diff options
Diffstat (limited to 'Documentation/lguest/lguest.c')
| -rw-r--r-- | Documentation/lguest/lguest.c | 102 |
1 files changed, 47 insertions, 55 deletions
diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c index e65d6cbf241..1a2b906a3ae 100644 --- a/Documentation/lguest/lguest.c +++ b/Documentation/lguest/lguest.c @@ -79,7 +79,6 @@ static bool verbose; /* File descriptors for the Waker. */ struct { int pipe[2]; - int lguest_fd; } waker_fds; /* The pointer to the start of guest memory. */ @@ -89,6 +88,8 @@ 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; /* a per-cpu variable indicating whose vcpu is currently running */ static unsigned int __thread cpu_id; @@ -139,7 +140,7 @@ struct device /* If handle_input is set, it wants to be called when this file * descriptor is ready. */ int fd; - bool (*handle_input)(int fd, struct device *me); + bool (*handle_input)(struct device *me); /* Any queues attached to this device */ struct virtqueue *vq; @@ -169,7 +170,7 @@ struct virtqueue u16 last_avail_idx; /* The routine to call when the Guest pings us, or timeout. */ - void (*handle_output)(int fd, struct virtqueue *me, bool timeout); + void (*handle_output)(struct virtqueue *me, bool timeout); /* Outstanding buffers */ unsigned int inflight; @@ -509,21 +510,16 @@ static void concat(char *dst, char *args[]) * saw the arguments it expects when we looked at initialize() in lguest_user.c: * the base of Guest "physical" memory, the top physical page to allow and the * entry point for the Guest. */ -static int tell_kernel(unsigned long start) +static void tell_kernel(unsigned long start) { unsigned long args[] = { LHREQ_INITIALIZE, (unsigned long)guest_base, guest_limit / getpagesize(), start }; - int fd; - verbose("Guest: %p - %p (%#lx)\n", guest_base, guest_base + guest_limit, guest_limit); - fd = open_or_die("/dev/lguest", O_RDWR); - if (write(fd, args, sizeof(args)) < 0) + lguest_fd = open_or_die("/dev/lguest", O_RDWR); + if (write(lguest_fd, args, sizeof(args)) < 0) err(1, "Writing to /dev/lguest"); - - /* We return the /dev/lguest file descriptor to control this Guest */ - return fd; } /*:*/ @@ -583,21 +579,18 @@ static int waker(void *unused) } /* Send LHREQ_BREAK command to snap the Launcher out of it. */ - pwrite(waker_fds.lguest_fd, args, sizeof(args), cpu_id); + 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(int lguest_fd) +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"); - /* Waker also needs to know the lguest fd */ - waker_fds.lguest_fd = lguest_fd; - if (clone(waker, malloc(4096) + 4096, CLONE_VM | SIGCHLD, NULL) == -1) err(1, "Creating Waker"); } @@ -727,7 +720,7 @@ static void add_used(struct virtqueue *vq, unsigned int head, int len) } /* This actually sends the interrupt for this virtqueue */ -static void trigger_irq(int fd, struct virtqueue *vq) +static void trigger_irq(struct virtqueue *vq) { unsigned long buf[] = { LHREQ_IRQ, vq->config.irq }; @@ -737,16 +730,15 @@ static void trigger_irq(int fd, struct virtqueue *vq) return; /* Send the Guest an interrupt tell them we used something up. */ - if (write(fd, buf, sizeof(buf)) != 0) + if (write(lguest_fd, buf, sizeof(buf)) != 0) err(1, "Triggering irq %i", vq->config.irq); } /* And here's the combo meal deal. Supersize me! */ -static void add_used_and_trigger(int fd, struct virtqueue *vq, - unsigned int head, int len) +static void add_used_and_trigger(struct virtqueue *vq, unsigned head, int len) { add_used(vq, head, len); - trigger_irq(fd, vq); + trigger_irq(vq); } /* @@ -770,7 +762,7 @@ struct console_abort }; /* This is the routine which handles console input (ie. stdin). */ -static bool handle_console_input(int fd, struct device *dev) +static bool handle_console_input(struct device *dev) { int len; unsigned int head, in_num, out_num; @@ -804,7 +796,7 @@ static bool handle_console_input(int fd, struct device *dev) } /* Tell the Guest about the new input. */ - add_used_and_trigger(fd, dev->vq, head, len); + add_used_and_trigger(dev->vq, head, len); /* Three ^C within one second? Exit. * @@ -824,7 +816,7 @@ static bool handle_console_input(int fd, struct