Commit graph

208 commits

Author SHA1 Message Date
Paolo Bonzini 0ceb849bd3 AioContext: speed up aio_notify
In many cases, the call to event_notifier_set in aio_notify is unnecessary.
In particular, if we are executing aio_dispatch, or if aio_poll is not
blocking, we know that we will soon get to the next loop iteration (if
necessary); the thread that hosts the AioContext's event loop does not
need any nudging.

The patch includes a Promela formal model that shows that this really
works and does not need any further complication such as generation
counts.  It needs a memory barrier though.

The generation counts are not needed because any change to
ctx->dispatching after the memory barrier is okay for aio_notify.
If it changes from zero to one, it is the right thing to skip
event_notifier_set.  If it changes from one to zero, the
event_notifier_set is unnecessary but harmless.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-07-09 15:50:11 +02:00
Benoît Canet 4e855baabf qapi: Change back sector-count to sectors-count in quorum QAPI events.
fe069d9d had aligned code and documentation while dropping the s from the
actual JSON output. Fix that.

This also fix test/qemu-iotest/081 since the missing s was causing a permutation.

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-07-01 10:15:34 +02:00
Michael S. Tsirkin a628fc8dae vhost-user: typo fixups
Fix typo in field name.
Strip two consequitive empty lines.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2014-06-29 19:39:41 +03:00
Damjan Marion 3fd74b8407 vhost-user: fix regions provied with VHOST_USER_SET_MEM_TABLE message
Old code was affected by memory gaps which resulted in buffer pointers
pointing to address outside of the mapped regions.

Here we are introducing following changes:
 - new function qemu_get_ram_block_host_ptr() returns host pointer
   to the ram block, it is needed to calculate offset of specific
   region in the host memory
 - new field mmap_offset is added to the VhostUserMemoryRegion. It
   contains offset where specific region starts in the mapped memory.
   As there is stil no wider adoption of vhost-user agreement was made
   that we will not bump version number due to this change
 - other fileds in VhostUserMemoryRegion struct are not changed, as
   they are all needed for usermode app implementation
 - region data is not taken from ram_list.blocks anymore, instead we
   use region data which is alredy calculated for use in vhost-net
 - Now multiple regions can have same FD and user applicaton can call
   mmap() multiple times with the same FD but with different offset
   (user needs to take care for offset page alignment)

Signed-off-by: Damjan Marion <damarion@cisco.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Damjan Marion <damarion@cisco.com>
2014-06-29 19:39:40 +03:00
Damjan Marion 46e797c4d3 vhost-user: fix wrong ids in documentation
Signed-off-by: Damjan Marion <damarion@cisco.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2014-06-29 18:59:41 +03:00
Markus Armbruster a22d8e47f7 docs/qmp: Fix documentation of BLOCK_JOB_READY to match code
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-06-27 13:40:41 -04:00
Luiz Capitulino dfab489214 qmp: add qmp-events.txt back
The conversion of events to the QAPI, resulted in the removal of the
docs/qmp/qmp-events.txt file. This was done to avoid having duplicated
information between qmp-events.txt and qapi-event.json.

However, qmp-events.txt contains examples and we're still not sure
how to proper install QAPI docs in the host. To avoid harming users,
it's better to re-add qmp-events.txt for now and deal with the
duplication later.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2014-06-27 09:27:56 -04:00
Wenchao Xia d6f9c82c62 qapi script: clean up in scripts
This patch improve docs and uses c_type(argentry, is_param=True)
in script.

Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-06-27 09:27:56 -04:00
Wenchao Xia fe069d9d59 qapi event: convert QUORUM events
Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-06-23 11:12:28 -04:00
Wenchao Xia 3a44969037 qapi event: convert GUEST_PANICKED
'monitor.h' is still included in target-s390x/kvm.c, since I have
no good way to verify whether other code need it on my x86 host.

Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-06-23 11:12:28 -04:00
Wenchao Xia aef9d3115f qapi event: convert BALLOON_CHANGE
Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-06-23 11:12:28 -04:00
Igor Mammedov 5f41fbba90 qmp: convert ACPI_DEVICE_OST event
... using new QAPI event infrastructure

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-06-23 11:12:28 -04:00
Wenchao Xia 7cfadb6b52 qapi event: convert SPICE events
SPICE_INITIALIZED, SPICE_CONNECTED, SPICE_DISCONNECTED and
SPICE_MIGRATE_COMPLETED are converted in one patch, since they
use some common functions. inet_strfamily() is removed since no
callers exist anymore.

