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path: root/drivers/lguest/lguest_user.c
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Diffstat (limited to 'drivers/lguest/lguest_user.c')
-rw-r--r--drivers/lguest/lguest_user.c23
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.