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* First batch of MAINTAINERS updates
* IOAPIC fixes (to pass kvm-unit-tests with -machine kernel_irqchip=off)
* NBD API upgrades from Daniel
* strtosz fixes from Marc-André
* improved support for readonly=on on scsi-generic devices
* new "info ioapic" and "info lapic" monitor commands
* Peter Crosthwaite's ELF_MACHINE cleanups
* docs patches from Thomas and Daniel
# gpg: Signature made Fri 25 Sep 2015 11:20:52 BST using RSA key ID 78C7AE83
# gpg: Good signature from "Paolo Bonzini <bonzini@gnu.org>"
# gpg: aka "Paolo Bonzini <pbonzini@redhat.com>"
* remotes/bonzini/tags/for-upstream: (52 commits)
doc: Refresh URLs in the qemu-tech documentation
docs: describe the QEMU build system structure / design
typedef: add typedef for QemuOpts
i386: interrupt poll processing
i386: partial revert of interrupt poll fix
ppc: Rename ELF_MACHINE to be PPC specific
i386: Rename ELF_MACHINE to be x86 specific
alpha: Remove ELF_MACHINE from cpu.h
mips: Remove ELF_MACHINE from cpu.h
sparc: Remove ELF_MACHINE from cpu.h
s390: Remove ELF_MACHINE from cpu.h
sh4: Remove ELF_MACHINE from cpu.h
xtensa: Remove ELF_MACHINE from cpu.h
tricore: Remove ELF_MACHINE from cpu.h
or32: Remove ELF_MACHINE from cpu.h
lm32: Remove ELF_MACHINE from cpu.h
unicore: Remove ELF_MACHINE from cpu.h
moxie: Remove ELF_MACHINE from cpu.h
cris: Remove ELF_MACHINE from cpu.h
m68k: Remove ELF_MACHINE from cpu.h
...
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
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virtio,pc features, fixes
New features:
vhost-user multiqueue support
virtio-ccw virtio 1 support
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
# gpg: Signature made Fri 25 Sep 2015 07:40:35 BST using RSA key ID D28D5469
# gpg: Good signature from "Michael S. Tsirkin <mst@kernel.org>"
# gpg: aka "Michael S. Tsirkin <mst@redhat.com>"
* remotes/mst/tags/for_upstream:
MAINTAINERS: add more devices to the PCI section
MAINTAINERS: add more devices to the PC section
vhost-user: add a new message to disable/enable a specific virt queue.
vhost-user: add multiple queue support
vhost: introduce vhost_backend_get_vq_index method
vhost-user: add VHOST_USER_GET_QUEUE_NUM message
vhost: rename VHOST_RESET_OWNER to VHOST_RESET_DEVICE
vhost-user: add protocol feature negotiation
vhost-user: use VHOST_USER_XXX macro for switch statement
virtio-ccw: enable virtio-1
virtio-ccw: feature bits > 31 handling
virtio-ccw: support ring size changes
virtio: ring sizes vs. reset
pc: Introduce pc-*-2.5 machine classes
q35: Move options common to all classes to pc_i440fx_machine_options()
q35: Move options common to all classes to pc_q35_machine_options()
virtio-net: unbreak self announcement and guest offloads after migration
virtio: right size for virtio_queue_get_avail_size
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
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Developers who are new to QEMU, or have a background familiarity
with GNU autotools, can have trouble getting their head around the
home-grown QEMU build system. This document attempts to explain
the structure / design of the configure script and the various
Makefile pieces that live across the source tree.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1443102098-13642-1-git-send-email-berrange@redhat.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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QemuEvents are used heavily by call_rcu. We do not want them to be slow,
but the current implementation does a kernel call on every invocation
of qemu_event_* and won't cut it.
So, wrap a Win32 manual-reset event with a fast userspace path. The
states and transitions are the same as for the futex and mutex/condvar
implementations, but the slow path is different of course. The idea
is to reset the Win32 event lazily, as part of a test-reset-test-wait
sequence. Such a sequence is, indeed, how QemuEvents are used by
RCU and other subsystems!
The patch includes a formal model of the algorithm.
