #include <linux/virtio_ring.h> +#include <linux/time-internal.h> #include <shared/as-layout.h> #include <irq_kern.h> #include <init.h> @@ -64,6 +65,11 @@ struct virtio_uml_device { struct virtio_uml_vq_info { int kick_fd, call_fd; char name[32]; +#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT + struct virtqueue *vq; + vq_callback_t *callback; + struct time_travel_event defer; +#endif }; extern unsigned long long physmem_size, highmem; @@ -118,10 +124,27 @@ static int vhost_user_recv_header(int fd, struct vhost_user_msg *msg) static int vhost_user_recv(struct virtio_uml_device *vu_dev, int fd, struct vhost_user_msg *msg, - size_t max_payload_size) + size_t max_payload_size, bool wait) { size_t size; - int rc = vhost_user_recv_header(fd, msg); + int rc; + + /* + * In virtio time-travel mode, we're handling all the vhost-user + * FDs by polling them whenever appropriate. However, we may get + * into a situation where we're sending out an interrupt message + * to a device (e.g. a net device) and need to handle a simulation + * time message while doing so, e.g. one that tells us to update + * our idea of how long we can run without scheduling. + * + * Thus, we need to not just read() from the given fd, but need + * to also handle messages for the simulation time - this function + * does that for us while waiting for the given fd to be readable. + */ + if (wait) + time_travel_wait_readable(fd); + + rc = vhost_user_recv_header(fd, msg); if (rc == -ECONNRESET && vu_dev->registered) { struct virtio_uml_platform_data *pdata; @@ -143,7 +166,8 @@ static int vhost_user_recv_resp(struct virtio_uml_device *vu_dev, struct vhost_user_msg *msg, size_t max_payload_size) { - int rc = vhost_user_recv(vu_dev, vu_dev->sock, msg, max_payload_size); + int rc = vhost_user_recv(vu_dev, vu_dev->sock, msg, + max_payload_size, true); if (rc) return rc; @@ -173,7 +197,8 @@ static int vhost_user_recv_req(struct virtio_uml_device *vu_dev, struct vhost_user_msg *msg, size_t max_payload_size) { - int rc = vhost_user_recv(vu_dev, vu_dev->req_fd, msg, max_payload_size); + int rc = vhost_user_recv(vu_dev, vu_dev->req_fd, msg, + max_payload_size, false); if (rc) return rc; @@ -700,6 +725,8 @@ static bool vu_notify(struct virtqueue *vq) const uint64_t n = 1; int rc; + time_travel_propagate_time(); + if (info->kick_fd < 0) { struct virtio_uml_device *vu_dev; @@ -847,6 +874,23 @@ out: return rc; } +#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT +static void vu_defer_irq_handle(struct time_travel_event *d) +{ + struct virtio_uml_vq_info *info; + + info = container_of(d, struct virtio_uml_vq_info, defer); + info->callback(info->vq); +} + +static void vu_defer_irq_callback(struct virtqueue *vq) +{ + struct virtio_uml_vq_info *info = vq->priv; + + time_travel_add_irq_event(&info->defer); +} +#endif + static struct virtqueue *vu_setup_vq(struct virtio_device *vdev, unsigned index, vq_callback_t *callback, const char *name, bool ctx) @@ -866,6 +910,19 @@ static struct virtqueue *vu_setup_vq(struct virtio_device *vdev, snprintf(info->name, sizeof(info->name), "%s.