linux/drivers/lguest
Rusty Russell f616fe4fee lguest: clear cached last cpu when guest_set_pgd() called.
commit v3.9-rc1-53-g6d0cda9 "lguest: cache last cpu we ran on." missed
one case, which causes a triple fault.  The guest calls guest_set_pgd()
on the top page, and we carefully remap the Switcher text page.  But
we didn't reset last_host_cpu, so map_switcher_in_guest() thinks
the guest's regs and IDT/GDT etc are already mapped.

Reported-by: Paul Bolle <pebolle@tiscali.nl>
Tested-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-05-08 10:49:18 +09:30
..
x86 lguest: assume Switcher text is a single page. 2013-04-22 15:31:36 +09:30
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 lguest: map Switcher below fixmap. 2013-04-22 15:45:03 +09:30
hypercalls.c lguest: update commentry 2009-07-30 16:03:46 +09:30
interrupts_and_traps.c lguest: update comments 2011-07-22 14:39:50 +09:30
lg.h lguest: cache last cpu we ran on. 2013-04-22 15:45:03 +09:30
lguest_device.c virtio: make config_ops const 2013-02-11 15:32:17 +10:30
lguest_user.c lguest: improve code readability in lg_cpu_start. 2013-04-30 09:24:30 +09:30
page_tables.c lguest: clear cached last cpu when guest_set_pgd() called. 2013-05-08 10:49:18 +09:30
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.