From ec04b13f67be3c90b38c625f4b8bdfea54c1ff60 Mon Sep 17 00:00:00 2001 From: Balaji Rao Date: Fri, 28 Dec 2007 14:26:24 +0530 Subject: lguest: Reboot support Reboot Implemented (Prevent fd leak, fix style and fix documentation --RR) Signed-off-by: Balaji Rao Signed-off-by: Rusty Russell --- Documentation/lguest/lguest.c | 32 ++++++++++++++++++++++++++++++-- 1 file changed, 30 insertions(+), 2 deletions(-) (limited to 'Documentation/lguest/lguest.c') diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c index 9b0e322118b..86cac3e622a 100644 --- a/Documentation/lguest/lguest.c +++ b/Documentation/lguest/lguest.c @@ -153,6 +153,9 @@ struct virtqueue void (*handle_output)(int fd, struct virtqueue *me); }; +/* Remember the arguments to the program so we can "reboot" */ +static char **main_args; + /* Since guest is UP and we don't run at the same time, we don't need barriers. * But I include them in the code in case others copy it. */ #define wmb() @@ -1489,7 +1492,9 @@ static void setup_block_file(const char *filename) /* Create stack for thread and run it */ stack = malloc(32768); - if (clone(io_thread, stack + 32768, CLONE_VM, dev) == -1) + /* 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. */ @@ -1499,7 +1504,21 @@ static void setup_block_file(const char *filename) verbose("device %u: virtblock %llu sectors\n", devices.device_num, cap); } -/* That's the end of device setup. */ +/* That's the end of device setup. :*/ + +/* Reboot */ +static void __attribute__((noreturn)) restart_guest(void) +{ + unsigned int i; + + /* Closing pipes causes the waker thread and io_threads to die, and + * closing /dev/lguest cleans up the Guest. Since we don't track all + * open fds, we simply close everything beyond stderr. */ + for (i = 3; i < FD_SETSIZE; i++) + close(i); + execv(main_args[0], main_args); + err(1, "Could not exec %s", main_args[0]); +} /*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. */ @@ -1523,6 +1542,9 @@ static void __attribute__((noreturn)) run_guest(int lguest_fd) char reason[1024] = { 0 }; read(lguest_fd, reason, sizeof(reason)-1); errx(1, "%s", reason); + /* ERESTART means that we need to reboot the guest */ + } else if (errno == ERESTART) { + restart_guest(); /* EAGAIN means the Waker wanted us to look at some input. * Anything else means a bug or incompatible change. */ } else if (errno != EAGAIN) @@ -1571,6 +1593,12 @@ int main(int argc, char *argv[]) /* If they specify an initrd file to load. */ const char *initrd_name = NULL; + /* 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 -- cgit v1.2.3-70-g09d2 From e3283fa0cc5c4f9bde52339a40da89297e51b481 Mon Sep 17 00:00:00 2001 From: Glauber de Oliveira Costa Date: Mon, 7 Jan 2008 11:05:23 -0200 Subject: lguest: adapt launcher to per-cpuness This patch makes uses of pread() and pwrite() in lguest launcher to communicate the vcpu id to the lguest driver. The id is kept in a thread variable, which means we'll span in the future, vcpus as threads. But right now, only the infrastructure is out there. Signed-off-by: Glauber de Oliveira Costa Signed-off-by: Rusty Russell --- Documentation/lguest/lguest.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) (limited to 'Documentation/lguest/lguest.c') diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c index 86cac3e622a..6c8a2386cd5 100644 --- a/Documentation/lguest/lguest.c +++ b/Documentation/lguest/lguest.c @@ -79,6 +79,9 @@ static void *guest_base; /* The maximum guest physical address allowed, and maximum possible. */ static unsigned long guest_limit, guest_max; +/* a per-cpu variable indicating whose vcpu is currently running */ +static unsigned int __thread cpu_id; + /* This is our list of devices. */ struct device_list { @@ -557,7 +560,7 @@ static void wake_parent(int pipefd, int lguest_fd) else FD_CLR(-fd - 1, &devices.infds); } else /* Send LHREQ_BREAK command. */ - write(lguest_fd, args, sizeof(args)); + pwrite(lguest_fd, args, sizeof(args), cpu_id); } } @@ -1530,7 +1533,8 @@ static void __attribute__((noreturn)) run_guest(int lguest_fd) int readval; /* We read from the /dev/lguest device to run the Guest. */ - readval = read(lguest_fd, ¬ify_addr, sizeof(notify_addr)); + readval = pread(lguest_fd, ¬ify_addr, + sizeof(notify_addr), cpu_id); /* One unsigned long means the Guest did HCALL_NOTIFY */ if (readval == sizeof(notify_addr)) { @@ -1540,7 +1544,7 @@ static void __attribute__((noreturn)) run_guest(int lguest_fd) /* ENOENT means the Guest died. Reading tells us why. */ } else if (errno == ENOENT) { char reason[1024] = { 0 }; - read(lguest_fd, reason, sizeof(reason)-1); + pread(lguest_fd, reason, sizeof(reason)-1, cpu_id); errx(1, "%s", reason); /* ERESTART means that we need to reboot the guest */ } else if (errno == ERESTART) { @@ -1550,9 +1554,13 @@ static void __attribute__((noreturn)) run_guest(int lguest_fd) } else if (errno != EAGAIN) 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(lguest_fd); - if (write(lguest_fd, args, sizeof(args)) < 0) + if (pwrite(lguest_fd, args, sizeof(args), cpu_id) < 0) err(1, "Resetting break"); } } @@ -1610,6 +1618,7 @@ int main(int argc, char *argv[]) devices.lastdev = &devices.dev; devices.next_irq = 1; + cpu_id = 0; /* We need to know how much memory so we can set up the device * descriptor and memory pages for the devices as we parse the command * line. So we quickly look through the arguments to find the amount -- cgit v1.2.3-70-g09d2