%d-%s", pdev->name, pdev->id, name); +#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT + /* + * When we get an interrupt, we must bounce it through the simulation + * calendar (the simtime device), except for the simtime device itself + * since that's part of the simulation control. + */ + if (time_travel_mode == TT_MODE_EXTERNAL && callback) { + info->callback = callback; + callback = vu_defer_irq_callback; + time_travel_set_event_fn(&info->defer, vu_defer_irq_handle); + } +#endif + vq = vring_create_virtqueue(index, num, PAGE_SIZE, vdev, true, true, ctx, vu_notify, callback, info->name); if (!vq) { @@ -874,6 +931,9 @@ static struct virtqueue *vu_setup_vq(struct virtio_device *vdev, } vq->priv = info; num = virtqueue_get_vring_size(vq); +#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT + info->vq = vq; +#endif if (vu_dev->protocol_features & BIT_ULL(VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS)) { diff --git a/arch/um/include/linux/time-internal.h b/arch/um/include/linux/time-internal.h index eb1f84616edb..e21655926f08 100644 --- a/arch/um/include/linux/time-internal.h +++ b/arch/um/include/linux/time-internal.h @@ -15,6 +15,7 @@ enum time_travel_mode { TT_MODE_OFF, TT_MODE_BASIC, TT_MODE_INFCPU, + TT_MODE_EXTERNAL, }; #ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT @@ -35,6 +36,24 @@ time_travel_set_event_fn(struct time_travel_event *e, { e->fn = fn; } + +void __time_travel_propagate_time(void); + +static inline void time_travel_propagate_time(void) +{ + if (time_travel_mode == TT_MODE_EXTERNAL) + __time_travel_propagate_time(); +} + +void __time_travel_wait_readable(int fd); + +static inline void time_travel_wait_readable(int fd) +{ + if (time_travel_mode == TT_MODE_EXTERNAL) + __time_travel_wait_readable(fd); +} + +void time_travel_add_irq_event(struct time_travel_event *e); #else struct time_travel_event { }; @@ -47,5 +66,13 @@ static inline void time_travel_sleep(unsigned long long duration) /* this is a macro so the event/function need not exist */ #define time_travel_set_event_fn(e, fn) do {} while (0) + +static inline void time_travel_propagate_time(void) +{ +} + +static inline void time_travel_wait_readable(int fd) +{ +} #endif /* CONFIG_UML_TIME_TRAVEL_SUPPORT */ #endif /* __TIMER_INTERNAL_H__ */ diff --git a/arch/um/include/shared/os.h b/arch/um/include/shared/os.h index 0f30204b6afa..f467d28fc0b4 100644 --- a/arch/um/include/shared/os.h +++ b/arch/um/include/shared/os.h @@ -181,6 +181,7 @@ extern int os_falloc_punch(int fd, unsigned long long offset, int count); extern int os_eventfd(unsigned int initval, int flags); extern int os_sendmsg_fds(int fd, const void *buf, unsigned int len, const int *fds, unsigned int fds_num); +int os_poll(unsigned int n, const int *fds); /* start_up.c */ extern void os_early_checks(void); diff --git a/arch/um/kernel/skas/syscall.c b/arch/um/kernel/skas/syscall.c index 2e82820f7d29..0a12d5a09217 100644 --- a/arch/um/kernel/skas/syscall.c +++ b/arch/um/kernel/skas/syscall.c @@ -24,7 +24,8 @@ void handle_syscall(struct uml_pt_regs *r) * went to sleep, even if said userspace interacts with the kernel in * various ways. */ - if (time_travel_mode == TT_MODE_INFCPU) + if (time_travel_mode == TT_MODE_INFCPU || + time_travel_mode == TT_MODE_EXTERNAL) schedule(); /* Initialize the syscall number and default return value. */ diff --git a/arch/um/kernel/time.c b/arch/um/kernel/time.c index cdebe96308d7..15c4825b857e 100644 --- a/arch/um/kernel/time.c +++ b/arch/um/kernel/time.c @@ -20,10 +20,12 @@ #include <kern_util.h> #include <os.h> #include <linux/time-internal.h> +#include <linux/um_timetravel.h> #include <shared/init.h> #ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT enum time_travel_mode time_travel_mode; +EXPORT_SYMBOL_GPL(time_travel_mode); static bool time_travel_start_set; static unsigned long long time_travel_start; @@ -32,6 +34,12 @@ static LIST_HEAD(time_travel_events); static unsigned long long time_travel_timer_interval; static unsigned long long time_travel_next_event; static