device *dev) close(waker_fds.pipe[1]); /* Just in case Waker is blocked in BREAK, send * unbreak now. */ - write(fd, args, sizeof(args)); + write(lguest_fd, args, sizeof(args)); exit(2); } abort->count = 0; @@ -839,7 +831,7 @@ static bool handle_console_input(int fd, struct device *dev) /* Handling output for console is simple: we just get all the output buffers * and write them to stdout. */ -static void handle_console_output(int fd, struct virtqueue *vq, bool timeout) +static void handle_console_output(struct virtqueue *vq, bool timeout) { unsigned int head, out, in; int len; @@ -850,7 +842,7 @@ static void handle_console_output(int fd, struct virtqueue *vq, bool timeout) if (in) errx(1, "Input buffers in output queue?"); len = writev(STDOUT_FILENO, iov, out); - add_used_and_trigger(fd, vq, head, len); + add_used_and_trigger(vq, head, len); } } @@ -879,7 +871,7 @@ static void block_vq(struct virtqueue *vq) * and write them (ignoring the first element) to this device's file descriptor * (/dev/net/tun). */ -static void handle_net_output(int fd, struct virtqueue *vq, bool timeout) +static void handle_net_output(struct virtqueue *vq, bool timeout) { unsigned int head, out, in, num = 0; int len; @@ -893,7 +885,7 @@ static void handle_net_output(int fd, struct virtqueue *vq, bool timeout) len = writev(vq->dev->fd, iov, out); if (len < 0) err(1, "Writing network packet to tun"); - add_used_and_trigger(fd, vq, head, len); + add_used_and_trigger(vq, head, len); num++; } @@ -917,7 +909,7 @@ static void handle_net_output(int fd, struct virtqueue *vq, bool timeout) /* This is where we handle a packet coming in from the tun device to our * Guest. */ -static bool handle_tun_input(int fd, struct device *dev) +static bool handle_tun_input(struct device *dev) { unsigned int head, in_num, out_num; int len; @@ -946,7 +938,7 @@ static bool handle_tun_input(int fd, struct device *dev) err(1, "reading network"); /* Tell the Guest about the new packet. */ - add_used_and_trigger(fd, dev->vq, head, len); + add_used_and_trigger(dev->vq, head, len); verbose("tun input packet len %i [%02x %02x] (%s)\n", len, ((u8 *)iov[1].iov_base)[0], ((u8 *)iov[1].iov_base)[1], @@ -959,18 +951,18 @@ static bool handle_tun_input(int fd, struct device *dev) /*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(int fd, struct virtqueue *vq, bool timeout) +static void enable_fd(struct virtqueue *vq, bool timeout) { add_device_fd(vq->dev->fd); /* Snap the Waker out of its select loop. */ write(waker_fds.pipe[1], "", 1); } -static void net_enable_fd(int fd, struct virtqueue *vq, bool timeout) +static void net_enable_fd(struct virtqueue *vq, bool timeout) { /* We don't need to know again when Guest refills receive buffer. */ vq->vring.used->flags |= VRING_USED_F_NO_NOTIFY; - enable_fd(fd, vq, timeout); + enable_fd(vq, timeout); } /* When the Guest tells us they updated the status field, we handle it. */ @@ -1011,7 +1003,7 @@ static void update_device_status(struct device *dev) } /* This is the generic routine we call when the Guest uses LHCALL_NOTIFY. */ -static void handle_output(int fd, unsigned long addr) +static void handle_output(unsigned long addr) { struct device *i; struct virtqueue *vq; @@ -1039,7 +1031,7 @@ static void handle_output(int fd, unsigned long addr) if (strcmp(vq->dev->name, "console") != 0) verbose("Output to %s\n", vq->dev->name); if (vq->handle_output) - vq->handle_output(fd, vq, false); + vq->handle_output(vq, false); return; } } @@ -1053,7 +1045,7 @@ static void handle_output(int fd, unsigned long addr) strnlen(from_guest_phys(addr), guest_limit - addr)); } -static void handle_timeout(int fd) +static void handle_timeout(void) { char buf[32]; struct device *i; @@ -1071,14 +1063,14 @@ static void handle_timeout(int fd) vq->vring.used->flags &= ~VRING_USED_F_NO_NOTIFY; vq->blocked = false; if (vq->handle_output) - vq->handle_output(fd, vq, true); + vq->handle_output(vq, true); } } } /* This is called when the Waker wakes us up: check for incoming file * descriptors. */ -static void handle_input(int fd) +static void handle_input(void) { /* select() wants a zeroed timeval