#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
+#include <sys/eventfd.h>
#include <fcntl.h>
#include <stdbool.h>
#include <errno.h>
/*:*/
#define PAGE_PRESENT 0x7 /* Present, RW, Execute */
-#define NET_PEERNUM 1
#define BRIDGE_PFX "bridge:"
#ifndef SIOCBRADDIF
#define SIOCBRADDIF 0x89a2 /* add interface to bridge */
do { if (verbose) printf(args); } while(0)
/*:*/
-/* File descriptors for the Waker. */
-struct {
- int pipe[2];
-} waker_fds;
-
/* The pointer to the start of guest memory. */
static void *guest_base;
/* The maximum guest physical address allowed, and maximum possible. */
static unsigned long guest_limit, guest_max;
-/* The pipe for signal hander to write to. */
-static int timeoutpipe[2];
-static unsigned int timeout_usec = 500;
/* The /dev/lguest file descriptor. */
static int lguest_fd;
/* This is our list of devices. */
struct device_list
{
- /* Summary information about the devices in our list: ready to pass to
- * select() to ask which need servicing.*/
- fd_set infds;
- int max_infd;
-
/* Counter to assign interrupt numbers. */
unsigned int next_irq;
/* The name of this device, for --verbose. */
const char *name;
- /* If handle_input is set, it wants to be called when this file
- * descriptor is ready. */
- int fd;
- bool (*handle_input)(struct device *me);
-
/* Any queues attached to this device */
struct virtqueue *vq;
- /* Handle status being finalized (ie. feature bits stable). */
- void (*ready)(struct device *me);
+ /* Is it operational */
+ bool running;
/* Device-specific data. */
void *priv;
/* Last available index we saw. */
u16 last_avail_idx;
- /* The routine to call when the Guest pings us, or timeout. */
- void (*handle_output)(struct virtqueue *me, bool timeout);
+ /* Eventfd where Guest notifications arrive. */
+ int eventfd;
- /* Is this blocked awaiting a timer? */
- bool blocked;
+ /* Function for the thread which is servicing this virtqueue. */
+ void (*service)(struct virtqueue *vq);
+ pid_t thread;
};
/* Remember the arguments to the program so we can "reboot" */
static char **main_args;
+/* The original tty settings to restore on exit. */
+static struct termios orig_term;
+
/* We have to be careful with barriers: our devices are all run in separate
* threads and so we need to make sure that changes visible to the Guest happen
* in precise order. */
}
/*:*/
-static void add_device_fd(int fd)
-{
- FD_SET(fd, &devices.infds);
- if (fd > devices.max_infd)
- devices.max_infd = fd;
-}
-
-/*L:200
- * The Waker.
- *
- * With console, block and network devices, we can have lots of input which we
- * need to process. We could try to tell the kernel what file descriptors to
- * watch, but handing a file descriptor mask through to the kernel is fairly
- * icky.
- *
- * Instead, we clone off a thread which watches the file descriptors and writes
- * the LHREQ_BREAK command to the /dev/lguest file descriptor to tell the Host
- * stop running the Guest. This causes the Launcher to return from the
- * /dev/lguest read with -EAGAIN, where it will write to /dev/lguest to reset
- * the LHREQ_BREAK and wake us up again.
- *
- * This, of course, is merely a different *kind* of icky.
- *
- * Given my well-known antipathy to threads, I'd prefer to use processes. But
- * it's easier to share Guest memory with threads, and trivial to share the
- * devices.infds as the Launcher changes it.
- */
-static int waker(void *unused)
-{
- /* Close the write end of the pipe: only the Launcher has it open. */
- close(waker_fds.pipe[1]);
-
- for (;;) {
- fd_set rfds = devices.infds;
- unsigned long args[] = { LHREQ_BREAK, 1 };
- unsigned int maxfd = devices.max_infd;
-
- /* We also listen to the pipe from the Launcher. */
- FD_SET(waker_fds.pipe[0], &rfds);
- if (waker_fds.pipe[0] > maxfd)
- maxfd = waker_fds.pipe[0];
-
- /* Wait until input is ready from one of the devices. */
- select(maxfd+1, &rfds, NULL, NULL, NULL);
-
- /* Message from Launcher? */
- if (FD_ISSET(waker_fds.pipe[0], &rfds)) {
- char c;
- /* If this fails, then assume Launcher has exited.
- * Don't do anything on exit: we're just a thread! */
- if (read(waker_fds.pipe[0], &c, 1) != 1)
- _exit(0);
- continue;
- }
-
- /* Send LHREQ_BREAK command to snap the Launcher out of it. */
- pwrite(lguest_fd, args, sizeof(args), cpu_id);
- }
- return 0;
-}
-
-/* This routine just sets up a pipe to the Waker process. */
-static void setup_waker(void)
-{
- /* This pipe is closed when Launcher dies, telling Waker. */
- if (pipe(waker_fds.pipe) != 0)
- err(1, "Creating pipe for Waker");
-
- if (clone(waker, malloc(4096) + 4096, CLONE_VM | SIGCHLD, NULL) == -1)
- err(1, "Creating Waker");
-}
-
/*
* Device Handling.
*
* number of output then some number of input descriptors, it's actually two
* iovecs, but we pack them into one and note how many of each there were.