struct time_travel_event time_travel_timer_event; +static int time_travel_ext_fd = -1; +static unsigned int time_travel_ext_waiting; +static bool time_travel_ext_prev_request_valid; +static unsigned long long time_travel_ext_prev_request; +static bool time_travel_ext_free_until_valid; +static unsigned long long time_travel_ext_free_until; static void time_travel_set_time(unsigned long long ns) { @@ -41,6 +49,199 @@ static void time_travel_set_time(unsigned long long ns) time_travel_time = ns; } +enum time_travel_message_handling { + TTMH_IDLE, + TTMH_POLL, + TTMH_READ, +}; + +static void time_travel_handle_message(struct um_timetravel_msg *msg, + enum time_travel_message_handling mode) +{ + struct um_timetravel_msg resp = { + .op = UM_TIMETRAVEL_ACK, + }; + int ret; + + /* + * Poll outside the locked section (if we're not called to only read + * the response) so we can get interrupts for e.g. virtio while we're + * here, but then we need to lock to not get interrupted between the + * read of the message and write of the ACK. + */ + if (mode != TTMH_READ) { + while (os_poll(1, &time_travel_ext_fd) != 0) { + if (mode == TTMH_IDLE) { + BUG_ON(!irqs_disabled()); + local_irq_enable(); + local_irq_disable(); + } + } + } + + ret = os_read_file(time_travel_ext_fd, msg, sizeof(*msg)); + + if (ret == 0) + panic("time-travel external link is broken\n"); + if (ret != sizeof(*msg)) + panic("invalid time-travel message - %d bytes\n", ret); + + switch (msg->op) { + default: + WARN_ONCE(1, "time-travel: unexpected message %lld\n", + (unsigned long long)msg->op); + break; + case UM_TIMETRAVEL_ACK: + return; + case UM_TIMETRAVEL_RUN: + time_travel_set_time(msg->time); + break; + case UM_TIMETRAVEL_FREE_UNTIL: + time_travel_ext_free_until_valid = true; + time_travel_ext_free_until = msg->time; + break; + } + + os_write_file(time_travel_ext_fd, &resp, sizeof(resp)); +} + +static u64 time_travel_ext_req(u32 op, u64 time) +{ + static int seq; + int mseq = ++seq; + struct um_timetravel_msg msg = { + .op = op, + .time = time, + .seq = mseq, + }; + unsigned long flags; + + /* + * We need to save interrupts here and only restore when we + * got the ACK - otherwise we can get interrupted and send + * another request while we're still waiting for an ACK, but + * the peer doesn't know we got interrupted and will send + * the ACKs in the same order as the message, but we'd need + * to see them in the opposite order ... + * + * This wouldn't matter *too* much, but some ACKs carry the + * current time (for UM_TIMETRAVEL_GET) and getting another + * ACK without a time would confuse us a lot! + * + * The sequence number assignment that happens here lets us + * debug such message handling issues more easily. + */ + local_irq_save(flags); + os_write_file(time_travel_ext_fd, &msg, sizeof(msg)); + + while (msg.op != UM_TIMETRAVEL_ACK) + time_travel_handle_message(&msg, TTMH_READ); + + if (msg.seq != mseq) + panic("time-travel: ACK message has different seqno! op=%d, seq=%d != %d time=%lld\n", + msg.op, msg.seq, mseq, msg.time); + + if (op == UM_TIMETRAVEL_GET) + time_travel_set_time(msg.time); + local_irq_restore(flags); + + return msg.time; +} + +void __time_travel_wait_readable(int fd) +{ + int fds[2] = { fd, time_travel_ext_fd }; + int ret; + + if (time_travel_mode != TT_MODE_EXTERNAL) + return; + + while ((ret = os_poll(2, fds))) { + struct um_timetravel_msg msg; + + if (ret == 1) + time_travel_handle_message(&msg, TTMH_READ); + } +} +EXPORT_SYMBOL_GPL(__time_travel_wait_readable); + +static void time_travel_ext_update_request(unsigned