Bit 1 in the x86 EFLAGS is always set.  Name the macro something that
actually tries to explain what it is all about, rather than being a
tautology.
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Link: http://lkml.kernel.org/n/tip-f10rx5vjjm6tfnt8o1wseb3v@git.kernel.org

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>

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>

Instead of using unlazy_fpu() check if user_has_fpu() and set/clear
the host TS bits so that the lguest works fine with both the
lazy/non-lazy FPU host models with minimal changes.
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/1345842782-24175-6-git-send-email-suresh.b.siddha@intel.com
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

The x86_64 kernel pushes the fake kernel stack in
arch/x86/kernel/entry_64.S:FAKE_STACK_FRAME, and
rflags register in it does not conform to the specification.

Although Intel's manual[1] says bit 1 of it shall be set to 1,
this bit is cleared to 0 on pushing the fake stack.

[1] Intel(R) 64 and IA-32 Architectures Software Developer's Manual
    Vol.1 3-21 Figure 3-8. EFLAGS Register

If it is not on purpose, it is better to be fixed, because
it can lead some tools misunderstanding the stack frame. For example,
"crash" utility[2] actually detects it and warns you like
below:

       RIP: ffffffff8005dfa2  RSP: ffff8104ce0c7f58  RFLAGS: 00000200
       [...]

       bt: WARNING: possibly bogus exception frame
Signed-off-by: NSeiichi Ikarashi <s.ikarashi@jp.fujitsu.com>
Tested-by: NMasayoshi MIZUMA <m.mizuma@jp.fujitsu.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

We were blatting too much of the register.  Linux didn't care, but in
theory it might.
Reported-by: NJonas Maebe <jonas.maebe@elis.ugent.be>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

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

Now we no longer use vmcall, we don't need to rewrite it in the Guest.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

arch/x86/lguest/boot.c: In function ‘lguest_init_IRQ’:
arch/x86/lguest/boot.c:824: error: macro "__this_cpu_write" requires 2 arguments, but only 1 given
arch/x86/lguest/boot.c:824: error: ‘__this_cpu_write’ undeclared (first use in this function)
arch/x86/lguest/boot.c:824: error: (Each undeclared identifier is reported only once
arch/x86/lguest/boot.c:824: error: for each function it appears in.)

drivers/lguest/x86/core.c: In function ‘copy_in_guest_info’:
drivers/lguest/x86/core.c:94: error: lvalue required as left operand of assignment
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Use this_cpu_ops in a couple of places in lguest.
Signed-off-by: NChristoph Lameter <cl@linux.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

It's only used by cmpxchg8b_emu (see db677ffa for the gory
details), and fixing that to be paravirt aware would be more work than
simply ignoring it (and AFAICT only help lguest).  This makes lguest
work on machines which have cmpxchg8b, for kernels compiled for older
processors.

(We can't emulate it properly: the popf which expects to restore interrupts
does not trap).
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: virtualization@lists.osdl.org

This patch updates misc percpu related symbols such that percpu
symbols are unique and don't clash with local symbols.  This serves
two purposes of decreasing the possibility of global percpu symbol
collision and allowing dropping per_cpu__ prefix from percpu symbols.

* drivers/crypto/padlock-aes.c: s/last_cword/paes_last_cword/

* drivers/lguest/x86/core.c: s/last_cpu/lg_last_cpu/

* drivers/s390/net/netiucv.c: rename the variable used in a macro to
  avoid clashing with percpu symbol

* arch/mn10300/kernel/kprobes.c: replace current_ prefix with cur_ for
  static variables.  Please note that percpu symbol current_kprobe
  can't be changed as it's used by generic code.

Partly based on Rusty Russell's "alloc_percpu: rename percpu vars
which cause name clashes" patch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Reviewed-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Chuck Ebbert <cebbert@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com

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>

When KVM is loaded, and hence VT set up, the vmcall instruction in an
lguest guest causes a #GP, not #UD.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fixes guest crash 'lguest: bad read address 0x4800000 len 256'

The new per-cpu allocator ends up handing a non-linear address to
write_gdt_entry.  We do __pa() on it, and hand it to the host, which
kills us.

I've long wanted to make the hypercall "LOAD_GDT_ENTRY" to match the IDT
code, but had no pressing reason until now.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: lguest@ozlabs.org

Typical message: 'lguest: unhandled trap 6 at 0x418726 (0x0)'

vmlinux guests were broken by 4cd8b5e2
'lguest: use KVM hypercalls', which rewrites guest text from kvm hypercalls
to trap 31.