*
- * This function returns the descriptor number found, or vq->vring.num (which
- * is never a valid descriptor number) if none was found. */
-static unsigned get_vq_desc(struct virtqueue *vq,
- struct iovec iov[],
- unsigned int *out_num, unsigned int *in_num)
+ * This function returns the descriptor number found. */
+static unsigned wait_for_vq_desc(struct virtqueue *vq,
+ struct iovec iov[],
+ unsigned int *out_num, unsigned int *in_num)
{
unsigned int i, head;
- u16 last_avail;
+ u16 last_avail = lg_last_avail(vq);
+
+ while (last_avail == vq->vring.avail->idx) {
+ u64 event;
+
+ /* Nothing new? Wait for eventfd to tell us they refilled. */
+ if (read(vq->eventfd, &event, sizeof(event)) != sizeof(event))
+ errx(1, "Event read failed?");
+ }
/* Check it isn't doing very strange things with descriptor numbers. */
- last_avail = lg_last_avail(vq);
if ((u16)(vq->vring.avail->idx - last_avail) > vq->vring.num)
errx(1, "Guest moved used index from %u to %u",
last_avail, vq->vring.avail->idx);
- /* If there's nothing new since last we looked, return invalid. */
- if (vq->vring.avail->idx == last_avail)
- return vq->vring.num;
-
/* Grab the next descriptor number they're advertising, and increment
* the index we've seen. */
head = vq->vring.avail->ring[last_avail % vq->vring.num];
/*
* The Console
*
- * Here is the input terminal setting we save, and the routine to restore them
- * on exit so the user gets their terminal back. */
-static struct termios orig_term;
-static void restore_term(void)
-{
- tcsetattr(STDIN_FILENO, TCSANOW, &orig_term);
-}
-
-/* We associate some data with the console for our exit hack. */
+ * We associate some data with the console for our exit hack. */
struct console_abort
{
/* How many times have they hit ^C? */
};
/* This is the routine which handles console input (ie. stdin). */
-static bool handle_console_input(struct device *dev)
+static void console_input(struct virtqueue *vq)
{
int len;
unsigned int head, in_num, out_num;
- struct iovec iov[dev->vq->vring.num];
- struct console_abort *abort = dev->priv;
-
- /* First we need a console buffer from the Guests's input virtqueue. */
- head = get_vq_desc(dev->vq, iov, &out_num, &in_num);
-
- /* If they're not ready for input, stop listening to this file
- * descriptor. We'll start again once they add an input buffer. */
- if (head == dev->vq->vring.num)
- return false;
+ struct console_abort *abort = vq->dev->priv;
+ struct iovec iov[vq->vring.num];
+ /* Make sure there's a descriptor waiting. */
+ head = wait_for_vq_desc(vq, iov, &out_num, &in_num);
if (out_num)
errx(1, "Output buffers in console in queue?");
- /* This is why we convert to iovecs: the readv() call uses them, and so
- * it reads straight into the Guest's buffer. */
- len = readv(dev->fd, iov, in_num);
+ /* Read it in. */
+ len = readv(STDIN_FILENO, iov, in_num);
if (len <= 0) {
- /* This implies that the console is closed, is /dev/null, or
- * something went terribly wrong. */
+ /* Ran out of input? */
warnx("Failed to get console input, ignoring console.");
- /* Put the input terminal back. */
- restore_term();
- /* Remove callback from input vq, so it doesn't restart us. */
- dev->vq->handle_output = NULL;
- /* Stop listening to this fd: don't call us again. */
- return false;
+ /* For simplicity, dying threads kill the whole Launcher. So
+ * just nap here. */
+ for (;;)
+ pause();
}
- /* Tell the Guest about the new input. */
- add_used_and_trigger(dev->vq, head, len);
+ add_used_and_trigger(vq, head, len);
/* Three ^C within one second? Exit.