long long time) +{ + if (time_travel_mode != TT_MODE_EXTERNAL) + return; + + /* asked for exactly this time previously */ + if (time_travel_ext_prev_request_valid && + time == time_travel_ext_prev_request) + return; + + time_travel_ext_prev_request = time; + time_travel_ext_prev_request_valid = true; + time_travel_ext_req(UM_TIMETRAVEL_REQUEST, time); +} + +void __time_travel_propagate_time(void) +{ + time_travel_ext_req(UM_TIMETRAVEL_UPDATE, time_travel_time); +} +EXPORT_SYMBOL_GPL(__time_travel_propagate_time); + +/* returns true if we must do a wait to the simtime device */ +static bool time_travel_ext_request(unsigned long long time) +{ + /* + * If we received an external sync point ("free until") then we + * don't have to request/wait for anything until then, unless + * we're already waiting. + */ + if (!time_travel_ext_waiting && time_travel_ext_free_until_valid && + time < time_travel_ext_free_until) + return false; + + time_travel_ext_update_request(time); + return true; +} + +static void time_travel_ext_wait(bool idle) +{ + struct um_timetravel_msg msg = { + .op = UM_TIMETRAVEL_ACK, + }; + + time_travel_ext_prev_request_valid = false; + time_travel_ext_waiting++; + + time_travel_ext_req(UM_TIMETRAVEL_WAIT, -1); + + /* + * Here we are deep in the idle loop, so we have to break out of the + * kernel abstraction in a sense and implement this in terms of the + * UML system waiting on the VQ interrupt while sleeping, when we get + * the signal it'll call time_travel_ext_vq_notify_done() completing the + * call. + */ + while (msg.op != UM_TIMETRAVEL_RUN) + time_travel_handle_message(&msg, idle ? TTMH_IDLE : TTMH_POLL); + + time_travel_ext_waiting--; + + /* we might request more stuff while polling - reset when we run */ + time_travel_ext_prev_request_valid = false; +} + +static void time_travel_ext_get_time(void) +{ + time_travel_ext_req(UM_TIMETRAVEL_GET, -1); +} + +static void __time_travel_update_time(unsigned long long ns, bool idle) +{ + if (time_travel_mode == TT_MODE_EXTERNAL && time_travel_ext_request(ns)) + time_travel_ext_wait(idle); + else + time_travel_set_time(ns); +} + static struct time_travel_event *time_travel_first_event(void) { return list_first_entry_or_null(&time_travel_events, @@ -85,6 +286,7 @@ static void __time_travel_add_event(struct time_travel_event *e, list_add_tail(&e->list, &time_travel_events); tmp = time_travel_first_event(); + time_travel_ext_update_request(tmp->time); time_travel_next_event = tmp->time; } @@ -106,8 +308,21 @@ void time_travel_periodic_timer(struct time_travel_event *e) static void time_travel_deliver_event(struct time_travel_event *e) { - /* this is basically just deliver_alarm(), handles IRQs itself */ - e->fn(e); + if (e == &time_travel_timer_event) { + /* + * deliver_alarm() does the irq_enter/irq_exit + * by itself, so must handle it specially here + */ + e->fn(e); + } else { + unsigned long flags; + + local_irq_save(flags); + irq_enter(); + e->fn(e); + irq_exit(); + local_irq_restore(flags); + } } static bool time_travel_del_event(struct time_travel_event *e) @@ -119,13 +334,13 @@ static bool time_travel_del_event(struct time_travel_event *e) return true; } -static void time_travel_update_time(unsigned long long next, bool retearly) +static void time_travel_update_time(unsigned long long next, bool idle) { struct time_travel_event ne = { .onstack = true, }; struct time_travel_event *e; - bool finished = retearly; + bool finished = idle; /* add it without a handler - we deal with that specifically below */ __time_travel_add_event(&ne, next); @@ -134,7 +349,7 @@ static void time_travel_update_time(unsigned long long next, bool retearly) e = time_travel_first_event(); BUG_ON(!e); - time_travel_set_time(e->time); + __time_travel_update_time(e->time, idle); /* new events may have been inserted while we were waiting */ if (e == time_travel_first_event()) { @@ -150,11 +365,29 @@ static void time_travel_update_time(unsigned long long next, bool retearly) time_travel_deliver_event(e); } } - } while (!finished); + + e = time_travel_first_event(); + if (e) + time_travel_ext_update_request(e->time); + } while (ne.pending && !finished); time_travel_del_event(&ne); } +void time_travel_add_irq_event(struct time_travel_event *e) +{ + BUG_ON(time_travel_mode != TT_MODE_EXTERNAL); + + time_travel_ext_get_time(); + /* + * We could model interrupt latency here, for now just + * don't have any latency at all and request the exact + * same time (again) to run the interrupt... + */ + time_travel_add_event(e, time_travel_time); +} +EXPORT_SYMBOL_GPL(time_travel_add_irq_event); + static void time_travel_oneshot_timer(struct time_travel_event *e) { deliver_alarm(); @@ -199,6 +432,42 @@ static void time_travel_set_interval(unsigned long long interval) { time_travel_timer_interval = interval; } + +static int time_travel_connect_external(const char *socket) +{ + const char *sep; + unsigned long long id = (unsigned long long)-1; + int rc; + + if ((sep = strchr(socket, ':'))) { + char buf[25] = {}; + if (sep - socket > sizeof(buf) - 1) + goto invalid_number; + + memcpy(buf, socket, sep - socket); + if (kstrtoull(buf, 0, &id)) { +invalid_number: + panic("time-travel: invalid external ID in string '%s'\n", + socket); + return -EINVAL; + } + + socket = sep + 1; + } + + rc = os_connect_socket(socket); + if (rc < 0) { + panic("time-travel: failed to connect to external socket %s\n", + socket); + return rc; + } + + time_travel_ext_fd = rc; + + time_travel_ext_req(UM_TIMETRAVEL_START, id); + + return 1; +} #else /* CONFIG_UML_TIME_TRAVEL_SUPPORT */ #define time_travel_start_set 0 #define time_travel_start 0 @@ -216,6 +485,9 @@ static void time_travel_set_interval(unsigned long long interval) { } +/* fail link if this actually gets used */ +extern u64 time_travel_ext_req(u32 op, u64 time); + /* these are empty macros so the struct/fn need not exist */ #define time_travel_add_event(e, time) do { } while (0) #define time_travel_del_event(e) do { } while (0) @@ -246,7 +518,8 @@ static int itimer_shutdown(struct clock_event_device *evt) if (time_travel_mode != TT_MODE_OFF) time_travel_del_event(&time_travel_timer_event); - if (time_travel_mode != TT_MODE_INFCPU) + if (time_travel_mode != TT_MODE_INFCPU && + time_travel_mode != TT_MODE_EXTERNAL) os_timer_disable(); return 0; @@ -265,7 +538,8 @@ static int itimer_set_periodic(struct clock_event_device *evt) time_travel_time + interval); } - if (time_travel_mode != TT_MODE_INFCPU) + if (time_travel_mode != TT_MODE_INFCPU && + time_travel_mode != TT_MODE_EXTERNAL) os_timer_set_interval(interval); return 0; @@ -284,7 +558,8 @@ static int itimer_next_event(unsigned long delta, time_travel_time + delta); } - if (time_travel_mode != TT_MODE_INFCPU) + if (time_travel_mode != TT_MODE_INFCPU && + time_travel_mode != TT_MODE_EXTERNAL) return os_timer_one_shot(delta); return 0; @@ -335,8 +610,14 @@ static u64 timer_read(struct clocksource *cs) * stuck in loops that expect time to move more than the * exact requested sleep amount, e.g. python's socket server, * see https://bugs.python.org/issue37026. + * + * However, don't do that when