xen_hvm_init() returns -1 without cleaning up on some errors (harmless
long as the caller exit()s on error), dies with hw_error() on others.
hw_error() isn't approprate here.  Clean up to exit() on all errors.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

If the frontend sets out_cons to a value higher than out_prod, it will
cause xenfb_handle_events to loop about 2^32 times. Avoid that by using
better checks at the beginning of the function.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Reported-by: NLing Liu <liuling-it@360.cn>

Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <1450452927-8346-25-git-send-email-armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Suggested-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Acked-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-Id: <1450452927-8346-24-git-send-email-armbru@redhat.com>

Let's follow established naming practice here as well.

Cc: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: NMarkus Armbruster <armbru@pond.sub.org>
Acked-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-Id: <1450452927-8346-23-git-send-email-armbru@redhat.com>

The arguments of error_report() should yield a short error string
without newlines.

A few places try to print additional help after the error message by
embedding newlines in the error string.  That's nice, but let's do it
the right way.  Commit 474c2134 cleaned up some, but they keep coming
back.  Offenders tracked down with the Coccinelle semantic patch from
commit 312fd5f2.

Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Pavel Fedin <p.fedin@samsung.com>
Signed-off-by: NMarkus Armbruster <armbru@pond.sub.org>
Reviewed-by: NLaszlo Ersek <lersek@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

The arguments of error_setg() & friends should yield a short error
string without newlines.

Two places try to append additional help to the error message by
embedding newlines in the error string.  That's nice, but let's do it
the right way, with error_append_hint().

Cc: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-Id: <1450452927-8346-20-git-send-email-armbru@redhat.com>
Reviewed-by: NLaszlo Ersek <lersek@redhat.com>

Commit 6daf194d, be62a2eb and 312fd5f2 got rid of a bunch, but they
keep coming back.  Tracked down with the Coccinelle semantic patch
from commit 312fd5f2.

Cc: Fam Zheng <famz@redhat.com>
Cc: Peter Crosthwaite <crosthwaitepeter@gmail.com>
Cc: Bharata B Rao <bharata@linux.vnet.ibm.com>
Cc: Dominik Dingel <dingel@linux.vnet.ibm.com>
Cc: David Hildenbrand <dahi@linux.vnet.ibm.com>
Cc: Jason J. Herne <jjherne@linux.vnet.ibm.com>
Cc: Stefan Berger <stefanb@linux.vnet.ibm.com>
Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
Cc: Changchun Ouyang <changchun.ouyang@intel.com>
Cc: zhanghailiang <zhang.zhanghailiang@huawei.com>
Cc: Pavel Fedin <p.fedin@samsung.com>
Signed-off-by: NMarkus Armbruster <armbru@pond.sub.org>
Reviewed-by: NDr. David Alan Gilbert <dgilbert@redhat.com>
Acked-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Acked-by: NBharata B Rao <bharata@linux.vnet.ibm.com>
Acked-by: NFam Zheng <famz@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-Id: <1450452927-8346-17-git-send-email-armbru@redhat.com>

Not caught by Coccinelle, because we report the error only
conditionally here.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-Id: <1450452927-8346-14-git-send-email-armbru@redhat.com>

Done with this Coccinelle semantic patch

    @@
    expression FMT, E1, E2;
    expression list ARGS;
    @@
    -    error_setg(E1, FMT, ARGS, error_get_pretty(E2));
    +    error_propagate(E1, E2);/*###*/
    +    error_prepend(E1, FMT/*@@@*/, ARGS);

followed by manual cleanup, first because I can't figure out how to
make Coccinelle transform strings, and second to get rid of now
superfluous error_propagate().

We now use or propagate the original error whole instead of just its
message obtained with error_get_pretty().  This avoids suppressing its
hint (see commit 50b7b000), but I can't see how the errors touched in
this commit could come with hints.  It also improves the message
printed with &error_abort when we screw up (see commit 1e9b65bb).
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Done with this Coccinelle semantic patch

    @@
    expression FMT, E, S;
    expression list ARGS;
    @@
    -    error_report(FMT, ARGS, error_get_pretty(E));
    +    error_reportf_err(E, FMT/*@@@*/, ARGS);
    (
    -    error_free(E);
    |
	 exit(S);
    |
	 abort();
    )

followed by a replace of '%s"/*@@@*/' by '"' and some line rewrapping,
because I can't figure out how to make Coccinelle transform strings.

We now use the error whole instead of just its message obtained with
error_get_pretty().  This avoids suppressing its hint (see commit
50b7b000), but I can't see how the errors touched in this commit could
come with hints.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <1450452927-8346-12-git-send-email-armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Prepend the additional information, colon, space to the original
message without enclosing it in parenthesis or quotes, like we do
elsewhere.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-Id: <1450452927-8346-11-git-send-email-armbru@redhat.com>

Both error_report_err() and monitor_printf() print to the same
destination when monitor_printf() is used correctly, i.e. within an
HMP monitor.  Elsewhere, monitor_printf() does nothing, while
error_report_err() reports to stderr.