The Launcher mmaps the kernel image.  The Guest executes and
immediately faults in the first text page (read-only).  Then it hits a
hypercall, and we rewrite that hypercall, causing a copy-on-write.
But the Guest pagetables still refer to the old page: we fault again,
but as Host we see the hypercall already rewritten, and pass the fault
back to the Guest.  The Guest hasn't set up an IDT yet, so we kill it.

This doesn't happen with bzImages: they unpack themselves and so the
text pages are already read-write.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Tested-by: NPatrick McHardy <kaber@trash.net>

Impact: cleanup

This patch allow us to use KVM hypercalls

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

To support my little make-x86-bitops-use-proper-typechecking projectlet.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrea Arcangeli <andrea@qumranet.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

It's not even passed on to smp_call_function() anymore, since that
was removed. So kill it.
Acked-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Reviewed-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

I am able to reproduce the oops reported by Simon in __switch_to() with
lguest.

My debug showed that there is at least one lguest specific
issue (which should be present in 2.6.25 and before aswell) and it got
exposed with a kernel oops with the recent fpu dynamic allocation patches.

In addition to the previous possible scenario (with fpu_counter), in the
presence of lguest, it is possible that the cpu's TS bit it still set and the
lguest launcher task's thread_info has TS_USEDFPU still set.

This is because of the way the lguest launcher handling the guest's TS bit.
(look at lguest_set_ts() in lguest_arch_run_guest()). This can result
in a DNA fault while doing unlazy_fpu() in __switch_to(). This will
end up causing a DNA fault in the context of new process thats
getting context switched in (as opossed to handling DNA fault in the context
of lguest launcher/helper process).

This is wrong in both pre and post 2.6.25 kernels. In the recent
2.6.26-rc series, this is showing up as NULL pointer dereferences or
sleeping function called from atomic context(__switch_to()), as
we free and dynamically allocate the FPU context for the newly
created threads. Older kernels might show some FPU corruption for processes
running inside of lguest.

With the appended patch, my test system is running for more than 50 mins
now. So atleast some of your oops (hopefully all!) should get fixed.
Please give it a try. I will spend more time with this fix tomorrow.
Reported-by: NSimon Holm Thøgersen <odie@cs.aau.dk>
Reported-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

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>

drivers/lguest/x86/core.c: In function ‘copy_in_guest_info’:
drivers/lguest/x86/core.c:97: error: ‘struct x86_hw_tss’ has no member named ‘esp1’
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This changes size-specific register names (eip/rip, esp/rsp, etc.) to
generic names in the thread and tss structures.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

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>

events represented in the 'changed' bitmap are per-cpu, not per-guest.
move it to the lg_cpu structure
Signed-off-by: NGlauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

in our new model, pages are assigned to a virtual cpu, not to a guest.
We move it to the lg_cpu structure.
Signed-off-by: NGlauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

in our model, a guest does not run in a cpu anymore: a virtual cpu
does. So we change last_guest to last_cpu
Signed-off-by: NGlauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

this patch makes the pgdir management per-vcpu. The pgdirs pool
is still guest-wide (although it'll probably need to grow when we
are really executing more vcpus), but the pgdidx index is gone,
since it makes no sense anymore. Instead, we use a per-vcpu
index.
Signed-off-by: NGlauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

lguest struct have room for some fields, namely, cr2, ts, esp1
and ss1, that are not really guest-wide, but rather, vcpu-wide.

This patch puts it in the vcpu struct
Signed-off-by: NGlauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

The fields found in lguest_arch are not really per-guest,
but per-cpu (gdt, idt, etc). So this patch turns lguest_arch
into lg_cpu_arch.

It makes sense to have a per-guest per-arch struct, but this
can be addressed later, when the need arrives.
Signed-off-by: NGlauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

This is the most obvious per-vcpu field: registers.

So this patch moves it from struct lguest to struct vcpu,
and patch the places in which they are used, accordingly
Signed-off-by: NGlauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

emulate_insn() needs to know about current eip, which will be,
in the future, a per-vcpu thing. So in this patch, the function
prototype is modified to receive a vcpu struct
Signed-off-by: NGlauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

The switcher needs to be mapped per-vcpu, because different vcpus
will potentially have different page tables (they don't have to,
because threads will share the same).

So our first step is the make the function receive a vcpu struct
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>

Replace all lock_cpu_hotplug/unlock_cpu_hotplug from the kernel and use
get_online_cpus and put_online_cpus instead as it highlights the
refcount semantics in these operations.

The new API guarantees protection against the cpu-hotplug operation, but
it doesn't guarantee serialized access to any of the local data
structures. Hence the changes needs to be reviewed.

In case of pseries_add_processor/pseries_remove_processor, use
cpu_maps_update_begin()/cpu_maps_update_done() as we're modifying the
cpu_present_map there.
Signed-off-by: NGautham R Shenoy <ego@in.ibm.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

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>

Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>