*
- * This is such a hack, but works surprisingly well. Each ^C has to be
- * in a buffer by itself, so they can't be too fast. But we check that
- * we get three within about a second, so they can't be too slow. */
- if (len == 1 && ((char *)iov[0].iov_base)[0] == 3) {
- if (!abort->count++)
- gettimeofday(&abort->start, NULL);
- else if (abort->count == 3) {
- struct timeval now;
- gettimeofday(&now, NULL);
- if (now.tv_sec <= abort->start.tv_sec+1) {
- unsigned long args[] = { LHREQ_BREAK, 0 };
- /* Close the fd so Waker will know it has to
- * exit. */
- close(waker_fds.pipe[1]);
- /* Just in case Waker is blocked in BREAK, send
- * unbreak now. */
- write(lguest_fd, args, sizeof(args));
- exit(2);
- }
- abort->count = 0;
- }
- } else
- /* Any other key resets the abort counter. */
+ * This is such a hack, but works surprisingly well. Each ^C has to
+ * be in a buffer by itself, so they can't be too fast. But we check
+ * that we get three within about a second, so they can't be too
+ * slow. */
+ if (len != 1 || ((char *)iov[0].iov_base)[0] != 3) {
abort->count = 0;
+ return;
+ }
- /* Everything went OK! */
- return true;
+ abort->count++;
+ if (abort->count == 1)
+ gettimeofday(&abort->start, NULL);
+ else if (abort->count == 3) {
+ struct timeval now;
+ gettimeofday(&now, NULL);
+ /* Kill all Launcher processes with SIGINT, like normal ^C */
+ if (now.tv_sec <= abort->start.tv_sec+1)
+ kill(0, SIGINT);
+ abort->count = 0;
+ }
}
-/* Handling output for console is simple: we just get all the output buffers
- * and write them to stdout. */
-static void handle_console_output(struct virtqueue *vq, bool timeout)
+/* This is the routine which handles console output (ie. stdout). */
+static void console_output(struct virtqueue *vq)
{
unsigned int head, out, in;
struct iovec iov[vq->vring.num];
- /* Keep getting output buffers from the Guest until we run out. */
- while ((head = get_vq_desc(vq, iov, &out, &in)) != vq->vring.num) {
- if (in)
- errx(1, "Input buffers in output queue?");
- while (!iov_empty(iov, out)) {
- int len = writev(STDOUT_FILENO, iov, out);
- if (len <= 0)
- err(1, "Write to stdout gave %i", len);
- iov_consume(iov, out, len);
- }
- add_used_and_trigger(vq, head, 0);
+ head = wait_for_vq_desc(vq, iov, &out, &in);
+ if (in)
+ errx(1, "Input buffers in console output queue?");
+ while (!iov_empty(iov, out)) {
+ int len = writev(STDOUT_FILENO, iov, out);
+ if (len <= 0)
+ err(1, "Write to stdout gave %i", len);
+ iov_consume(iov, out, len);
}
-}
-
-/* This is called when we no longer want to hear about Guest changes to a
- * virtqueue. This is more efficient in high-traffic cases, but it means we
- * have to set a timer to check if any more changes have occurred. */
-static void block_vq(struct virtqueue *vq)
-{
- struct itimerval itm;
-
- vq->vring.used->flags |= VRING_USED_F_NO_NOTIFY;
- vq->blocked = true;
-
- itm.it_interval.tv_sec = 0;
- itm.it_interval.tv_usec = 0;
- itm.it_value.tv_sec = 0;
- itm.it_value.tv_usec = timeout_usec;
-
- setitimer(ITIMER_REAL, &itm, NULL);
+ add_used_and_trigger(vq, head, 0);
}
/*
* The Network
*
* Handling output for network is also simple: we get all the output buffers
- * and write them (ignoring the first element) to this device's file descriptor
- * (/dev/net/tun).
+ * and write them to /dev/net/tun.
*/
-static void handle_net_output(struct virtqueue *vq, bool timeout)
+struct net_info {
+ int tunfd;
+};
+
+static void net_output(struct virtqueue *vq)
{
- unsigned int head, out, in, num = 0;
+ struct net_info *net_info = vq->dev->priv;
+ unsigned int head, out, in;
struct iovec iov[vq->vring.num];
- static int last_timeout_num;
-
- /* Keep getting output buffers from the Guest until we run out. */
- while ((head = get_vq_desc(vq, iov, &out, &in)) != vq->vring.num) {
- if (in)
- errx(1, "Input buffers in output queue?");
- if (writev(vq->dev->fd, iov, out) < 0)
- err(1, "Writing network packet to tun");
- add_used_and_trigger(vq, head, 0);
- num++;
- }
- /* Block further kicks and set up a timer if we saw anything. */
- if (!timeout && num)
- block_vq(vq);
-
- /* We never quite know how long should we wait before we check the
- * queue again for more packets. We start at 500 microseconds, and if
- * we get fewer packets than last time, we assume we made the timeout
- * too small and increase it by 10 microseconds. Otherwise, we drop it
- * by one microsecond every time. It seems to work well enough. */
- if (timeout) {
- if (num < last_timeout_num)
- timeout_usec += 10;
- else if (timeout_usec > 1)
- timeout_usec--;
- last_timeout_num = num;
- }
+ head = wait_for_vq_desc(vq, iov, &out, &in);
+ if (in)
+ errx(1, "Input buffers in net output queue?");
+ if (writev(net_info->tunfd, iov, out) < 0)
+ errx(1, "Write to tun failed?");
+ add_used_and_trigger(vq, head, 0);
}
-/* This is where we handle a packet coming in from the tun device to our
+/* This is where we handle packets coming in from the tun device to our
* Guest. */
-static bool handle_tun_input(struct device *dev)
+static void net_input(struct virtqueue *vq)
{
- unsigned int head, in_num, out_num;