Tested-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Weil <sw@weilnetz.de>
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Add a new message, VHOST_USER_SET_VRING_ENABLE, to enable or disable
a specific virt queue, which is similar to attach/detach queue for
tap device.
virtio driver on guest doesn't have to use max virt queue pair, it
could enable any number of virt queue ranging from 1 to max virt
queue pair.
Signed-off-by: Changchun Ouyang <changchun.ouyang@intel.com>
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Reviewed-by: Jason Wang <jasowang@redhat.com>
Tested-by: Marcel Apfelbaum <marcel@redhat.com>
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This patch is initially based a patch from Nikolay Nikolaev.
This patch adds vhost-user multiple queue support, by creating a nc
and vhost_net pair for each queue.
Qemu exits if find that the backend can't support the number of requested
queues (by providing queues=# option). The max number is queried by a
new message, VHOST_USER_GET_QUEUE_NUM, and is sent only when protocol
feature VHOST_USER_PROTOCOL_F_MQ is present first.
The max queue check is done at vhost-user initiation stage. We initiate
one queue first, which, in the meantime, also gets the max_queues the
backend supports.
In older version, it was reported that some messages are sent more times
than necessary. Here we came an agreement with Michael that we could
categorize vhost user messages to 2 types: non-vring specific messages,
which should be sent only once, and vring specific messages, which should
be sent per queue.
Here I introduced a helper function vhost_user_one_time_request(), which
lists following messages as non-vring specific messages:
VHOST_USER_SET_OWNER
VHOST_USER_RESET_DEVICE
VHOST_USER_SET_MEM_TABLE
VHOST_USER_GET_QUEUE_NUM
For above messages, we simply ignore them when they are not sent the first
time.
Signed-off-by: Nikolay Nikolaev <n.nikolaev@virtualopensystems.com>
Signed-off-by: Changchun Ouyang <changchun.ouyang@intel.com>
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Reviewed-by: Jason Wang <jasowang@redhat.com>
Tested-by: Marcel Apfelbaum <marcel@redhat.com>
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This is for querying how many queues the backend supports if it has mq
support(when VHOST_USER_PROTOCOL_F_MQ flag is set from the quried
protocol features).
vhost_net_get_max_queues() is the interface to export that value, and
to tell if the backend supports # of queues user requested, which is
done in the following patch.
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Tested-by: Marcel Apfelbaum <marcel@redhat.com>
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Quote from Michael:
We really should rename VHOST_RESET_OWNER to VHOST_RESET_DEVICE.
Suggested-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Reviewed-by: Marcel Apfelbaum <marcel@redhat.com>
Tested-by: Marcel Apfelbaum <marcel@redhat.com>
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Support a separate bitmask for vhost-user protocol features,
and messages to get/set protocol features.
Invoke them at init.
No features are defined yet.
[ leverage vhost_user_call for request handling -- Yuanhan Liu ]
Signed-off-by: Michael S. Tsirkin <address@hidden>
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Reviewed-by: Marcel Apfelbaum <marcel@redhat.com>
Tested-by: Marcel Apfelbaum <marcel@redhat.com>
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libcacard is now a standalone project hosted with the Spice project (see
the 2.5.0 release announcement), remove it from qemu tree.
Use the library if found during configure or if --enable-smartcard.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Tested-by: Paolo Bonzini <pbonzini@redhat.com>
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Parse ibm,architecture.vec table obtained from the guest and enable
memory node configuration via ibm,dynamic-reconfiguration-memory if guest
supports it. This is in preparation to support memory hotplug for
sPAPR guests.
This changes the way memory node configuration is done. Currently all
memory nodes are built upfront. But after this patch, only memory@0 node
for RMA is built upfront. Guest kernel boots with just that and rest of
the memory nodes (via memory@XXX or ibm,dynamic-reconfiguration-memory)
are built when guest does ibm,client-architecture-support call.
Note: This patch needs a SLOF enhancement which is already part of
SLOF binary in QEMU.
Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
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To eliminate the temptation for clients to look up types by name
(which are not ABI), replace all type names by meaningless strings.
Reduces output of query-schema by 13 out of 85KiB.
As a debugging aid, provide option -u to suppress the hiding.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <1442401589-24189-27-git-send-email-armbru@redhat.com>
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qapi/introspect.json defines the introspection schema. It's designed
for QMP introspection, but should do for similar uses, such as QGA.