Most changed functions are HMP command handlers.  These should only
run within an HMP monitor.  The one exception is bdrv_password_cb(),
which should also only run within an HMP monitor.

Four command handlers prefix the error message with the command name:
balloon, migrate_set_capability, migrate_set_parameter, migrate.
Pointless, drop.

Unlike monitor_printf(), error_report_err() uses the error whole
instead of just its message obtained with error_get_pretty().  This
avoids suppressing its hint (see commit 50b7b000).  Example:

    (qemu) device_add ivshmem,id=666
    Parameter 'id' expects an identifier
    Identifiers consist of letters, digits, '-', '.', '_', starting with a letter.
    Try "help device_add" for more information

The "Identifiers consist of..." line is new with this patch.

Coccinelle semantic patch:

    @@
    expression M, E;
    @@
    -    monitor_printf(M, "%s\n", error_get_pretty(E));
    -    error_free(E);
    +    error_report_err(E);
    @r1@
    expression M, E;
    format F;
    position p;
    @@
    -    monitor_printf(M, "...%@F@\n", error_get_pretty(E));@p
    -    error_free(E);
    +    error_report_err(E);
    @script:python@
	p << r1.p;
    @@
    print "%s:%s:%s: prefix dropped" % (p[0].file, p[0].line, p[0].column)
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-Id: <1450452927-8346-4-git-send-email-armbru@redhat.com>

Same Coccinelle semantic patch as in commit 565f65d2.

We now use the original error whole instead of just its message
obtained with error_get_pretty().  This avoids suppressing its hint
(see commit 50b7b000), but I don't think the errors touched in this
commit can come with hints.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-Id: <1450452927-8346-3-git-send-email-armbru@redhat.com>

isa_bus_irqs(), isa_create() and isa_try_create() call hw_error() when
passed a null bus.  Use of hw_error() has always been questionable,
because these are used only during machine initialization, and
printing CPU registers isn't useful there.

Since the previous commit, passing a null bus is a programming error.
Drop the hw_error() and simply let it crash.

Cc: Richard Henderson <rth@twiddle.net>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: "Hervé Poussineau" <hpoussin@reactos.org>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: NMarkus Armbruster <armbru@pond.sub.org>
Reviewed-by: NHervé Poussineau <hpoussin@reactos.org>
Message-Id: <1450354795-31608-12-git-send-email-armbru@redhat.com>
Reviewed-by: NRichard Henderson <rth@twiddle.net>

We can have at most one ISA bus.  If you try to create another one,
isa_bus_new() complains to stderr and returns null.

isa_bus_new() is called in two contexts, machine's init() and device's
realize() methods.  Since complaining to stderr is not proper in the
latter context, convert isa_bus_new() to Error.

Machine's init():

* mips_jazz_init(), called from the init() methods of machines
  "magnum" and "pica"

* mips_r4k_init(), the init() method of machine "mips"

* pc_init1() called from the init() methods of non-q35 PC machines

* typhoon_init(), called from clipper_init(), the init() method of
  machine "clipper"

These callers always create the first ISA bus, hence isa_bus_new()
can't fail.  Simply pass &error_abort.

Device's realize():

* i82378_realize(), of PCI device "i82378"

* ich9_lpc_realize(), of PCI device "ICH9-LPC"

* pci_ebus_realize(), of PCI device "ebus"

* piix3_realize(), of PCI device "pci-piix3", abstract parent of
  "PIIX3" and "PIIX3-xen"

* piix4_realize(), of PCI device "PIIX4"

* vt82c686b_realize(), of PCI device "VT82C686B"

Propagate the error.  Note that these devices are typically created
only by machine init() methods with qdev_init_nofail() or similar.  If
we screwed up and created an ISA bus before that call, we now give up
right away.  Before, we'd hobble on, and typically die in
isa_bus_irqs().  Similar if someone finds a way to hot-plug one of
these critters.

Cc: Richard Henderson <rth@twiddle.net>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: "Hervé Poussineau" <hpoussin@reactos.org>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: NMarkus Armbruster <armbru@pond.sub.org>
Reviewed-by: NMarcel Apfelbaum <marcel@redhat.com>
Reviewed-by: NHervé Poussineau <hpoussin@reactos.org>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Message-Id: <1450370121-5768-11-git-send-email-armbru@redhat.com>

These are "ICH9-LPC" and "ebus".

Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: NMarkus Armbruster <armbru@pond.sub.org>
Reviewed-by: NMarcel Apfelbaum <marcel@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Message-Id: <1450370121-5768-10-git-send-email-armbru@redhat.com>

platform_bus_map_irq() and platform_bus_map_mmio() use hw_error() to
fail.  They run in machine_init_done_notifiers, via
platform_bus_init_notify() and link_sysbus_device().  Printing CPU
registers is not helpful there.

Replace hw_error() by error_report(); exit(1).  If these are
programming errors, it should be replaced by an assertion instead.

While there, observe that both functions always return 0, and
link_sysbus_device() ignores the return value.  Change them to void.

Cc: Alexander Graf <agraf@suse.de>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NThomas Huth <thuth@redhat.com>
Message-Id: <1450370121-5768-9-git-send-email-armbru@redhat.com>

virt_set_gic_version() calls exit(1) when passed an invalid property
value.  Property setters are not supposed to do that.  Screwed up in
commit b92ad394.  Harmless, because the property belongs to a machine.
Set an error object instead.

Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: qemu-arm@nongnu.org
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>

Device realize() methods aren't supposed to call hw_error(), they
should set an error and fail cleanly.  Blindly doing that would be
easy enough, but then realize() would fail without undoing its side
effects.  Just mark it FIXME for now.

Cc: "Andreas Färber" <andreas.faerber@web.de>
Cc: qemu-ppc@nongnu.org
Signed-off-by: NMarkus Armbruster <armbru@pond.sub.org>
Reviewed-by: NThomas Huth <thuth@redhat.com>
Message-Id: <1450370121-5768-6-git-send-email-armbru@redhat.com>

Device init() methods aren't supposed to call hw_error(), they should
report the error and fail cleanly.  Do that.

Cc: "Edgar E. Iglesias" <edgar.iglesias@gmail.com>
Signed-off-by: NMarkus Armbruster <armbru@pond.sub.org>
Reviewed-by: NEdgar E. Iglesias <edgar.iglesias@xilinx.com>
Message-Id: <1450370121-5768-5-git-send-email-armbru@redhat.com>

Device realize() methods aren't supposed to call hw_error(), they
should set an error and fail cleanly.  Do that.

Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: qemu-arm@nongnu.org
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Message-Id: <1450370121-5768-4-git-send-email-armbru@redhat.com>

Device init() methods aren't supposed to call hw_error(), they should
report the error and fail cleanly.  Do that.

The errors are all device misconfiguration.  All callers use
qdev_init_nofail(), so this patch merely converts hw_error() crashes
into &error_abort crashes.  Improvement, because now it crashes closer
to where the misconfiguration bug would be, and a few more bad
examples of hw_error() use are gone.

Cc: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: NMarkus Armbruster <armbru@pond.sub.org>
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Message-Id: <1450370121-5768-3-git-send-email-armbru@redhat.com>

Printing CPU registers is not helpful during machine initialization.
Moreover, these are straightforward configuration or "can get
resources" errors, so dumping core isn't appropriate either.  Replace
hw_error() by error_report(); exit(1).  Matches how we report these
errors in other machine initializations.

Cc: Richard Henderson <rth@twiddle.net>
Cc: qemu-arm@nongnu.org
Cc: qemu-ppc@nongnu.org
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Signed-off-by: NMarkus Armbruster <armbru@pond.sub.org>
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: NThomas Huth <thuth@redhat.com>
Message-Id: <1450370121-5768-2-git-send-email-armbru@redhat.com>
Reviewed-by: NRichard Henderson <rth@twiddle.net>

Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <1449764955-10741-3-git-send-email-armbru@redhat.com>
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>

Done with this Coccinelle semantic patch:

    @@
    type T;
    identifier FUN, RET;
    expression list ARGS;
    expression ERR, EC;
    @@
    (
    -    T RET = FUN(ARGS, &ERR);
    +    T RET = FUN(ARGS, &error_fatal);
    |
    -    RET = FUN(ARGS, &ERR);
    +    RET = FUN(ARGS, &error_fatal);
    |
    -    FUN(ARGS, &ERR);
    +    FUN(ARGS, &error_fatal);
    )
    -    if (ERR != NULL) {
    -        error_report_err(ERR);
    -        exit(EC);
    -    }

This is actually a more elegant version of my initial semantic patch
by courtesy of Eduardo.

It leaves dead Error * variables behind, cleaned up manually.

Cc: qemu-arm@nongnu.org
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEduardo Habkost <ehabkost@redhat.com>

At present, list_pci() shows all PCI devices as being in configured
state. As devices can be deconfigured by the guest, we need to show
the real configuration status instead.
Signed-off-by: NYi Min Zhao <zyimin@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

The commit 8dfbaa6a ("virtio-ccw: introduce ccw specific queue limit")
did not touch the sanity check for the vector argument of the method
virtio_ccw_notify, despite intended as seen from
https://lists.nongnu.org/archive/html/qemu-devel/2015-04/msg02705.html
To be able to scale number of virtqueues using the constant this sanity
check needs to be altered.