we're in interrupt or such as + * then we might recurse into our own processing, and get to + * even more waiting, and that's not good - it messes up the + * "what do I do next" and onstack event we use to know when + * to return from time_travel_update_time(). */ - if (!irqs_disabled()) + if (!irqs_disabled() && !in_interrupt() && !in_softirq()) time_travel_update_time(time_travel_time + TIMER_MULTIPLIER, false); @@ -383,6 +664,8 @@ void read_persistent_clock64(struct timespec64 *ts) if (time_travel_start_set) nsecs = time_travel_start + time_travel_time; + else if (time_travel_mode == TT_MODE_EXTERNAL) + nsecs = time_travel_ext_req(UM_TIMETRAVEL_GET_TOD, -1); else nsecs = os_persistent_clock_emulation(); @@ -399,7 +682,8 @@ void __init time_init(void) #ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT unsigned long calibrate_delay_is_known(void) { - if (time_travel_mode == TT_MODE_INFCPU) + if (time_travel_mode == TT_MODE_INFCPU || + time_travel_mode == TT_MODE_EXTERNAL) return 1; return 0; } @@ -413,6 +697,13 @@ int setup_time_travel(char *str) return 1; } + if (strncmp(str, "=ext:", 5) == 0) { + time_travel_mode = TT_MODE_EXTERNAL; + timer_clockevent.name = "time-travel-timer-external"; + timer_clocksource.name = "time-travel-clock-external"; + return time_travel_connect_external(str + 5); + } + if (!*str) { time_travel_mode = TT_MODE_BASIC; timer_clockevent.name = "time-travel-timer"; @@ -437,7 +728,15 @@ __uml_help(setup_time_travel, "are no wall clock timers, and any CPU processing happens - as seen from the\n" "guest - instantly. This can be useful for accurate simulation regardless of\n" "debug overhead, physical CPU speed, etc. but is somewhat dangerous as it can\n" -"easily lead to getting stuck (e.g. if anything in the system busy loops).\n"); +"easily lead to getting stuck (e.g. if anything in the system busy loops).\n" +"\n" +"time-travel=ext:[ID:]/path/to/socket\n" +"This enables time travel mode similar to =inf-cpu, except the system will\n" +"use the given socket to coordinate with a central scheduler, in order to\n" +"have more than one system simultaneously be on simulated time. The virtio\n" +"driver code in UML knows about this so you can also simulate networks and\n" +"devices using it, assuming the device has the right capabilities.\n" +"The optional ID is a 64-bit integer that's sent to the central scheduler.\n"); int setup_time_travel_start(char *str) { diff --git a/arch/um/os-Linux/file.c b/arch/um/os-Linux/file.c index 5c819f89b8c2..26ecbd64c409 100644 --- a/arch/um/os-Linux/file.c +++ b/arch/um/os-Linux/file.c @@ -5,6 +5,7 @@ #include <stdio.h> #include <unistd.h> +#include <stdlib.h> #include <errno.h> #include <fcntl.h> #include <signal.h> @@ -17,6 +18,7 @@ #include <sys/un.h> #include <sys/types.h> #include <sys/eventfd.h> +#include <poll.h> #include <os.h> static void copy_stat(struct uml_stat *dst, const struct stat64 *src) @@ -665,3 +667,31 @@ int os_sendmsg_fds(int fd, const void *buf, unsigned int len, const int *fds, return -errno; return err; } + +int os_poll(unsigned int n, const int *fds) +{ + /* currently need 2 FDs at most so avoid dynamic allocation */ + struct pollfd pollfds[2] = {}; + unsigned int i; + int ret; + + if (n > ARRAY_SIZE(pollfds)) + return -EINVAL; + + for (i = 0; i < n; i++) { + pollfds[i].fd = fds[i]; + pollfds[i].events = POLLIN; + } + + ret = poll(pollfds, n, -1); + if (ret < 0) + return -errno; + + /* Return the index of the available FD */ + for (i = 0; i < n; i++) { + if (pollfds[i].revents) + return i; + } + + return -EIO; +} |