The introspection schema does not reflect all the rules and
restrictions that apply to QAPI schemata. A valid QAPI schema has an
introspection value conforming to the introspection schema, but the
converse is not true.
Introspection lowers away a number of schema details, and makes
implicit things explicit:
* The built-in types are declared with their JSON type.
All integer types are mapped to 'int', because how many bits we use
internally is an implementation detail. It could be pressed into
external interface service as very approximate range information,
but that's a bad idea. If we need range information, we better do
it properly.
* Implicit type definitions are made explicit, and given
auto-generated names:
- Array types, named by appending "List" to the name of their
element type, like in generated C.
- The enumeration types implicitly defined by simple union types,
named by appending "Kind" to the name of their simple union type,
like in generated C.
- Types that don't occur in generated C. Their names start with ':'
so they don't clash with the user's names.
* All type references are by name.
* The struct and union types are generalized into an object type.
* Base types are flattened.
* Commands take a single argument and return a single result.
Dictionary argument or list result is an implicit type definition.
The empty object type is used when a command takes no arguments or
produces no results.
The argument is always of object type, but the introspection schema
doesn't reflect that.
The 'gen': false directive is omitted as implementation detail.
The 'success-response' directive is omitted as well for now, even
though it's not an implementation detail, because it's not used by
QMP.
* Events carry a single data value.
Implicit type definition and empty object type use, just like for
commands.
The value is of object type, but the introspection schema doesn't
reflect that.
* Types not used by commands or events are omitted.
Indirect use counts as use.
* Optional members have a default, which can only be null right now
Instead of a mandatory "optional" flag, we have an optional default.
No default means mandatory, default null means optional without
default value. Non-null is available for optional with default
(possible future extension).
* Clients should *not* look up types by name, because type names are
not ABI. Look up the command or event you're interested in, then
follow the references.
TODO Should we hide the type names to eliminate the temptation?
New generator scripts/qapi-introspect.py computes an introspection
value for its input, and generates a C variable holding it.
It can generate awfully long lines. Marked TODO.
A new test-qmp-input-visitor test case feeds its result for both
tests/qapi-schema/qapi-schema-test.json and qapi-schema.json to a
QmpInputVisitor to verify it actually conforms to the schema.
New QMP command query-qmp-schema takes its return value from that
variable. Its reply is some 85KiBytes for me right now.
If this turns out to be too much, we have a couple of options:
* We can use shorter names in the JSON. Not the QMP style.
* Optionally return the sub-schema for commands and events given as
arguments.
Right now qmp_query_schema() sends the string literal computed by
qmp-introspect.py. To compute sub-schema at run time, we'd have to
duplicate parts of qapi-introspect.py in C. Unattractive.
* Let clients cache the output of query-qmp-schema.
It changes only on QEMU upgrades, i.e. rarely. Provide a command
query-qmp-schema-hash. Clients can have a cache indexed by hash,
and re-query the schema only when they don't have it cached. Even
simpler: put the hash in the QMP greeting.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
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'gen': false needs to stay for now, because netdev_add is still using
it.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1442401589-24189-25-git-send-email-armbru@redhat.com>
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It doesn't take a 'props' argument, let alone one in the format
"NAME=VALUE,..."
The bogus arguments specification doesn't matter due to 'gen': false.
Clean it up to be incomplete rather than wrong, and document the
incompleteness.
While there, improve netdev_add usage example in the manual: add a
device option to show how it's done.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1442401589-24189-24-git-send-email-armbru@redhat.com>
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It's first class, because unlike '**', it actually works, i.e. doesn't
require 'gen': false.
'**' will go away next.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
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Clarify how they map to JSON. Add how they map to C. Fix the
reference to StringInputVisitor.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1442401589-24189-20-git-send-email-armbru@redhat.com>
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gen_marshal_output() uses its parameter name only for name of the
generated function. Name it after the type being marshaled instead of
its caller, and drop duplicates.
Saves 7 copies of qmp_marshal_output_int() in qemu-ga, and one copy of
qmp_marshal_output_str() in qemu-system-*.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1442401589-24189-19-git-send-email-armbru@redhat.com>
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These functions marshal both input and output.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1442401589-24189-17-git-send-email-armbru@redhat.com>
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Generate just 'FOO' instead of 'struct FOO' when possible.