Note that there is no existing doc for SPICE_MIGRATE_COMPLETED
in docs/qmp/qmp-events.txt before this patch.

Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-06-23 11:12:28 -04:00
Wenchao Xia fb6ba0d525 qapi event: convert VNC events
Since VNC_CONNECTED, VNC_DISCONNECTED, VNC_INITIALIZED share some
common functions, convert them in one patch.

Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-06-23 11:12:28 -04:00
Wenchao Xia 0615027903 qapi event: convert NIC_RX_FILTER_CHANGED
Param name is declared as optional, since in code it is an optional
one.

Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-06-23 11:12:28 -04:00
Wenchao Xia bcada37b19 qapi event: convert other BLOCK_JOB events
Since BLOCK_JOB_COMPLETED, BLOCK_JOB_CANCELLED, BLOCK_JOB_READY are
related, convert them in one patch. The block_job_event_* functions
are used to keep encapsulation of BlockJob structure.

Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-06-23 11:12:28 -04:00
Wenchao Xia c120f0fa14 qapi event: convert BLOCK_IMAGE_CORRUPTED
Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-06-23 11:12:27 -04:00
Wenchao Xia 5a2d2cbd88 qapi event: convert BLOCK_IO_ERROR and BLOCK_JOB_ERROR
Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-06-23 11:12:27 -04:00
Wenchao Xia a5ee7bd454 qapi event: convert DEVICE_TRAY_MOVED
Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-06-23 11:12:27 -04:00
Wenchao Xia 24b699fb2b qapi event: convert DEVICE_DELETED
Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-06-23 11:12:27 -04:00
Wenchao Xia 99eaf09c73 qapi event: convert WATCHDOG
Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-06-23 11:12:27 -04:00
Wenchao Xia e010ad8f1e qapi event: convert RTC_CHANGE
This patch also eliminates build time warning caused by no caller
of monitor_qapi_event_throttle().

Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-06-23 11:12:27 -04:00
Wenchao Xia 7a906f7ffb qapi event: convert WAKEUP
Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-06-23 11:12:27 -04:00
Wenchao Xia 2ea4100f44 qapi event: convert SUSPEND_DISK
Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-06-23 11:12:27 -04:00
Wenchao Xia 1d11a95a3e qapi event: convert SUSPEND
Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-06-23 11:12:27 -04:00
Wenchao Xia 591c48fbc5 qapi event: convert RESUME
Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-06-23 11:12:24 -04:00
Wenchao Xia a4e15de9a2 qapi event: convert STOP
Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-06-23 11:01:25 -04:00
Wenchao Xia a6330785f0 qapi event: convert RESET
Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-06-23 11:01:25 -04:00
Wenchao Xia 8432183137 qapi event: convert SHUTDOWN
This patch also eliminates build time warning caused by
QAPI_EVENT_MAX = 0.

Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-06-23 11:01:25 -04:00
Wenchao Xia 21cd70dfc1 qapi script: add event support
qapi-event.py will parse the schema and generate qapi-event.c, then
the API in qapi-event.c can be used to handle events in qemu code.
All API have prefix "qapi_event".

The script mainly includes two parts: generate API for each event
define, generate an enum type for all defined events.

Since in some cases the real emit behavior may change, for example,
qemu-img would not send a event, a callback layer is used to
control the behavior. As a result, the stubs at compile time
can be saved, the binding of block layer code and monitor code
will become looser.

Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-06-23 11:01:25 -04:00
Paolo Bonzini 2bd3bce8ef block: asynchronously stop the VM on I/O errors
With virtio-blk dataplane, I/O errors might occur while QEMU is
not in the main I/O thread.  However, it's invalid to call vm_stop
when we're neither in a VCPU thread nor in the main I/O thread,
even if we were to take the iothread mutex around it.

To avoid this problem, we can raise a request to the main I/O thread,
similar to what QEMU does when vm_stop is called from a CPU thread.
We know that bdrv_error_action is called from an AIO callback, and
the moment at which the callback will fire is not well-defined; it
depends on the moment at which the disk or OS finishes the operation,
which can happen at any time.  Note that QEMU is certainly not in a CPU
thread and we do not need to call cpu_stop_current() like vm_stop() does.

However, we need to ensure that any action taken by management will
result in correct detection of the error _and_ a running VM.  In particular:

- the event must be raised after the iostatus has been set, so that
"info block" will return an iostatus that matches the event.