to mean "don't wait". */ struct timeval poll = { .tv_sec = 0, .tv_usec = 0 }; @@ -1100,7 +1092,7 @@ static void handle_input(int fd) * 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(fd, i)) + if (i->handle_input(i)) continue; /* If handle_input() returns false, it means we @@ -1114,7 +1106,7 @@ static void handle_input(int fd) /* Is this the timeout fd? */ if (FD_ISSET(timeoutpipe[0], &fds)) - handle_timeout(fd); + handle_timeout(); } } @@ -1163,7 +1155,7 @@ static struct lguest_device_desc *new_dev_desc(u16 type) /* 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)(int, struct virtqueue *, bool)) + void (*handle_output)(struct virtqueue *, bool)) { unsigned int pages; struct virtqueue **i, *vq = malloc(sizeof(*vq)); @@ -1249,7 +1241,7 @@ static void set_config(struct device *dev, unsigned len, const void *conf) * * See what I mean about userspace being boring? */ static struct device *new_device(const char *name, u16 type, int fd, - bool (*handle_input)(int, struct device *)) + bool (*handle_input)(struct device *)) { struct device *dev = malloc(sizeof(*dev)); @@ -1678,7 +1670,7 @@ static int io_thread(void *_dev) /* 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(int fd, struct device *dev) +static bool handle_io_finish(struct device *dev) { char c; @@ -1688,12 +1680,12 @@ static bool handle_io_finish(int fd, struct device *dev) exit(1); /* It did some work, so trigger the irq. */ - trigger_irq(fd, dev->vq); + 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(int fd, struct virtqueue *vq, bool timeout) +static void handle_virtblk_output(struct virtqueue *vq, bool timeout) { struct vblk_info *vblk = vq->dev->priv; char c = 0; @@ -1771,7 +1763,7 @@ static void setup_block_file(const char *filename) * console is the reverse. * * The same logic applies, however. */ -static bool handle_rng_input(int fd, struct device *dev) +static bool handle_rng_input(struct device *dev) { int len; unsigned int head, in_num, out_num, totlen = 0; @@ -1800,7 +1792,7 @@ static bool handle_rng_input(int fd, struct device *dev) } /* Tell the Guest about the new input. */ - add_used_and_trigger(fd, dev->vq, head, totlen); + add_used_and_trigger(dev->vq, head, totlen); /* Everything went OK! */ return true; @@ -1841,7 +1833,7 @@ static void __attribute__((noreturn)) restart_guest(void) /*L:220 Finally we reach the core of the Launcher which runs the Guest, serves * its input and output, and finally, lays it to rest. */ -static void __attribute__((noreturn)) run_guest(int lguest_fd) +static void __attribute__((noreturn)) run_guest(void) { for (;;) { unsigned long args[] = { LHREQ_BREAK, 0 }; @@ -1855,7 +1847,7 @@ static void __attribute__((noreturn)) run_guest(int lguest_fd) /* One unsigned long means the Guest did HCALL_NOTIFY */ if (readval == sizeof(notify_addr)) { verbose("Notify on address %#lx\n", notify_addr); - handle_output(lguest_fd, notify_addr); + handle_output(notify_addr); continue; /* ENOENT means the Guest died. Reading tells us why. */ } else if (errno == ENOENT) { @@ -1875,7 +1867,7 @@ static void __attribute__((noreturn)) run_guest(int lguest_fd) continue; /* Service input, then unset the BREAK to release the Waker. */ - handle_input(lguest_fd); + handle_input(); if (pwrite(lguest_fd, args, sizeof(args), cpu_id) < 0) err(1, "Resetting break"); } @@ -1911,8 +1903,8 @@ int main(int argc, char *argv[]) /* Memory, top-level pagetable, code startpoint and size of the * (optional) initrd. */ unsigned long mem = 0, start, initrd_size = 0; - /* Two temporaries and the /dev/lguest file descriptor. */ - int i, c, lguest_fd; + /* Two temporaries. */ + int i, c; /* The boot information for the Guest. */ struct boot_params *boot; /* If they specify an initrd file to load. */ @@ -2030,15 +2022,15 @@ int main(int argc, char *argv[]) /* We tell the kernel to initialize the Guest: this returns the open * /dev/lguest file descriptor. */ - lguest_fd = tell_kernel(start); + 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(lguest_fd); + setup_waker(); /* Finally, run the Guest. This doesn't return. */ - run_guest(lguest_fd); + run_guest(); } /*:*/ |