Fixes: 8dfbaa6a ("virtio-ccw: introduce ccw specific queue limit")
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NHalil Pasic <pasic@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

In 240240d5 'pc: Add pc-*-2.6 machine classes' HW_COMPAT_2_5 and
PC_COMPAT_2_5 were introduced.

Accordingly, introduce CCW_COMPAT_2_5 that uses HW_COMPAT_2_5.
Signed-off-by: NShmulik Ladkani <shmulik.ladkani@ravellosystems.com>
Message-Id: <1450899731-19517-1-git-send-email-shmulik.ladkani@ravellosystems.com>
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

Switching to the generally used interface changes the output of

s390x-softmmu/qemu-system-s390x -net nic,model=?

from

S390 only supports VirtIO nics

to the rather more useful

qemu: Supported NIC models: virtio

while still giving us a sensible error message for unsupported
models:

s390x-softmmu/qemu-system-s390x -net nic,model=foo
qemu-system-s390x: Unsupported NIC model: foo
Acked-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

Make use of the new FH_ENABLED define in existing code.
Signed-off-by: NYi Min Zhao <zyimin@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

According to the s390 architecture, any mpcifc, pcilg, pcistg,
pcistb and rpcit instructions issued to disabled PCI functions
are rejected, and the instruction completes by setting condition
code 3. In addition, any DMA and MSIX interruption operations
are ignored.
Signed-off-by: NYi Min Zhao <zyimin@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

The s390-virtio machine has been removed; remove the associated devices
as well.

hw/s390x/s390-virtio-bus.c and hw/s390x/s390-virtio-bus.h
have been deleted and removed from hw/s390x/Makefile.objs

virtio-size has no more meaning for the modern machine
and has been removed from helper.c and cpu.h

virtio-serial-s390 belonging to the old machine is
being removed from vl.c
Signed-off-by: NPierre Morel <pmorel@linux.vnet.ibm.com>
Acked-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

Remove machine code for the s390-virtio machine, but keep functions
useful for the ccw machine.
Signed-off-by: NPierre Morel <pmorel@linux.vnet.ibm.com>
Acked-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

New qemu version, new machine.
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

Signed-off-by: NCao jin <caoj.fnst@cn.fujitsu.com>
Message-Id: <1452068575-21543-1-git-send-email-caoj.fnst@cn.fujitsu.com>
Reviewed-by: NAmit Shah <amit.shah@redhat.com>
Signed-off-by: NAmit Shah <amit.shah@redhat.com>

V9fsState now only contains generic fields. Introduce V9fsVirtioState
for virtio transport.  Change virtio-pci and virtio-ccw to use
V9fsVirtioState.
Signed-off-by: NWei Liu <wei.liu2@citrix.com>
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

When processing NCQ commands, AHCI device emulation prepares a
NCQ transfer object; To which an aio control block(aiocb) object
is assigned in 'execute_ncq_command'. In case, when the NCQ
command is invalid, the 'aiocb' object is not assigned, and NCQ
transfer object is left as 'used'. This leads to a use after
free kind of error in 'bdrv_aio_cancel_async' via 'ahci_reset_port'.
Reset NCQ transfer object to 'unused' to avoid it.

[Maintainer edit: s/ACHI/AHCI/ in the commit message. --js]
Reported-by: NQinghao Tang <luodalongde@gmail.com>
Signed-off-by: NPrasad J Pandit <pjp@fedoraproject.org>
Reviewed-by: NJohn Snow <jsnow@redhat.com>
Message-id: 1452282511-4116-1-git-send-email-ppandit@redhat.com
Signed-off-by: NJohn Snow <jsnow@redhat.com>

As the IDEState lba field is an int32_t, make sure we cast to int64_t before
shifting to calculate the offset. Otherwise we end up with an overflow when
trying to access sectors beyond 2GB as can occur when using DVD images.

[Maintainer edit: fixed extraneous parentheses. --js]
Signed-off-by: NMark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: NJohn Snow <jsnow@redhat.com>
Message-id: 1451928613-29476-1-git-send-email-mark.cave-ayland@ilande.co.uk
Signed-off-by: NJohn Snow <jsnow@redhat.com>

Support the legacy -nic syntax for creating PCI network devices
as well as the new-style -device options. This makes life easier
for people moving from x86 KVM virtualization to ARM KVM virtualization
and expecting their network configuration options to work the same
way for both setups.

We use "virtio" as the default NIC model if the user doesn't specify one.
Signed-off-by: NAshok Kumar <ashoks@broadcom.com>
Message-id: 1452091659-17698-1-git-send-email-ashoks@broadcom.com
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
[PMM: expanded and clarified commit message]
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>