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authorLinus Torvalds <torvalds@linux-foundation.org>2008-01-31 09:35:32 +1100
committerLinus Torvalds <torvalds@linux-foundation.org>2008-01-31 09:35:32 +1100
commitd145c7253c8cb2ed8a75a8839621b0bb8f778820 (patch)
treefac21920d149a2cddfdfbde65066ff98935a9c57 /Documentation
parent44c3b59102e3ecc7a01e9811862633e670595e51 (diff)
parent84f12e39c856a8b1ab407f8216ecebaf4204b94d (diff)
downloadlinaro-lsk-d145c7253c8cb2ed8a75a8839621b0bb8f778820.tar.gz
Merge git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus
* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus: (27 commits) lguest: use __PAGE_KERNEL instead of _PAGE_KERNEL lguest: Use explicit includes rateher than indirect lguest: get rid of lg variable assignments lguest: change gpte_addr header lguest: move changed bitmap to lg_cpu lguest: move last_pages to lg_cpu lguest: change last_guest to last_cpu lguest: change spte_addr header lguest: per-vcpu lguest pgdir management lguest: make pending notifications per-vcpu lguest: makes special fields be per-vcpu lguest: per-vcpu lguest task management lguest: replace lguest_arch with lg_cpu_arch. lguest: make registers per-vcpu lguest: make emulate_insn receive a vcpu struct. lguest: map_switcher_in_guest() per-vcpu lguest: per-vcpu interrupt processing. lguest: per-vcpu lguest timers lguest: make hypercalls use the vcpu struct lguest: make write() operation smp aware ... Manual conflict resolved (maybe even correctly, who knows) in drivers/lguest/x86/core.c
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/lguest/lguest.c49
1 files changed, 43 insertions, 6 deletions
diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c
index 9b0e322118b..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
{
@@ -153,6 +156,9 @@ 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()
@@ -554,7 +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);
}
}
@@ -1489,7 +1495,9 @@ 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 +1507,21 @@ 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. */
@@ -1511,7 +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, &notify_addr, sizeof(notify_addr));
+ readval = pread(lguest_fd, &notify_addr,
+ sizeof(notify_addr), cpu_id);
/* One unsigned long means the Guest did HCALL_NOTIFY */
if (readval == sizeof(notify_addr)) {
@@ -1521,16 +1544,23 @@ 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) {
+ 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)
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");
}
}
@@ -1571,6 +1601,12 @@ 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
@@ -1582,6 +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