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>
diff --git a/include/asm-x86/lguest_hcall.h b/include/asm-x86/lguest_hcall.h
index f948491..9c5092b 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 8beb291..175e63f 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 c41fd48..697104d 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