int len;
- struct iovec iov[dev->vq->vring.num];
-
- /* First we need a network buffer from the Guests's recv virtqueue. */
- head = get_vq_desc(dev->vq, iov, &out_num, &in_num);
- if (head == dev->vq->vring.num) {
- /* Now, it's expected that if we try to send a packet too
- * early, the Guest won't be ready yet. Wait until the device
- * status says it's ready. */
- /* FIXME: Actually want DRIVER_ACTIVE here. */
-
- /* Now tell it we want to know if new things appear. */
- dev->vq->vring.used->flags &= ~VRING_USED_F_NO_NOTIFY;
- wmb();
-
- /* We'll turn this back on if input buffers are registered. */
- return false;
- } else if (out_num)
- errx(1, "Output buffers in network recv queue?");
-
- /* Read the packet from the device directly into the Guest's buffer. */
- len = readv(dev->fd, iov, in_num);
+ unsigned int head, out, in;
+ struct iovec iov[vq->vring.num];
+ struct net_info *net_info = vq->dev->priv;
+
+ head = wait_for_vq_desc(vq, iov, &out, &in);
+ if (out)
+ errx(1, "Output buffers in net input queue?");
+ len = readv(net_info->tunfd, iov, in);
if (len <= 0)
- err(1, "reading network");
+ err(1, "Failed to read from tun.");
+ add_used_and_trigger(vq, head, len);
+}
- /* Tell the Guest about the new packet. */
- add_used_and_trigger(dev->vq, head, len);
+/* This is the helper to create threads. */
+static int do_thread(void *_vq)
+{
+ struct virtqueue *vq = _vq;
- verbose("tun input packet len %i [%02x %02x] (%s)\n", len,
- ((u8 *)iov[1].iov_base)[0], ((u8 *)iov[1].iov_base)[1],
- head != dev->vq->vring.num ? "sent" : "discarded");
+ for (;;)
+ vq->service(vq);
+ return 0;
+}
- /* All good. */
- return true;
+/* When a child dies, we kill our entire process group with SIGTERM. This
+ * also has the side effect that the shell restores the console for us! */
+static void kill_launcher(int signal)
+{
+ kill(0, SIGTERM);
}
-/*L:215 This is the callback attached to the network and console input
- * virtqueues: it ensures we try again, in case we stopped console or net
- * delivery because Guest didn't have any buffers. */
-static void enable_fd(struct virtqueue *vq, bool timeout)
+static void reset_device(struct device *dev)
{
- add_device_fd(vq->dev->fd);
- /* Snap the Waker out of its select loop. */
- write(waker_fds.pipe[1], "", 1);
+ struct virtqueue *vq;
+
+ verbose("Resetting device %s\n", dev->name);
+
+ /* Clear any features they've acked. */
+ memset(get_feature_bits(dev) + dev->feature_len, 0, dev->feature_len);
+
+ /* We're going to be explicitly killing threads, so ignore them. */
+ signal(SIGCHLD, SIG_IGN);
+
+ /* Zero out the virtqueues, get rid of their threads */
+ for (vq = dev->vq; vq; vq = vq->next) {
+ if (vq->thread != (pid_t)-1) {
+ kill(vq->thread, SIGTERM);
+ waitpid(vq->thread, NULL, 0);
+ vq->thread = (pid_t)-1;
+ }
+ memset(vq->vring.desc, 0,
+ vring_size(vq->config.num, LGUEST_VRING_ALIGN));
+ lg_last_avail(vq) = 0;
+ }
+ dev->running = false;
+
+ /* Now we care if threads die. */
+ signal(SIGCHLD, (void *)kill_launcher);
}
-static void net_enable_fd(struct virtqueue *vq, bool timeout)
+static void create_thread(struct virtqueue *vq)
{
- /* We don't need to know again when Guest refills receive buffer. */
- vq->vring.used->flags |= VRING_USED_F_NO_NOTIFY;
- enable_fd(vq, timeout);
+ /* Create stack for thread and run it. Since stack grows
+ * upwards, we point the stack pointer to the end of this
+ * region. */
+ char *stack = malloc(32768);
+ unsigned long args[] = { LHREQ_EVENTFD,
+ vq->config.pfn*getpagesize(), 0 };
+
+ /* Create a zero-initialized eventfd. */
+ vq->eventfd = eventfd(0, 0);
+ if (vq->eventfd < 0)
+ err(1, "Creating eventfd");
+ args[2] = vq->eventfd;
+
+ /* Attach an eventfd to this virtqueue: it will go off
+ * when the Guest does an LHCALL_NOTIFY for this vq. */
+ if (write(lguest_fd, &args, sizeof(args)) != 0)
+ err(1, "Attaching eventfd");
+
+ /* CLONE_VM: because it has to access the Guest memory, and
+ * SIGCHLD so we get a signal if it dies. */
+ vq->thread = clone(do_thread, stack + 32768, CLONE_VM | SIGCHLD, vq);
+ if (vq->thread == (pid_t)-1)
+ err(1, "Creating clone");
+ /* We close our local copy, now the child has it. */
+ close(vq->eventfd);
}
-/* When the Guest tells us they updated the status field, we handle it. */
-static void update_device_status(struct device *dev)
+static void start_device(struct device *dev)
{
+ unsigned int i;
struct virtqueue *vq;
- /* This is a reset. */
- if (dev->desc->status == 0) {
- verbose("Resetting device %s\n", dev->name);
+ verbose("Device %s OK: offered", dev->name);
+ for (i = 0; i < dev->feature_len; i++)
+ verbose(" %02x", get_feature_bits(dev)[i]);
+ verbose(", accepted");
+ for (i = 0; i < dev->feature_len; i++)
+ verbose(" %02x", get_feature_bits(dev)
+ [dev->feature_len+i]);
+
+ for (vq = dev->vq; vq; vq = vq->next) {
+ if (vq->service)
+ create_thread(vq);
+ }
+ dev->running = true;
+}
+
+static void cleanup_devices(void)
+{
+ struct device *dev;
+
+ for (dev = devices.dev; dev; dev = dev->next)
+ reset_device(dev);
- /* Clear any features they've acked. */
- memset(get_feature_bits(dev) + dev->feature_len, 0,