- the VM must be stopped after the iostatus has been set, so that
"info block" will return an iostatus that matches the runstate.

The ordering between the STOP and BLOCK_IO_ERROR events is preserved;
BLOCK_IO_ERROR is documented to come first.

This makes bdrv_error_action() thread safe (assuming QMP events are,
which is attacked by a separate series).

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-06-23 16:36:13 +08:00
Igor Mammedov 02edd407f3 qmp: add ACPI_DEVICE_OST event handling
emits event when ACPI OSPM evaluates _OST method
of ACPI device.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2014-06-19 18:44:22 +03:00
Nikolay Nikolaev 5fc0e00291 Add vhost-user protocol documentation
This document describes the basic message format used by vhost-user
for communication over a unix domain socket. The protocol is based
on the existing ioctl interface used for the kernel version of vhost.

Signed-off-by: Antonios Motakis <a.motakis@virtualopensystems.com>
Signed-off-by: Nikolay Nikolaev <n.nikolaev@virtualopensystems.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2014-06-19 18:44:18 +03:00
Igor Mammedov 3ef77acab2 acpi: memory hotplug ACPI hardware implementation
- implements QEMU hardware part of memory hotplug protocol
  described at "docs/specs/acpi_mem_hotplug.txt"
- handles only memory add notification event for now

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2014-06-19 16:41:49 +03:00
Paolo Bonzini 471f7e30a4 libcacard: improve documentation
Using the file-backed smartcard backend is black magic, but it can
be useful if your only smartcard bricks itself if it is accessed
the wrong way too many times.

Complete the documentation to include the art of creating certificates
and using them with QEMU, based on Ray Strode's useful tutorial at
https://blogs.gnome.org/halfline/2013/09/08/another-smartcard-post/
but with ccid-card-emulated or vscclient instead of SPICE.

Cc: Ray Strode <rstrode@redhat.com>
Reviewed-by: Alon Levy <alevy@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-06-10 07:44:01 +02:00
Lluís Vilanova 5b808275f3 trace: Multi-backend tracing
Adds support to compile QEMU with multiple tracing backends at the same time.

For example, you can compile QEMU with:

  $ ./configure --enable-trace-backends=ftrace,dtrace

Where 'ftrace' can be handy for having an in-flight record of events, and 'dtrace' can be later used to extract more information from the system.

This patch allows having both available without recompiling QEMU.

Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-06-09 15:43:40 +02:00
Peter Maydell 26edf8cc08 pc,pci,virtio,qdev fixes, tests
new tests for SMBIOS
 SMBIOS fixes
 pc, pci fixes
 qdev patches stayed on list for a month with no review,
 as I told people on KVM forum I'm merging stuch patches
 if they look fine.
 
 Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Merge remote-tracking branch 'remotes/mst/tags/for_upstream' into staging

pc,pci,virtio,qdev fixes, tests

new tests for SMBIOS
SMBIOS fixes
pc, pci fixes
qdev patches stayed on list for a month with no review,
as I told people on KVM forum I'm merging stuch patches
if they look fine.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

* remotes/mst/tags/for_upstream:
  qdev: Add test of qdev_prop_check_global
  qdev: Display warning about unused -global
  tests: add smbios testing
  tests: rename acpi-test to bios-tables-test
  virtio-balloon: return empty data when no stats are available
  pcie_host: Turn pcie_host_init() into an instance_init
  SMBIOS: Fix type 17 field sizes
  SMBIOS: Update Type 0 struct generator for machines >= 2.1
  SMBIOS: Fix endian-ness when populating multi-byte fields
  serial-pci: Set prog interface field of pci config to 16550 compatible

Conflicts:
	include/hw/i386/pc.h
[PMM: fixed trivial conflict in pc.h]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2014-06-05 21:52:37 +01:00
Gerd Hoffmann 2082bac151 docs/multiseat.txt: add note about spice
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2014-06-04 08:40:42 +02:00
Gerd Hoffmann 90525fe279 docs/multiseat.txt: gtk joined the party
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2014-06-04 08:40:42 +02:00
Gerd Hoffmann 3503206a90 docs/multiseat.txt: use autoseat
When using the autoseat feature of systemd/logind we'll only need
a single udev rule for the pci bridge, which simplifies the guest
setup a bit.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2014-06-04 08:40:42 +02:00
Maria Kustova 6815bce542 docs: Define refcount_bits value
The 'refcount_bits' term used in the description of refcount block entry is
not defined in the specification. The definition is added in the
'refcount_order' section where refcount_bits was used as 'width in bits'.

