kernel-ark/drivers/lguest
Andi Kleen ab144f5ec6 i386: Make patching more robust, fix paravirt issue
Commit 19d36ccdc3 "x86: Fix alternatives
and kprobes to remap write-protected kernel text" uses code which is
being patched for patching.

In particular, paravirt_ops does patching in two stages: first it
calls paravirt_ops.patch, then it fills any remaining instructions
with nop_out().  nop_out calls text_poke() which calls
lookup_address() which calls pgd_val() (aka paravirt_ops.pgd_val):
that call site is one of the places we patch.

If we always do patching as one single call to text_poke(), we only
need make sure we're not patching the memcpy in text_poke itself.
This means the prototype to paravirt_ops.patch needs to change, to
marshal the new code into a buffer rather than patching in place as it
does now.  It also means all patching goes through text_poke(), which
is known to be safe (apply_alternatives is also changed to make a
single patch).

AK: fix compilation on x86-64 (bad rusty!)
AK: fix boot on x86-64 (sigh)
AK: merged with other patches

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-08-11 15:58:13 -07:00
..
core.c lguest: Fix Malicious Guest GDT Host Crash 2007-08-09 08:14:56 -07:00
hypercalls.c Provide timespec to guests rather than jiffies clock. 2007-07-28 19:54:33 -07:00
interrupts_and_traps.c lguest: Fix Malicious Guest GDT Host Crash 2007-08-09 08:14:56 -07:00
io.c lguest: documentation VII: FIXMEs 2007-07-26 11:35:17 -07:00
Kconfig Enable lguest drivers in Kconfig 2007-08-06 18:21:15 -07:00
lg.h Provide timespec to guests rather than jiffies clock. 2007-07-28 19:54:33 -07:00
lguest_asm.S lguest: documentation VII: FIXMEs 2007-07-26 11:35:17 -07:00
lguest_bus.c lguest files should explicitly include asm/paravirt.h 2007-08-11 15:47:42 -07:00
lguest_user.c lguest: documentation IV: Launcher 2007-07-26 11:35:17 -07:00
lguest.c i386: Make patching more robust, fix paravirt issue 2007-08-11 15:58:13 -07:00
Makefile lguest: documentation I: Preparation 2007-07-26 11:35:16 -07:00
page_tables.c lguest: documentation VII: FIXMEs 2007-07-26 11:35:17 -07:00
README lguest: documentation I: Preparation 2007-07-26 11:35:16 -07:00
segments.c lguest: Fix Malicious Guest GDT Host Crash 2007-08-09 08:14:56 -07:00
switcher.S lguest: Fix Malicious Guest GDT Host Crash 2007-08-09 08:14:56 -07:00

Welcome, friend reader, to lguest.

Lguest is an adventure, with you, the reader, as Hero.  I can't think of many
5000-line projects which offer both such capability and glimpses of future
potential; it is an exciting time to be delving into the source!

But be warned; this is an arduous journey of several hours or more!  And as we
know, all true Heroes are driven by a Noble Goal.  Thus I offer a Beer (or
equivalent) to anyone I meet who has completed this documentation.

So get comfortable and keep your wits about you (both quick and humorous).
Along your way to the Noble Goal, you will also gain masterly insight into
lguest, and hypervisors and x86 virtualization in general.

Our Quest is in seven parts: (best read with C highlighting turned on)

I) Preparation
	- In which our potential hero is flown quickly over the landscape for a
	  taste of its scope.  Suitable for the armchair coders and other such
	  persons of faint constitution.

II) Guest
	- Where we encounter the first tantalising wisps of code, and come to
	  understand the details of the life of a Guest kernel.

III) Drivers
	- Whereby the Guest finds its voice and become useful, and our
	  understanding of the Guest is completed.

IV) Launcher
	- Where we trace back to the creation of the Guest, and thus begin our
	  understanding of the Host.

V) Host
	- Where we master the Host code, through a long and tortuous journey.
	  Indeed, it is here that our hero is tested in the Bit of Despair.

VI) Switcher
	- Where our understanding of the intertwined nature of Guests and Hosts
	  is completed.

VII) Mastery
	- Where our fully fledged hero grapples with the Great Question:
	  "What next?"

make Preparation!
Rusty Russell.