- dev->feature_len);
+ /* If we saved off the original terminal settings, restore them now. */
+ if (orig_term.c_lflag & (ISIG|ICANON|ECHO))
+ tcsetattr(STDIN_FILENO, TCSANOW, &orig_term);
+}
- /* Zero out the virtqueues. */
- for (vq = dev->vq; vq; vq = vq->next) {
- memset(vq->vring.desc, 0,
- vring_size(vq->config.num, LGUEST_VRING_ALIGN));
- lg_last_avail(vq) = 0;
- }
- } else if (dev->desc->status & VIRTIO_CONFIG_S_FAILED) {
+/* When the Guest tells us they updated the status field, we handle it. */
+static void update_device_status(struct device *dev)
+{
+ /* A zero status is a reset, otherwise it's a set of flags. */
+ if (dev->desc->status == 0)
+ reset_device(dev);
+ else if (dev->desc->status & VIRTIO_CONFIG_S_FAILED) {
warnx("Device %s configuration FAILED", dev->name);
+ if (dev->running)
+ reset_device(dev);
} else if (dev->desc->status & VIRTIO_CONFIG_S_DRIVER_OK) {
- unsigned int i;
-
- verbose("Device %s OK: offered", dev->name);
- for (i = 0; i < dev->feature_len; i++)
- verbose(" %02x", get_feature_bits(dev)[i]);
- verbose(", accepted");
- for (i = 0; i < dev->feature_len; i++)
- verbose(" %02x", get_feature_bits(dev)
- [dev->feature_len+i]);
-
- if (dev->ready)
- dev->ready(dev);
+ if (!dev->running)
+ start_device(dev);
}
}
static void handle_output(unsigned long addr)
{
struct device *i;
- struct virtqueue *vq;
- /* Check each device and virtqueue. */
+ /* Check each device. */
for (i = devices.dev; i; i = i->next) {
+ struct virtqueue *vq;
+
/* Notifications to device descriptors update device status. */
if (from_guest_phys(addr) == i->desc) {
update_device_status(i);
return;
}
- /* Notifications to virtqueues mean output has occurred. */
+ /* Devices *can* be used before status is set to DRIVER_OK. */
for (vq = i->vq; vq; vq = vq->next) {
- if (vq->config.pfn != addr/getpagesize())
+ if (addr != vq->config.pfn*getpagesize())
continue;
-
- /* Guest should acknowledge (and set features!) before
- * using the device. */
- if (i->desc->status == 0) {
- warnx("%s gave early output", i->name);
- return;
- }
-
- if (strcmp(vq->dev->name, "console") != 0)
- verbose("Output to %s\n", vq->dev->name);
- if (vq->handle_output)
- vq->handle_output(vq, false);
+ if (i->running)
+ errx(1, "Notification on running %s", i->name);
+ start_device(i);
return;
}
}
strnlen(from_guest_phys(addr), guest_limit - addr));
}
-static void handle_timeout(void)
-{
- char buf[32];
- struct device *i;
- struct virtqueue *vq;
-
- /* Clear the pipe */
- read(timeoutpipe[0], buf, sizeof(buf));
-
- /* Check each device and virtqueue: flush blocked ones. */
- for (i = devices.dev; i; i = i->next) {
- for (vq = i->vq; vq; vq = vq->next) {
- if (!vq->blocked)
- continue;
-
- vq->vring.used->flags &= ~VRING_USED_F_NO_NOTIFY;
- vq->blocked = false;
- if (vq->handle_output)
- vq->handle_output(vq, true);
- }
- }
-}
-
-/* This is called when the Waker wakes us up: check for incoming file
- * descriptors. */
-static void handle_input(void)
-{
- /* select() wants a zeroed timeval to mean "don't wait". */
- struct timeval poll = { .tv_sec = 0, .tv_usec = 0 };
-
- for (;;) {
- struct device *i;
- fd_set fds = devices.infds;
- int num;
-
- num = select(devices.max_infd+1, &fds, NULL, NULL, &poll);
- /* Could get interrupted */
- if (num < 0)
- continue;
- /* If nothing is ready, we're done. */
- if (num == 0)
- break;
-
- /* Otherwise, call the device(s) which have readable file
- * descriptors and a method of handling them. */
- for (i = devices.dev; i; i = i->next) {
- if (i->handle_input && FD_ISSET(i->fd, &fds)) {
- if (i->handle_input(i))
- continue;
-
- /* If handle_input() returns false, it means we
- * should no longer service it. Networking and
- * console do this when there's no input
- * buffers to deliver into. Console also uses
- * it when it discovers that stdin is closed. */
- FD_CLR(i->fd, &devices.infds);
- }
- }
-
- /* Is this the timeout fd? */
- if (FD_ISSET(timeoutpipe[0], &fds))
- handle_timeout();
- }
-}
-
/*L:190
* Device Setup
*
/* Each device descriptor is followed by the description of its virtqueues. We
* specify how many descriptors the virtqueue is to have. */
static void add_virtqueue(struct device *dev, unsigned int num_descs,
- void (*handle_output)(struct virtqueue *, bool))
+ void (*service)(struct virtqueue *))
{
unsigned int pages;
struct virtqueue **i, *vq = malloc(sizeof(*vq));
vq->next = NULL;
vq->last_avail_idx = 0;
vq->dev = dev;
- vq->blocked = false;
+ vq->service = service;
+ vq->thread = (pid_t)-1;
/* Initialize the configuration. */
vq->config.num = num_descs;
* second. */
for (i = &dev->vq; *i; i = &(*i)->next);
*i = vq;
-
- /* Set the routine to call when the Guest does something to this
- * virtqueue. */
- vq->handle_output = handle_output;
-
- /* As an optimization, set the advisory "Don't Notify Me" flag if we
- * don't have a handler */
- if (!handle_output)
- vq->vring.used->flags = VRING_USED_F_NO_NOTIFY;
}
/* The first half of the feature bitmask is for us to advertise features. The
* calling new_dev_desc() to allocate the descriptor and device memory.