Drop helper functions that are now unused.
Make pep8 and pylint reasonably happy.
Rename generate_FOO() functions to gen_FOO() for consistency.
Use more consistent and sensible variable names.
Consistently use c_ for mapping keys when their value is a C
identifier or type.
Simplify gen_enum() and gen_visit_union()
Consistently use single quotes for C text string literals.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1442401589-24189-14-git-send-email-armbru@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
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Duplicated in commit 21cd70d. Yes, we can't import qapi-types, but
that's no excuse. Move the helpers from qapi-types.py to qapi.py, and
replace the duplicates in qapi-event.py.
The generated event enumeration type's lookup table becomes
const-correct (see commit 2e4450f), and uses explicit indexes instead
of relying on order (see commit 912ae9c).
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1442401589-24189-10-git-send-email-armbru@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
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Fixes flat unions to get the base's base members. Test case is from
commit 2fc0043, in qapi-schema-test.json:
{ 'union': 'UserDefFlatUnion',
'base': 'UserDefUnionBase',
'discriminator': 'enum1',
'data': { 'value1' : 'UserDefA',
'value2' : 'UserDefB',
'value3' : 'UserDefB' } }
{ 'struct': 'UserDefUnionBase',
'base': 'UserDefZero',
'data': { 'string': 'str', 'enum1': 'EnumOne' } }
{ 'struct': 'UserDefZero',
'data': { 'integer': 'int' } }
Patch's effect on UserDefFlatUnion:
struct UserDefFlatUnion {
/* Members inherited from UserDefUnionBase: */
+ int64_t integer;
char *string;
EnumOne enum1;
/* Own members: */
union { /* union tag is @enum1 */
void *data;
UserDefA *value1;
UserDefB *value2;
UserDefB *value3;
};
};
Flat union visitors remain broken. They'll be fixed next.
Code is generated in a different order now, but that doesn't matter.
The two guards QAPI_TYPES_BUILTIN_STRUCT_DECL and
QAPI_TYPES_BUILTIN_CLEANUP_DECL are replaced by just
QAPI_TYPES_BUILTIN.
Two ugly special cases for simple unions now stand out like sore
thumbs:
1. The type tag is named 'type' everywhere, except in generated C,
where it's 'kind'.
2. QAPISchema lowers simple unions to semantically equivalent flat
unions. However, the C generated for a simple unions differs from
the C generated for its equivalent flat union, and we therefore
need special code to preserve that pointless difference for now.
Mark both TODO.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
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The camel_to_upper() method applies some heuristics to turn
a mixed case type name into an all-uppercase name. This is
used for example, to generate enum constant name prefixes.
The heuristics don't also generate a satisfactory name
though. eg
{ 'enum': 'QCryptoTLSCredsEndpoint',
'data': ['client', 'server']}
Results in Q_CRYPTOTLS_CREDS_ENDPOINT_CLIENT. This has
an undesirable _ after the initial Q and is missing an
_ between the CRYPTO & TLS strings.
Rather than try to add more and more heuristics to try
to cope with this, simply allow the QAPI schema to
specify the desired enum constant prefix explicitly.
eg
{ 'enum': 'QCryptoTLSCredsEndpoint',
'prefix': 'QCRYPTO_TLS_CREDS_ENDPOINT',
'data': ['client', 'server']}
Now gives the QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT name.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
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Signed-off-by: Veres Lajos <vlajos@gmail.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
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Many source files have doubled words (eg "the the", "to to",
and so on). Most of these can simply be removed, but a couple
were actual mis-spellings (eg "to to" instead of "to do").
There was even one triple word score "to to to" :-)
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
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QEMU has options to configure the size of the L2 and refcount
caches for the qcow2 format. However, choosing the right sizes for
a particular disk image is not a straightforward operation since
the ratio between the cache size and the allocated disk space is
not obvious and depends on the size of the cluster and the refcount
entries.
This document attempts to give an overview of both caches and how to
configure their sizes.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 55de928e139b1ba3f3d40fe9c6c88f30b1f36410.1438690126.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
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Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
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Clean up white-space, brace placement, and superfluous #ifdef
QAPI_TYPES_BUILTIN_CLEANUP_DEF.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
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In generated command handlers, the assignment to retval dominates its
only use. Therefore, its initialization is useless. Drop it.
