diff options
Diffstat (limited to 'drivers/lguest/lguest_user.c')
| -rw-r--r-- | drivers/lguest/lguest_user.c | 23 |
1 files changed, 12 insertions, 11 deletions
diff --git a/drivers/lguest/lguest_user.c b/drivers/lguest/lguest_user.c index ee405b38383..9d716fa42ca 100644 --- a/drivers/lguest/lguest_user.c +++ b/drivers/lguest/lguest_user.c @@ -8,20 +8,22 @@ #include <linux/fs.h> #include "lg.h" -/*L:315 To force the Guest to stop running and return to the Launcher, the - * Waker sets writes LHREQ_BREAK and the value "1" to /dev/lguest. The - * Launcher then writes LHREQ_BREAK and "0" to release the Waker. */ +/*L:055 When something happens, the Waker process needs a way to stop the + * kernel running the Guest and return to the Launcher. So the Waker writes + * LHREQ_BREAK and the value "1" to /dev/lguest to do this. Once the Launcher + * has done whatever needs attention, it writes LHREQ_BREAK and "0" to release + * the Waker. */ static int break_guest_out(struct lguest *lg, const unsigned long __user *input) { unsigned long on; - /* Fetch whether they're turning break on or off.. */ + /* Fetch whether they're turning break on or off. */ if (get_user(on, input) != 0) return -EFAULT; if (on) { lg->break_out = 1; - /* Pop it out (may be running on different CPU) */ + /* Pop it out of the Guest (may be running on different CPU) */ wake_up_process(lg->tsk); /* Wait for them to reset it */ return wait_event_interruptible(lg->break_wq, !lg->break_out); @@ -58,7 +60,7 @@ static ssize_t read(struct file *file, char __user *user, size_t size,loff_t*o) if (!lg) return -EINVAL; - /* If you're not the task which owns the guest, go away. */ + /* If you're not the task which owns the Guest, go away. */ if (current != lg->tsk) return -EPERM; @@ -92,8 +94,8 @@ static ssize_t read(struct file *file, char __user *user, size_t size,loff_t*o) * base: The start of the Guest-physical memory inside the Launcher memory. * * pfnlimit: The highest (Guest-physical) page number the Guest should be - * allowed to access. The Launcher has to live in Guest memory, so it sets - * this to ensure the Guest can't reach it. + * allowed to access. The Guest memory lives inside the Launcher, so it sets + * this to ensure the Guest can only reach its own memory. * * pgdir: The (Guest-physical) address of the top of the initial Guest * pagetables (which are set up by the Launcher). @@ -189,7 +191,7 @@ unlock: } /*L:010 The first operation the Launcher does must be a write. All writes - * start with a 32 bit number: for the first write this must be + * start with an unsigned long number: for the first write this must be * LHREQ_INITIALIZE to set up the Guest. After that the Launcher can use * writes of other values to send interrupts. */ static ssize_t write(struct file *file, const char __user *in, @@ -275,8 +277,7 @@ static int close(struct inode *inode, struct file *file) * The Launcher is the Host userspace program which sets up, runs and services * the Guest. In fact, many comments in the Drivers which refer to "the Host" * doing things are inaccurate: the Launcher does all the device handling for - * the Guest. The Guest can't tell what's done by the the Launcher and what by - * the Host. + * the Guest, but the Guest can't know that. * * Just to confuse you: to the Host kernel, the Launcher *is* the Guest and we * shall see more of that later. |