*
* See what I mean about userspace being boring? */
-static struct device *new_device(const char *name, u16 type, int fd,
- bool (*handle_input)(struct device *))
+static struct device *new_device(const char *name, u16 type)
{
struct device *dev = malloc(sizeof(*dev));
/* Now we populate the fields one at a time. */
- dev->fd = fd;
- /* If we have an input handler for this file descriptor, then we add it
- * to the device_list's fdset and maxfd. */
- if (handle_input)
- add_device_fd(dev->fd);
dev->desc = new_dev_desc(type);
- dev->handle_input = handle_input;
dev->name = name;
dev->vq = NULL;
- dev->ready = NULL;
dev->feature_len = 0;
dev->num_vq = 0;
+ dev->running = false;
/* Append to device list. Prepending to a single-linked list is
* easier, but the user expects the devices to be arranged on the bus
* raw input stream to the Guest. */
term.c_lflag &= ~(ISIG|ICANON|ECHO);
tcsetattr(STDIN_FILENO, TCSANOW, &term);
- /* If we exit gracefully, the original settings will be
- * restored so the user can see what they're typing. */
- atexit(restore_term);
}
- dev = new_device("console", VIRTIO_ID_CONSOLE,
- STDIN_FILENO, handle_console_input);
+ dev = new_device("console", VIRTIO_ID_CONSOLE);
+
/* We store the console state in dev->priv, and initialize it. */
dev->priv = malloc(sizeof(struct console_abort));
((struct console_abort *)dev->priv)->count = 0;
* they put something the input queue, we make sure we're listening to
* stdin. When they put something in the output queue, we write it to
* stdout. */
- add_virtqueue(dev, VIRTQUEUE_NUM, enable_fd);
- add_virtqueue(dev, VIRTQUEUE_NUM, handle_console_output);
+ add_virtqueue(dev, VIRTQUEUE_NUM, console_input);
+ add_virtqueue(dev, VIRTQUEUE_NUM, console_output);
- verbose("device %u: console\n", devices.device_num++);
+ verbose("device %u: console\n", ++devices.device_num);
}
/*:*/
-static void timeout_alarm(int sig)
-{
- write(timeoutpipe[1], "", 1);
-}
-
-static void setup_timeout(void)
-{
- if (pipe(timeoutpipe) != 0)
- err(1, "Creating timeout pipe");
-
- if (fcntl(timeoutpipe[1], F_SETFL,
- fcntl(timeoutpipe[1], F_GETFL) | O_NONBLOCK) != 0)
- err(1, "Making timeout pipe nonblocking");
-
- add_device_fd(timeoutpipe[0]);
- signal(SIGALRM, timeout_alarm);
-}
-
/*M:010 Inter-guest networking is an interesting area. Simplest is to have a
* --sharenet=<name> option which opens or creates a named pipe. This can be
* used to send packets to another guest in a 1:1 manner.
