sysemu/sysemu.h is a rather unfocused dumping ground for stuff related
to the system-emulator. Evidence:
* It's included widely: in my "build everything" tree, changing
sysemu/sysemu.h still triggers a recompile of some 1100 out of 6600
objects (not counting tests and objects that don't depend on
qemu/osdep.h, down from 5400 due to the previous two commits).
* It pulls in more than a dozen additional headers.
Split stuff related to run state management into its own header
sysemu/runstate.h.
Touching sysemu/sysemu.h now recompiles some 850 objects. qemu/uuid.h
also drops from 1100 to 850, and qapi/qapi-types-run-state.h from 4400
to 4200. Touching new sysemu/runstate.h recompiles some 500 objects.
Since I'm touching MAINTAINERS to add sysemu/runstate.h anyway, also
add qemu/main-loop.h.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20190812052359.30071-30-armbru@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
[Unbreak OS-X build]
In my "build everything" tree, changing sysemu/sysemu.h triggers a
recompile of some 5400 out of 6600 objects (not counting tests and
objects that don't depend on qemu/osdep.h).
Almost a third of its inclusions are actually superfluous. Delete
them. Downgrade two more to qapi/qapi-types-run-state.h, and move one
from char/serial.h to char/serial.c.
hw/semihosting/config.c, monitor/monitor.c, qdev-monitor.c, and
stubs/semihost.c define variables declared in sysemu/sysemu.h without
including it. The compiler is cool with that, but include it anyway.
This doesn't reduce actual use much, as it's still included into
widely included headers. The next commit will tackle that.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20190812052359.30071-27-armbru@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
In my "build everything" tree, changing hw/qdev-properties.h triggers
a recompile of some 2700 out of 6600 objects (not counting tests and
objects that don't depend on qemu/osdep.h).
Many places including hw/qdev-properties.h (directly or via hw/qdev.h)
actually need only hw/qdev-core.h. Include hw/qdev-core.h there
instead.
hw/qdev.h is actually pointless: all it does is include hw/qdev-core.h
and hw/qdev-properties.h, which in turn includes hw/qdev-core.h.
Replace the remaining uses of hw/qdev.h by hw/qdev-properties.h.
While there, delete a few superfluous inclusions of hw/qdev-core.h.
Touching hw/qdev-properties.h now recompiles some 1200 objects.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Daniel P. Berrangé" <berrange@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20190812052359.30071-22-armbru@redhat.com>
In my "build everything" tree, changing qemu/main-loop.h triggers a
recompile of some 5600 out of 6600 objects (not counting tests and
objects that don't depend on qemu/osdep.h). It includes block/aio.h,
which in turn includes qemu/event_notifier.h, qemu/notify.h,
qemu/processor.h, qemu/qsp.h, qemu/queue.h, qemu/thread-posix.h,
qemu/thread.h, qemu/timer.h, and a few more.
Include qemu/main-loop.h only where it's needed. Touching it now
recompiles only some 1700 objects. For block/aio.h and
qemu/event_notifier.h, these numbers drop from 5600 to 2800. For the
others, they shrink only slightly.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20190812052359.30071-21-armbru@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
This patch to fix the origin "char *data" memory leak, code style issue
and add necessary check here.
Reported-by: Coverity (CID 1402785)
Signed-off-by: Zhang Chen <chen.zhang@intel.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Jason Wang <jasowang@redhat.com>
When invoking qemu-bridge-helper in 'net_bridge_run_helper',
instead of using fixed sized buffers, use dynamically allocated
ones initialised and returned by g_strdup_printf().
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Reviewed-by: Li Qiang <liq3ea@gmail.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
This patch make colo-compare can send message to remote COLO frame(Xen) when occur checkpoint.
Signed-off-by: Zhang Chen <chen.zhang@intel.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
We need use this function to send notification message for remote colo-frame(Xen).
So we add new parameter for this job.
Signed-off-by: Zhang Chen <chen.zhang@intel.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Add chardev handler to send notification to remote(current from Xen) colo-frame.