Signed-off-by: Maria Kustova <maria.k@catit.be>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-05-28 14:28:46 +02:00
Gerd Hoffmann 8977bd111f docs: add multiseat.txt
Howto on setting up multiseat for guests.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2014-05-26 08:42:43 +02:00
Ján Tomko 38dbd48b24 virtio-balloon: return empty data when no stats are available
If the guest hasn't updated the stats yet, instead of returning
an error, return '-1' for the stats and '0' as 'last-update'.

This lets applications ignore this without parsing the error message.

Related libvirt patch and discussion:
https://www.redhat.com/archives/libvir-list/2014-May/msg00460.html

Tested against current upstream libvirt - stat reporting works and
it no longer logs errors when the stats are queried on domain startup.
(Note: libvirt doesn't use the last-update field for anything yet)

Signed-off-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2014-05-25 12:46:58 +03:00
Benoît Canet 24fd848950 qapi: skip redundant includes
The purpose of this change is to help create a json file containing
common definitions; each bit of generated C code must be emitted
only one time.

A second history global to all QAPISchema instances has been added
to detect when a file is included more than one time and skip these
includes.
It does not act as a stack and the changes made to it by the
__init__ function are propagated back to the caller so it's really
a global state.

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-05-16 10:35:59 -04:00
Markus Armbruster 87a560c455 qapi: Show qapi-commands.py invocation in qapi-code-gen.txt
While there, pare down the shell prompts.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-05-15 15:16:01 -04:00
Markus Armbruster 297a3646c2 qapi: Replace uncommon use of the error API by the common one
We commonly use the error API like this:

    err = NULL;
    foo(..., &err);
    if (err) {
        goto out;
    }
    bar(..., &err);

Every error source is checked separately.  The second function is only
called when the first one succeeds.  Both functions are free to pass
their argument to error_set().  Because error_set() asserts no error
has been set, this effectively means they must not be called with an
error set.

The qapi-generated code uses the error API differently:

    // *errp was initialized to NULL somewhere up the call chain
    frob(..., errp);
    gnat(..., errp);

Errors accumulate in *errp: first error wins, subsequent errors get
dropped.  To make this work, the second function does nothing when
called with an error set.  Requires non-null errp, or else the second
function can't see the first one fail.

This usage has also bled into visitor tests, and two device model
object property getters rtc_get_date() and balloon_stats_get_all().

With the "accumulate" technique, you need fewer error checks in
callers, and buy that with an error check in every callee.  Can be
nice.

However, mixing the two techniques is confusing.  You can't use the
"accumulate" technique with functions designed for the "check
separately" technique.  You can use the "check separately" technique
with functions designed for the "accumulate" technique, but then
error_set() can't catch you setting an error more than once.

Standardize on the "check separately" technique for now, because it's
overwhelmingly prevalent.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-05-15 14:00:46 -04:00
Markus Armbruster f9bee751be qapi: Normalize marshalling's visitor initialization and cleanup
Input and output marshalling functions do it differently.  Change them
to work the same: initialize the I/O visitor, use it, clean it up,
initialize the dealloc visitor, use it, clean it up.

This delays dealloc visitor initialization in output marshalling
functions, and input visitor cleanup in input marshalling functions.
No functional change, but the latter will be convenient when I change
the error handling.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-05-15 14:00:45 -04:00
Markus Armbruster 6e2bb3ec70 qapi: Update qapi-code-gen.txt example to match current code
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-05-15 14:00:45 -04:00
Juan Quintela 35d08458a9 savevm: Remove all the unneeded version_minimum_id_old (rest)
After previous Peter patch, they are redundant.  This way we don't
assign them except when needed.  Once there, there were lots of case
where the ".fields" indentation was wrong:

     .fields = (VMStateField []) {
and
     .fields =      (VMStateField []) {

Change all the combinations to:

     .fields = (VMStateField[]){

The biggest problem (appart from aesthetics) was that checkpatch complained
when we copy&pasted the code from one place to another.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
2014-05-14 15:24:51 +02:00
Eric Blake cc1626556d qapi: Document optional arguments' backwards compatibility
Signed-off-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-05-09 09:11:32 -04:00