static void setup_tun_net(char *arg)
{
struct device *dev;
- int netfd, ipfd;
+ struct net_info *net_info = malloc(sizeof(*net_info));
+ int ipfd;
u32 ip = INADDR_ANY;
bool bridging = false;
char tapif[IFNAMSIZ], *p;
struct virtio_net_config conf;
- netfd = get_tun_device(tapif);
+ net_info->tunfd = get_tun_device(tapif);
/* First we create a new network device. */
- dev = new_device("net", VIRTIO_ID_NET, netfd, handle_tun_input);
+ dev = new_device("net", VIRTIO_ID_NET);
+ dev->priv = net_info;
/* Network devices need a receive and a send queue, just like
* console. */
- add_virtqueue(dev, VIRTQUEUE_NUM, net_enable_fd);
- add_virtqueue(dev, VIRTQUEUE_NUM, handle_net_output);
+ add_virtqueue(dev, VIRTQUEUE_NUM, net_input);
+ add_virtqueue(dev, VIRTQUEUE_NUM, net_output);
/* We need a socket to perform the magic network ioctls to bring up the
* tap interface, connect to the bridge etc. Any socket will do! */
* Remember that the block device is handled by a separate I/O thread. We head
* straight into the core of that thread here:
*/
-static bool service_io(struct device *dev)
+static void blk_request(struct virtqueue *vq)
{
- struct vblk_info *vblk = dev->priv;
+ struct vblk_info *vblk = vq->dev->priv;
unsigned int head, out_num, in_num, wlen;
int ret;
u8 *in;
struct virtio_blk_outhdr *out;
- struct iovec iov[dev->vq->vring.num];
+ struct iovec iov[vq->vring.num];
off64_t off;
- /* See if there's a request waiting. If not, nothing to do. */
- head = get_vq_desc(dev->vq, iov, &out_num, &in_num);
- if (head == dev->vq->vring.num)
- return false;
+ /* Get the next request. */
+ head = wait_for_vq_desc(vq, iov, &out_num, &in_num);
/* Every block request should contain at least one output buffer
* (detailing the location on disk and the type of request) and one
if (out->type & VIRTIO_BLK_T_BARRIER)
fdatasync(vblk->fd);
- /* We can't trigger an IRQ, because we're not the Launcher. It does
- * that when we tell it we're done. */
- add_used(dev->vq, head, wlen);
- return true;
-}
-
-/* This is the thread which actually services the I/O. */
-static int io_thread(void *_dev)
-{
- struct device *dev = _dev;
- struct vblk_info *vblk = dev->priv;
- char c;
-
- /* Close other side of workpipe so we get 0 read when main dies. */
- close(vblk->workpipe[1]);
- /* Close the other side of the done_fd pipe. */
- close(dev->fd);
-
- /* When this read fails, it means Launcher died, so we follow. */
- while (read(vblk->workpipe[0], &c, 1) == 1) {
- /* We acknowledge each request immediately to reduce latency,
- * rather than waiting until we've done them all. I haven't
- * measured to see if it makes any difference.
- *
- * That would be an interesting test, wouldn't it? You could
- * also try having more than one I/O thread. */
- while (service_io(dev))
- write(vblk->done_fd, &c, 1);
- }
- return 0;
-}
-
-/* Now we've seen the I/O thread, we return to the Launcher to see what happens
- * when that thread tells us it's completed some I/O. */
-static bool handle_io_finish(struct device *dev)
-{
- char c;
-
- /* If the I/O thread died, presumably it printed the error, so we
- * simply exit. */
- if (read(dev->fd, &c, 1) != 1)
- exit(1);
-
- /* It did some work, so trigger the irq. */
- trigger_irq(dev->vq);
- return true;
-}
-
-/* When the Guest submits some I/O, we just need to wake the I/O thread. */
-static void handle_virtblk_output(struct virtqueue *vq, bool timeout)
-{
- struct vblk_info *vblk = vq->dev->priv;
- char c = 0;
-
- /* Wake up I/O thread and tell it to go to work! */
- if (write(vblk->workpipe[1], &c, 1) != 1)
- /* Presumably it indicated why it died. */
- exit(1);
+ add_used_and_trigger(vq, head, wlen);
}
/*L:198 This actually sets up a virtual block device. */
static void setup_block_file(const char *filename)
{
- int p[2];
struct device *dev;
struct vblk_info *vblk;
- void *stack;
struct virtio_blk_config conf;
- /* This is the pipe the I/O thread will use to tell us I/O is done. */
- pipe(p);
-
/* The device responds to return from I/O thread. */
- dev = new_device("block", VIRTIO_ID_BLOCK, p[0], handle_io_finish);
+ dev = new_device("block", VIRTIO_ID_BLOCK);
/* The device has one virtqueue, where the Guest places requests. */
- add_virtqueue(dev, VIRTQUEUE_NUM, handle_virtblk_output);
+ add_virtqueue(dev, VIRTQUEUE_NUM, blk_request);
/* Allocate the room for our own bookkeeping */
vblk = dev->priv = malloc(sizeof(*vblk));
set_config(dev, sizeof(conf), &conf);
- /* The I/O thread writes to this end of the pipe when done. */
- vblk->done_fd = p[1];
-
- /* This is the second pipe, which is how we tell the I/O thread about
- * more work. */
- pipe(vblk->workpipe);
-
- /* Create stack for thread and run it. Since stack grows upwards, we
- * point the stack pointer to the end of this region. */
- stack = malloc(32768);
- /* SIGCHLD - We dont "wait" for our cloned thread, so prevent it from
- * becoming a zombie. */
- if (clone(io_thread, stack + 32768, CLONE_VM | SIGCHLD, dev) == -1)
- err(1, "Creating clone");
-
- /* We don't need to keep the I/O thread's end of the pipes open. */
- close(vblk->done_fd);
- close(vblk->workpipe[0]);
-
verbose("device %u: virtblock %llu sectors\n",
- devices.device_num, le64_to_cpu(conf.capacity));
+ ++devices.device_num, le64_to_cpu(conf.capacity));
}
+struct rng_info {
+ int rfd;
+};
+
/* Our random number generator device reads from /dev/random into the Guest's
* input buffers. The usual case is that the Guest doesn't want random numbers
* and so has no buffers although /dev/random is still readable, whereas
* console is the reverse.