Signed-off-by: Zhang Chen <chen.zhang@intel.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
We add the "notify_dev=chardevID" parameter. After that colo-compare can connect with
remote(currently just for Xen, KVM-COLO didn't need it.) colo-frame through chardev socket,
it can notify remote(Xen) colo-frame to handle checkpoint event.
Signed-off-by: Zhang Chen <chen.zhang@intel.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Previously there was a single instance of the timer used by
monitor triggered announces, that's OK, but when combined with the
previous change that lets you have announces for subsets of interfaces
it's a bit restrictive if you want to do different things to different
interfaces.
Add an 'id' field to the announce, and maintain a list of the
timers based on id.
This allows you to for example:
a) Start an announce going on interface eth0 for a long time
b) Start an announce going on interface eth1 for a long time
c) Kill the announce on eth0 while leaving eth1 going.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Allow the caller to restrict the set of interfaces that announces are
sent on. The default is still to send on all interfaces.
e.g.
{ "execute": "announce-self", "arguments": { "initial": 50, "max": 550, "rounds": 5, "step": 50, "interfaces": ["vn2", "vn1"] } }
This doesn't affect the behaviour of migraiton announcments.
Note: There's still only one timer for the qmp command, so that
performing an 'announce-self' on one list of interfaces followed
by another 'announce-self' on another list will stop the announces
on the existing set.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Since the get_str_sep() function is no longer used in
net/net.c, we can remove it.
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Use the glib function to split host address and port in
the parse_host_port() function.
Suggested-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
net_client_init() uses a variable length array to store the prefix
of 'ipv6-net' parameter (e.g. if ipv6-net=fec0::0/64, the prefix
is 'fec0::0').
This patch introduces g_strsplit() to split the 'ipv6-net' parameter,
so we can remove the variable length array.
Suggested-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
If 'ipv6-prefixlen' is not a number, the current behaviour
produces an assertion failure:
$ qemu-system-x86_64 -net user,ipv6-net=feca::0/a
qemu-system-x86_64: qemu/util/qemu-option.c:1175: qemu_opts_foreach:
Assertion `!errp || !*errp' failed.
Aborted (core dumped)
This patch fixes it, jumping to the end of the function when
'ipv6-prefixlen' is not a number, and printing the more friendly
message:
$ qemu-system-x86_64 -net user,ipv6-net=feca::0/a
qemu-system-x86_64: Parameter 'ipv6-prefixlen' expects a number
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
No header includes qemu-common.h after this commit, as prescribed by
qemu-common.h's file comment.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20190523143508.25387-5-armbru@redhat.com>
[Rebased with conflicts resolved automatically, except for
include/hw/arm/xlnx-zynqmp.h hw/arm/nrf51_soc.c hw/arm/msf2-soc.c
block/qcow2-refcount.c block/qcow2-cluster.c block/qcow2-cache.c
target/arm/cpu.h target/lm32/cpu.h target/m68k/cpu.h target/mips/cpu.h
target/moxie/cpu.h target/nios2/cpu.h target/openrisc/cpu.h
target/riscv/cpu.h target/tilegx/cpu.h target/tricore/cpu.h
target/unicore32/cpu.h target/xtensa/cpu.h; bsd-user/main.c and
net/tap-bsd.c fixed up]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20190523143508.25387-3-armbru@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Buglink: https://launchpad.net/bugs/1823458
Currently, a user CHR_EVENT_CLOSED event will cause net_vhost_user_event()
to call vhost_user_cleanup(), which calls vhost_net_cleanup() for all
its queues. However, vhost_net_cleanup() must never be called like
this for fully-initialized nets; when other code later calls
vhost_net_stop() - such as from virtio_net_vhost_status() - it will try
to access the already-cleaned-up fields and fail with assertion errors
or segfaults.
The vhost_net_cleanup() will eventually be called from
qemu_cleanup_net_client().