Suggested-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
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Reproducer: with
{ 'command': 'user_def_cmd4', 'returns': { 'a': 'int' } }
added to qapi-schema-test.json, qapi-commands.py dies when it tries to
generate the command handler function
Traceback (most recent call last):
File "/work/armbru/qemu/scripts/qapi-commands.py", line 359, in <module>
ret = generate_command_decl(cmd['command'], arglist, ret_type) + "\n"
File "/work/armbru/qemu/scripts/qapi-commands.py", line 29, in generate_command_decl
ret_type=c_type(ret_type), name=c_name(name),
File "/work/armbru/qemu/scripts/qapi.py", line 927, in c_type
assert isinstance(value, str) and value != ""
AssertionError
because the return type doesn't exist.
Simply outlaw this usage, and drop or dumb down test cases accordingly.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
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A command's or event's 'data' must be a struct type, given either as a
dictionary, or as struct type name.
Commit dd883c6 tightened the checking there, but not enough: we still
accept 'union'. Fix to reject it.
We may want to support union types there, but we'll have to extend
qapi-commands.py and qapi-events.py for it.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
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Use c_name() instead of ad hoc code. Doesn't upcase the -p prefix,
which is an improvement in my book. Unbreaks prefix containing '.',
but other funny characters remain broken. To be fixed next.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
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It's idempotent.
While there, update examples to current code.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
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It is pretty rare for aio_notify to actually set the EventNotifier. It
can happen with worker threads such as thread-pool.c's, but otherwise it
should never be set thanks to the ctx->notify_me optimization. The
previous patch, unfortunately, added an unconditional call to
event_notifier_test_and_clear; now add a userspace fast path that
avoids the call.
Note that it is not possible to do the same with event_notifier_set;
it would break, as proved (again) by the included formal model.
This patch survived over 3000 reboots on aarch64 KVM.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
Message-id: 1437487673-23740-7-git-send-email-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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event_notifier_test_and_clear must be called before processing events.
Otherwise, an aio_poll could "eat" the notification before the main
I/O thread invokes ppoll(). The main I/O thread then never wakes up.
This is an example of what could happen:
i/o thread vcpu thread worker thread
---------------------------------------------------------------------
lock_iothread
notify_me = 1
...
unlock_iothread
bh->scheduled = 1
event_notifier_set
lock_iothread
notify_me = 3
ppoll
notify_me = 1
aio_dispatch
aio_bh_poll
thread_pool_completion_bh
bh->scheduled = 1
event_notifier_set
node->io_read(node->opaque)
event_notifier_test_and_clear
ppoll
*** hang ***
"Tracing" with qemu_clock_get_ns shows pretty much the same behavior as
in the previous bug, so there are no new tricks here---just stare more
at the code until it is apparent.
One could also use a formal model, of course. The included one shows
this with three processes: notifier corresponds to a QEMU thread pool
worker, temporary_waiter to a VCPU thread that invokes aio_poll(),
waiter to the main I/O thread. I would be happy to say that the
formal model found the bug for me, but actually I wrote it after the
fact.
This patch is a bit of a big hammer. The next one optimizes it,
with help (this time for real rather than a posteriori :)) from
another, similar formal model.
Reported-by: Richard W. M. Jones <rjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
Message-id: 1437487673-23740-6-git-send-email-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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This patch rewrites the ctx->dispatching optimization, which was the cause
of some mysterious hangs that could be reproduced on aarch64 KVM only.
The hangs were indirectly caused by aio_poll() and in particular by
flash memory updates's call to blk_write(), which invokes aio_poll().
Fun stuff: they had an extremely short race window, so much that
adding all kind of tracing to either the kernel or QEMU made it
go away (a single printf made it half as reproducible).
On the plus side, the failure mode (a hang until the next keypress)
made it very easy to examine the state of the process with a debugger.
And there was a very nice reproducer from Laszlo, which failed pretty
often (more than half of the time) on any version of QEMU with a non-debug
kernel; it also failed fast, while still in the firmware. So, it could
have been worse.
