WSL2-Linux-Kernel/drivers/lguest
Andy Lutomirski 375074cc73 x86: Clean up cr4 manipulation
CR4 manipulation was split, seemingly at random, between direct
(write_cr4) and using a helper (set/clear_in_cr4).  Unfortunately,
the set_in_cr4 and clear_in_cr4 helpers also poke at the boot code,
which only a small subset of users actually wanted.

This patch replaces all cr4 access in functions that don't leave cr4
exactly the way they found it with new helpers cr4_set_bits,
cr4_clear_bits, and cr4_set_bits_and_update_boot.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Vince Weaver <vince@deater.net>
Cc: "hillf.zj" <hillf.zj@alibaba-inc.com>
Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/495a10bdc9e67016b8fd3945700d46cfd5c12c2f.1414190806.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-02-04 12:10:41 +01:00
..
x86 x86: Clean up cr4 manipulation 2015-02-04 12:10:41 +01:00
Kconfig lguest: fix paths in comments 2013-03-07 09:56:46 +11:00
Makefile lguest: move the lguest tool to the tools directory 2012-01-12 15:44:47 +10:30
README lguest: documentation I: Preparation 2007-07-26 11:35:16 -07:00
core.c mm/vmalloc.c: clean up map_vm_area third argument 2014-08-06 18:01:19 -07:00
hypercalls.c lguest: update commentry 2009-07-30 16:03:46 +09:30
interrupts_and_traps.c lguest: fix guest kernel stack overflow when TF bit set. 2013-09-06 08:09:27 +09:30
lg.h lguest: cache last cpu we ran on. 2013-04-22 15:45:03 +09:30
lguest_device.c virtio: allow finalize_features to fail 2014-12-09 16:32:32 +02:00
lguest_user.c lguest: improve code readability in lg_cpu_start. 2013-04-30 09:24:30 +09:30
page_tables.c drivers/lguest/page_tables.c: rename do_set_pte() 2014-04-07 16:35:52 -07:00
segments.c lguest: switch segment-voodoo-numbers to readable symbols 2012-01-12 15:44:47 +10:30

README

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.