Signed-off-by: Dan Streetman <ddstreet@canonical.com>
Message-Id: <20190416184624.15397-3-dan.streetman@canonical.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Because event_unhandled_count may be accessed concurrently, it needs
to be protected by taking the lock. However the assert is outside the
lock, probably causing it to read garbage and aborting Qemu erroneously.
The Bug only happens when running Qemu in COLO mode.
This Patch fixes the following bug: https://bugs.launchpad.net/qemu/+bug/1824622
Signed-off-by: Lukas Straub <lukasstraub2@web.de>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Zhang Chen <chen.zhang@intel.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Reword and add a missing parentheses at the end of the
error message.
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Header guard symbols should match their file name to make guard
collisions less likely.
Cleaned up with scripts/clean-header-guards.pl, followed by some
renaming of new guard symbols picked by the script to better ones.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20190315145123.28030-6-armbru@redhat.com>
[Rebase to master: update include/hw/net/ne2000-isa.h]
We are printing all other help output to stdout already (e.g. "-help",
"-cpu help" and "-machine help" output). So the "-net nic,model=help"
output should go to stdout instead of stderr, too. And while we're at
it, also print the NICs line by line, like we do it e.g. with the
"-cpu help" or "-M help" output, too.
Buglink: https://bugs.launchpad.net/qemu/+bug/1574327
Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20190423160608.7519-1-thuth@redhat.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
The fcntl will change the flags directly, use qemu_set_nonblock()
instead.
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Li Qiang <liq3ea@gmail.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
-net socket has a fd argument, and may be passed pre-opened sockets.
TCP sockets use framing.
UDP sockets have datagram boundaries.
When given a unix dgram socket, it will be able to read from it, but
will attempt to send on the dgram_dst, which is unset. The other end
will not receive the data.
Let's teach -net socket to recognize a UNIX DGRAM socket, and use the
regular send() command (without dgram_dst).
This makes running slirp out-of-process possible that
way (python pseudo-code):
a, b = socket.socketpair(socket.AF_UNIX, socket.SOCK_DGRAM)
subprocess.Popen('qemu -net socket,fd=%d -net user' % a.fileno(), shell=True)
subprocess.Popen('qemu ... -net nic -net socket,fd=%d' % b.fileno(), shell=True)
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
We spell out sub/dir/ in sub/dir/trace-events' comments pointing to
source files. That's because when trace-events got split up, the
comments were moved verbatim.
Delete the sub/dir/ part from these comments. Gets rid of several
misspellings.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20190314180929.27722-3-armbru@redhat.com
Message-Id: <20190314180929.27722-3-armbru@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Take a VhostUserState* that can be pre-allocated, and initialize it
with the associated chardev.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Tiwei Bie <tiwei.bie@intel.com>
Message-Id: <20190308140454.32437-4-marcandre.lureau@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Use the "system" libslirp if its present or requested.
Else build with a static libslirp.a if slirp/ is checked
out ("internal") or a submodule ("git").
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20190212162524.31504-7-marcandre.lureau@redhat.com>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Prepare for making slirp/ a standalone project.
Remove some useless includes while at it.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20190212162524.31504-5-marcandre.lureau@redhat.com>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
slirp migration code uses QEMU vmstate so far, when building WITH_QEMU.
Introduce slirp_state_{load,save,version}() functions to move the
state saving handling to libslirp side.
So far, the bitstream compatibility should remain equal with current
QEMU, as this is effectively using the same code, with the same format
etc. When libslirp is made standalone, we will need some mechanism to
ensure bitstream compatibility regardless of the libslirp version
installed. See the FIXME note in the code.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20190212162524.31504-3-marcandre.lureau@redhat.com>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Add a qmp command that can trigger guest announcements.
It uses its own announce-timer instance, and parameters
passed to it explicitly in the command.
Like most qmp commands, it's in the main thread/bql, so
there's no racing with any outstanding timer.
Based on work of Germano Veit Michel <germano@redhat.com> and
Vladislav Yasevich <vyasevic@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Some network devices have a capability to do self announcements
(ex: virtio-net). Add infrastructure that would allow devices
to expose this ability.
Signed-off-by: Vladislav Yasevich <vyasevic@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Switch the announcements to using the new announce timer.
