lguest: documentation update

Went through the documentation doing typo and content fixes.  This
patch contains only comment and whitespace changes.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

3 files changed, 15 insertions, 11 deletions

diff --git a/include/asm-x86/lguest_hcall.h b/include/asm-x86/lguest_hcall.h
index f948491eb56..9c5092b6aa9 100644
--- a/include/asm-x86/lguest_hcall.h
+++ b/include/asm-x86/lguest_hcall.h
@@ -18,12 +18,17 @@
 #define LHCALL_LOAD_TLS		16
 #define LHCALL_NOTIFY		17
 
+#define LGUEST_TRAP_ENTRY 0x1F
+
+#ifndef __ASSEMBLY__
+#include <asm/hw_irq.h>
+
 /*G:031 First, how does our Guest contact the Host to ask for privileged
  * operations?  There are two ways: the direct way is to make a "hypercall",
  * to make requests of the Host Itself.
  *
  * Our hypercall mechanism uses the highest unused trap code (traps 32 and
- * above are used by real hardware interrupts).  Seventeen hypercalls are
+ * above are used by real hardware interrupts).  Fifteen hypercalls are
  * available: the hypercall number is put in the %eax register, and the
  * arguments (when required) are placed in %edx, %ebx and %ecx.  If a return
  * value makes sense, it's returned in %eax.
@@ -31,20 +36,15 @@
  * Grossly invalid calls result in Sudden Death at the hands of the vengeful
  * Host, rather than returning failure.  This reflects Winston Churchill's
  * definition of a gentleman: "someone who is only rude intentionally". */
-#define LGUEST_TRAP_ENTRY 0x1F
-
-#ifndef __ASSEMBLY__
-#include <asm/hw_irq.h>
-
 static inline unsigned long
 hcall(unsigned long call,
       unsigned long arg1, unsigned long arg2, unsigned long arg3)
 {
 	/* "int" is the Intel instruction to trigger a trap. */
 	asm volatile("int $" __stringify(LGUEST_TRAP_ENTRY)
-		       /* The call is in %eax (aka "a"), and can be replaced */
+		       /* The call in %eax (aka "a") might be overwritten */
 		     : "=a"(call)
-		       /* The other arguments are in %eax, %edx, %ebx & %ecx */
+		       /* The arguments are in %eax, %edx, %ebx & %ecx */
 		     : "a"(call), "d"(arg1), "b"(arg2), "c"(arg3)
 		       /* "memory" means this might write somewhere in memory.
 			* This isn't true for all calls, but it's safe to tell
diff --git a/include/linux/lguest.h b/include/linux/lguest.h
index 8beb2913462..175e63f4a8c 100644
--- a/include/linux/lguest.h
+++ b/include/linux/lguest.h
@@ -12,8 +12,8 @@
 #define LG_CLOCK_MAX_DELTA	ULONG_MAX
 
 /*G:032 The second method of communicating with the Host is to via "struct
- * lguest_data".  The Guest's very first hypercall is to tell the Host where
- * this is, and then the Guest and Host both publish information in it. :*/
+ * lguest_data".  Once the Guest's initialization hypercall tells the Host where
+ * this is, the Guest and Host both publish information in it. :*/
 struct lguest_data
 {
 	/* 512 == enabled (same as eflags in normal hardware).  The Guest
diff --git a/include/linux/lguest_launcher.h b/include/linux/lguest_launcher.h
index c41fd483af3..697104da91f 100644
--- a/include/linux/lguest_launcher.h
+++ b/include/linux/lguest_launcher.h
@@ -10,7 +10,11 @@
  * real devices (think of the damage it could do!) we provide virtual devices.
  * We could emulate a PCI bus with various devices on it, but that is a fairly
  * complex burden for the Host and suboptimal for the Guest, so we have our own
- * "lguest" bus and simple drivers.
+ * simple lguest bus and we use "virtio" drivers.  These drivers need a set of
+ * routines from us which will actually do the virtual I/O, but they handle all
+ * the net/block/console stuff themselves.  This means that if we want to add
+ * a new device, we simply need to write a new virtio driver and create support
+ * for it in the Launcher: this code won't need to change.
  *
  * Devices are described by a simplified ID, a status byte, and some "config"
  * bytes which describe this device's configuration.  This is placed by the