*
* The same logic applies, however. */
-static bool handle_rng_input(struct device *dev)
+static void rng_input(struct virtqueue *vq)
{
int len;
unsigned int head, in_num, out_num, totlen = 0;
- struct iovec iov[dev->vq->vring.num];
+ struct rng_info *rng_info = vq->dev->priv;
+ struct iovec iov[vq->vring.num];
/* First we need a buffer from the Guests's virtqueue. */
- head = get_vq_desc(dev->vq, iov, &out_num, &in_num);
-
- /* If they're not ready for input, stop listening to this file
- * descriptor. We'll start again once they add an input buffer. */
- if (head == dev->vq->vring.num)
- return false;
-
+ head = wait_for_vq_desc(vq, iov, &out_num, &in_num);
if (out_num)
errx(1, "Output buffers in rng?");
* it reads straight into the Guest's buffer. We loop to make sure we
* fill it. */
while (!iov_empty(iov, in_num)) {
- len = readv(dev->fd, iov, in_num);
+ len = readv(rng_info->rfd, iov, in_num);
if (len <= 0)
err(1, "Read from /dev/random gave %i", len);
iov_consume(iov, in_num, len);
}
/* Tell the Guest about the new input. */
- add_used_and_trigger(dev->vq, head, totlen);
-
- /* Everything went OK! */
- return true;
+ add_used_and_trigger(vq, head, totlen);
}
/* And this creates a "hardware" random number device for the Guest. */
static void setup_rng(void)
{
struct device *dev;
- int fd;
+ struct rng_info *rng_info = malloc(sizeof(*rng_info));
- fd = open_or_die("/dev/random", O_RDONLY);
+ rng_info->rfd = open_or_die("/dev/random", O_RDONLY);
/* The device responds to return from I/O thread. */
- dev = new_device("rng", VIRTIO_ID_RNG, fd, handle_rng_input);
+ dev = new_device("rng", VIRTIO_ID_RNG);
+ dev->priv = rng_info;
/* The device has one virtqueue, where the Guest places inbufs. */
- add_virtqueue(dev, VIRTQUEUE_NUM, enable_fd);
+ add_virtqueue(dev, VIRTQUEUE_NUM, rng_input);
verbose("device %u: rng\n", devices.device_num++);
}
for (i = 3; i < FD_SETSIZE; i++)
close(i);
- /* The exec automatically gets rid of the I/O and Waker threads. */
+ /* Reset all the devices (kills all threads). */
+ cleanup_devices();
+
execv(main_args[0], main_args);
err(1, "Could not exec %s", main_args[0]);
}
static void __attribute__((noreturn)) run_guest(void)
{
for (;;) {
- unsigned long args[] = { LHREQ_BREAK, 0 };
unsigned long notify_addr;
int readval;
if (readval == sizeof(notify_addr)) {
verbose("Notify on address %#lx\n", notify_addr);
handle_output(notify_addr);
- continue;
/* ENOENT means the Guest died. Reading tells us why. */
} else if (errno == ENOENT) {
char reason[1024] = { 0 };
/* ERESTART means that we need to reboot the guest */
} else if (errno == ERESTART) {
restart_guest();
- /* EAGAIN means a signal (timeout).
- * Anything else means a bug or incompatible change. */
- } else if (errno != EAGAIN)
+ /* Anything else means a bug or incompatible change. */
+ } else
err(1, "Running guest failed");
-
- /* Only service input on thread for CPU 0. */
- if (cpu_id != 0)
- continue;
-
- /* Service input, then unset the BREAK to release the Waker. */
- handle_input();
- if (pwrite(lguest_fd, args, sizeof(args), cpu_id) < 0)
- err(1, "Resetting break");
}
}
/*L:240
/* Save the args: we "reboot" by execing ourselves again. */
main_args = argv;
- /* We don't "wait" for the children, so prevent them from becoming
- * zombies. */
- signal(SIGCHLD, SIG_IGN);
- /* First we initialize the device list. Since console and network
- * device receive input from a file descriptor, we keep an fdset
- * (infds) and the maximum fd number (max_infd) with the head of the
- * list. We also keep a pointer to the last device. Finally, we keep
- * the next interrupt number to use for devices (1: remember that 0 is
- * used by the timer). */
- FD_ZERO(&devices.infds);
- devices.max_infd = -1;
+ /* First we initialize the device list. We keep a pointer to the last
+ * device, and the next interrupt number to use for devices (1:
+ * remember that 0 is used by the timer). */
devices.lastdev = NULL;
devices.next_irq = 1;
/* We always have a console device */
setup_console();
- /* We can timeout waiting for Guest network transmit. */
- setup_timeout();
-
/* Now we load the kernel */
start = load_kernel(open_or_die(argv[optind+1], O_RDONLY));
* /dev/lguest file descriptor. */
tell_kernel(start);
- /* We clone off a thread, which wakes the Launcher whenever one of the
- * input file descriptors needs attention. We call this the Waker, and
- * we'll cover it in a moment. */
- setup_waker();
+ /* Ensure that we terminate if a child dies. */
+ signal(SIGCHLD, kill_launcher);
+
+ /* If we exit via err(), this kills all the threads, restores tty. */
+ atexit(cleanup_devices);
/* Finally, run the Guest. This doesn't return. */
run_guest();
git://ftp.safe.ca / safe / jmp / linux-2.6 / commitdiff