Currently map_vm_area() takes (struct page *** pages) as third argument,
and after mapping, it moves (*pages) to point to (*pages +
nr_mappped_pages).

It looks like this kind of increment is useless to its caller these
days.  The callers don't care about the increments and actually they're
trying to avoid this by passing another copy to map_vm_area().

The caller can always guarantee all the pages can be mapped into vm_area
as specified in first argument and the caller only cares about whether
map_vm_area() fails or not.

This patch cleans up the pointer movement in map_vm_area() and updates
its callers accordingly.
Signed-off-by: NWANG Chao <chaowang@redhat.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Now we've adjusted all the code, we can simply set switcher_addr to
wherever it needs to go below the fixmaps, rather than asserting that
it should be so.

With large NR_CPUS and PAE, people were hitting the "mapping switcher
would thwack fixmap" message.
Reported-by: NPaul Bolle <pebolle@tiscali.nl>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

We currently use the whole top PGD entry for the switcher, so we
simply share a fixed page of PTEs between all guests (actually, it's
one per Host CPU, to ensure isolation between guests).

Changes to a scheme where every guest has its own mappings.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

We will need this in page_table.c soon.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

ie. SHARED_SWITCHER_PAGES == 1.  It is well under a page, and it's a
minor simplification: it's nice to have *one* simplification in a
patch series!
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

There is a single page with the Switcher in it, but it's followed by 2
pages per Host CPU.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

We currently use the whole top PGD entry for the switcher, but that's
hitting the fixmap in some configurations (mainly, large NR_CPUS).
Introduce a variable, currently set to the constant.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Signed-off-by: NAlex Russell <giles.alex@hotmail.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

run_guest tries to freeze the current process after it has handled
pending interrupts and before it calls lguest_arch_run_guest.
This doesn't work nicely if the task has been killed while being frozen
and when we want to handle that signal as soon as possible.
Let's move try_to_freeze before we check for pending signal so that we
can get out of the loop as soon as possible.
Signed-off-by: NMichal Hocko <mhocko@suse.cz>
Acked-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

We actually can run under KVM, as it doesn't paravirtualize anything we
need to use; reduce the check to checking we are the normal ringlevel.
Reported-by: NStefanos Geraggelos <sgerag@cslab.ece.ntua.gr>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au># HG changeset patch

Also removes a long-unused #define and an extraneous semicolon.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

We can use alloc_page() instead of get_zeroed_page() and virt_to_page()
Signed-off-by: NXiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Every so often, after code shuffles, I need to go through and unbitrot
the Lguest Journey (see drivers/lguest/README).  Since we now use RCU in
a simple form in one place I took the opportunity to expand that explanation.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>

I don't really notice it (except to begrudge the extra vertical
space), but Ingo does.  And he pointed out that one excuse of lguest
is as a teaching tool, it should set a good example.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Ingo Molnar <mingo@redhat.com>

We no longer need an efficient mechanism to force the Guest back into
host userspace, as each device is serviced without bothering the main
Guest process (aka. the Launcher).
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Currently, when a Guest wants to perform I/O it calls LHCALL_NOTIFY with
an address: the main Launcher process returns with this address, and figures
out what device to run.

A far nicer model is to let processes bind an eventfd to an address: if we
find one, we simply signal the eventfd.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Davide Libenzi <davidel@xmailserver.org>

Map switcher with executable page table entries.
(This bug didn't matter before PAE and hence NX support -- RR)
Signed-off-by: NMatias Zabaljauregui <zabaljauregui@gmail.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

lguest never checked for pending interrupts when enabling interrupts, and
things still worked.  However, it makes a significant difference to TCP
performance, so it's time we fixed it by introducing a pending_irq flag
and checking it on irq_restore and irq_enable.

These two routines are now too big to patch into the 8/10 bytes
patch space, so we drop that code.

Note: The high latency on interrupt delivery had a very curious
effect: once everything else was optimized, networking without GSO was
faster than networking with GSO, since more interrupts were sent and
hence a greater chance of one getting through to the Guest!

Note2: (Almost) Closing the same loophole for iret doesn't have any
measurable effect, so I'm leaving that patch for the moment.

Before:
	1GB tcpblast Guest->Host:		30.7 seconds
	1GB tcpblast Guest->Host (no GSO):	76.0 seconds

After:
	1GB tcpblast Guest->Host:		6.8 seconds
	1GB tcpblast Guest->Host (no GSO):	27.8 seconds
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

When the Guest does the LHCALL_HALT hypercall, we go to sleep, expecting
that a timer or the Waker will wake_up_process() us.

But we do it in a stupid way, leaving a classic missing wakeup race.