Move the code that does it to announce.c rather than savevm
because it really has nothing to do with the actual migration.
Migration starts the announce from bh's and so they're all
in the main thread/bql, and so there's never any racing with
the timers themselves.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
The 'announce timer' will be used by migration, and explicit
requests for qemu to perform network announces.
Based on the work by Germano Veit Michel <germano@redhat.com>
and Vlad Yasevich <vyasevic@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Changes:
- Save CPU cycles by computing the return value while scanning the
input iovec, rather than calling iov_size() at the end.
- Remove check for s->tx != NULL, because it cannot happen.
- Cache ring->tail in a local variable and use it to check for
space in the TX ring. The use of nm_ring_empty() was invalid,
because nobody is updating ring->cur and ring->head at that point.
- In case we run out of netmap slots in the middle of a packet,
move the wake-up point by advancing ring->cur, but do not
expose the incomplete packet (i.e., by updating also ring->head).
Signed-off-by: Vincenzo Maffione <v.maffione@gmail.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Improve code reuse by implementing netmap_receive() with a call
to netmap_receive_iov().
Signed-off-by: Vincenzo Maffione <v.maffione@gmail.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
This change improves the handling of incomplete multi-slot packets
(e.g. with the NS_MOREFRAG set), by advancing ring->head only on
complete packets. The ring->cur pointer is advanced in any case in
order to acknowledge the kernel and move the wake-up point (thus
avoiding repeated wake-ups).
Also don't be verbose when incomplete packets are found.
Signed-off-by: Vincenzo Maffione <v.maffione@gmail.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Fix duplicated code:
https://bugs.launchpad.net/qemu/+bug/1811499
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Zhang Chen <chen.zhang@intel.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
vhost-user already has a way to communicate the endianness of the guest
via the vring endianness messages. The vring endianness always matches
the vnet header endianness so there is no need to do anything else in
the backend.
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1543851204-41186-9-git-send-email-pbonzini@redhat.com>
Message-Id: <1550165756-21617-5-git-send-email-pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
hw/net/vhost_net.c needs functions that are declared in net/vhost-user.c: the
vhost-user code is always compiled into QEMU, only the constructor
net_init_vhost_user is unreachable. Also, net/vhost-user.c needs functions
declared in hw/virtio/vhost-stub.c even if no virtio device exists.
Break this dependency. First, add a minimal version of net/vhost-user.c,
with no functionality and no dependency on vhost code. Second, #ifdef out
the calls back to net/vhost-user.c from hw/net/vhost_net.c.
While at it, this patch fixes the CONFIG_VHOST_NET_USE*D* typo.
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <1543851204-41186-3-git-send-email-pbonzini@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1550165756-21617-3-git-send-email-pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This will be needed by vhost-user-test, when each test switches to
its own GMainLoop and GMainContext. Otherwise, for a reconnecting
socket the initial connection will happen on the default GMainContext,
and no one will be listening on it.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20190202110834.24880-1-pbonzini@redhat.com>
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
This is friendlier for FFI bindings.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
It would be legitimate to use libslirp without glib. Let's
add_poll/get_revents pair of callbacks to provide the same
functionality.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Remove hard-coded dependency on slirp in main-loop, and use a "poll"
notifier instead. The notifier is registered per slirp instance.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Use a more descriptive name for the callback.
Reuse the SlirpWriteCb type. Wrap it to check that all data has been written.
Return a ssize_t for potential error handling and data-loss reporting.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Introduce a SlirpCb callback to kick the main io-thread.
Add an intermediary sodrop() function that will call SlirpCb.notify
callback when sbdrop() returns true.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Add a counter-part to register_poll_fd() for completeness.
(so far, register_poll_fd() is called only on struct socket fd)
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Replace qemu_set_nonblock() with slirp_set_nonblock()
qemu_set_nonblock() does some event registration with the main
loop. Add a new callback register_poll_fd() for that reason.
Always build the fd-register stub, to avoid #if WIN32.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Markus Armbruster