So split maybe_do_interrupt() into interrupt_pending() and
try_deliver_interrupt(), and check maybe_do_interrupt() and the
"break_out" flag before calling schedule.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Impact: clean up

Rusty told me, some time ago, that he had become a fan of "bool".
So, here are some replacements.

Signed-off-by: Matias Zabaljauregui <zabaljauregui at gmail.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

3 points

lguest_asm.S => i386_head.S
LHCALL_BREAK => LHREQ_BREAK
perferred    => preferred
Signed-off-by: NAtsushi SAKAI <sakaia@jp.fujitsu.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

map_switcher allocates the array, unmap_switcher has to free it
accordingly.
Signed-off-by: NJohannes Weiner <hannes@saeurebad.de>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Took some cycles to re-read the Lguest Journey end-to-end, fix some
rot and tighten some phrases.

Only comments change.  No new jokes, but a couple of recycled old jokes.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Robert Bragg's 5dc33185 tightened
(ie. fixed) the checking in __get_vm_area, and it broke lguest.

lguest should pass the exact "end" it wants, not some random constant
(it was possible previously that it would actually get an address
different from SWITCHER_ADDR).

Also, Fabio Checconi pointed out that we should make sure we're not
hitting the fixmap area.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Robert Bragg <robert@sixbynine.org>

We can save some lines of code by getting rid of
*lg = cpu... lines of code spread everywhere by now.
Signed-off-by: NGlauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

this patch makes the pending_notify field, used to control
pending notifications, per-vcpu, instead of per-guest
Signed-off-by: NGlauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

lguest uses tasks to control its running behaviour (like sending
breaks, controlling halted state, etc). In a per-vcpu environment,
each vcpu will have its own underlying task. So this patch
makes the infrastructure for that possible
Signed-off-by: NGlauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

This patch adapts interrupt processing for using the vcpu struct.
Signed-off-by: NGlauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

this patch changes do_hcall() and do_async_hcall() interfaces (and obviously their
callers) to get a vcpu struct. Again, a vcpu services the hypercall, not the whole
guest
Signed-off-by: NGlauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

This patch makes the run_guest() routine use the lg_cpu struct.
This is required since in a smp guest environment, there's no
more the notion of "running the guest", but rather, it is "running the vcpu"
Signed-off-by: NGlauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Reboot Implemented

(Prevent fd leak, fix style and fix documentation --RR)
Signed-off-by: NBalaji Rao <balajirrao@gmail.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Currently, lguest module can't be compiled without the PARAVIRT flag being
on. This is a fake dependency, since the module itself shouldn't need any
paravirt override. Reason for that is the reference to pv_info structure
in initial loading tests.

This patch removes it in favour of a more generic error message.
Signed-off-by: NGlauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Went through the documentation doing typo and content fixes.  This
patch contains only comment and whitespace changes.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Jes complains that page table code still uses lgread_u32 even though
it now uses general kernel pte types.  The best thing to do is to
generalize lgread_u32 and lgwrite_u32.

This means we lose the efficiency of getuser().  We could potentially
regain it if we used __copy_from_user instead of copy_from_user, but
I'm not certain that our range check is equivalent to access_ok() on
all platforms.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Acked-by: NJes Sorensen <jes@sgi.com>

This patch gets rid of the old lguest host I/O infrastructure and
replaces it with a single hypercall "LHCALL_NOTIFY" which takes an
address.

The main change is the removal of io.c: that mainly did inter-guest
I/O, which virtio doesn't yet support.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

(Based on Ron Minnich's LGUEST_PLAN9_SYSCALL patch).

This patch allows Guests to specify what system call vector they want,
and we try to reserve it.  We only allow one non-Linux system call
vector, to try to avoid DoS on the Host.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Currently we look at the "trapnum" to see if the Guest wants a
hypercall.  But once the hypercall is done we have to reset trapnum to
a bogus value, otherwise if we exit to userspace and return, we'd run
the same hypercall twice (that was a nasty bug to find!).

This has two main effects:

1) When Jes's patch changes the hypercall args to be a generic "struct
   hcall_args" we simply change the type of "lg->hcall".  It's set by
   arch code, so if it has to copy args or something it can do so, and
   point "hcall" into lg->arch somewhere.

2) Async hypercalls only get run when an actual hypercall is pending.
   This simplfies the code a little and is a more logical semantic.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Separate i386 architecture specific from core.c and move it to
x86/core.c and add x86/lguest.h header file to match.
Signed-off-by: NJes Sorensen <jes@sgi.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Back when we had all the Guest state in the switcher, we had a fixed
array of them.  This is no longer necessary.

If we switch the network code to using random_ether_addr (46 bits is
enough to avoid clashes), we can get rid of the concept of "guest id"
altogether.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>