For some unknown reason they happened only with virtio-scsi, but
that's not important. It's more interesting that they disappeared with
io=native, making thread-pool.c a likely suspect for where the bug arose.
thread-pool.c is also one of the few places which use bottom halves
across threads, by the way.
I hope that no other similar bugs exist, but just in case :) I am
going to describe how the successful debugging went... Since the
likely culprit was the ctx->dispatching optimization, which mostly
affects bottom halves, the first observation was that there are two
qemu_bh_schedule() invocations in the thread pool: the one in the aio
worker and the one in thread_pool_completion_bh. The latter always
causes the optimization to trigger, the former may or may not. In
order to restrict the possibilities, I introduced new functions
qemu_bh_schedule_slow() and qemu_bh_schedule_fast():
/* qemu_bh_schedule_slow: */
ctx = bh->ctx;
bh->idle = 0;
if (atomic_xchg(&bh->scheduled, 1) == 0) {
event_notifier_set(&ctx->notifier);
}
/* qemu_bh_schedule_fast: */
ctx = bh->ctx;
bh->idle = 0;
assert(ctx->dispatching);
atomic_xchg(&bh->scheduled, 1);
Notice how the atomic_xchg is still in qemu_bh_schedule_slow(). This
was already debated a few months ago, so I assumed it to be correct.
In retrospect this was a very good idea, as you'll see later.
Changing thread_pool_completion_bh() to qemu_bh_schedule_fast() didn't
trigger the assertion (as expected). Changing the worker's invocation
to qemu_bh_schedule_slow() didn't hide the bug (another assumption
which luckily held). This already limited heavily the amount of
interaction between the threads, hinting that the problematic events
must have triggered around thread_pool_completion_bh().
As mentioned early, invoking a debugger to examine the state of a
hung process was pretty easy; the iothread was always waiting on a
poll(..., -1) system call. Infinite timeouts are much rarer on x86,
and this could be the reason why the bug was never observed there.
With the buggy sequence more or less resolved to an interaction between
thread_pool_completion_bh() and poll(..., -1), my "tracing" strategy was
to just add a few qemu_clock_get_ns(QEMU_CLOCK_REALTIME) calls, hoping
that the ordering of aio_ctx_prepare(), aio_ctx_dispatch, poll() and
qemu_bh_schedule_fast() would provide some hint. The output was:
(gdb) p last_prepare
$3 = 103885451
(gdb) p last_dispatch
$4 = 103876492
(gdb) p last_poll
$5 = 115909333
(gdb) p last_schedule
$6 = 115925212
Notice how the last call to qemu_poll_ns() came after aio_ctx_dispatch().
This makes little sense unless there is an aio_poll() call involved,
and indeed with a slightly different instrumentation you can see that
there is one:
(gdb) p last_prepare
$3 = 107569679
(gdb) p last_dispatch
$4 = 107561600
(gdb) p last_aio_poll
$5 = 110671400
(gdb) p last_schedule
$6 = 110698917
So the scenario becomes clearer:
iothread VCPU thread
--------------------------------------------------------------------------
aio_ctx_prepare
aio_ctx_check
qemu_poll_ns(timeout=-1)
aio_poll
aio_dispatch
thread_pool_completion_bh
qemu_bh_schedule()
At this point bh->scheduled = 1 and the iothread has not been woken up.
The solution must be close, but this alone should not be a problem,
because the bottom half is only rescheduled to account for rare situations
(see commit 3c80ca1, thread-pool: avoid deadlock in nested aio_poll()
calls, 2014-07-15).
Introducing a third thread---a thread pool worker thread, which
also does qemu_bh_schedule()---does bring out the problematic case.
The third thread must be awakened *after* the callback is complete and
thread_pool_completion_bh has redone the whole loop, explaining the
short race window. And then this is what happens:
thread pool worker
--------------------------------------------------------------------------
<I/O completes>
qemu_bh_schedule()
Tada, bh->scheduled is already 1, so qemu_bh_schedule() does nothing
and the iothread is never woken up. This is where the bh->scheduled
optimization comes into play---it is correct, but removing it would
have masked the bug.
So, what is the bug?
Well, the question asked by the ctx->dispatching optimization ("is any
active aio_poll dispatching?") was wrong. The right question to ask
instead is "is any active aio_poll *not* dispatching", i.e. in the prepare
or poll phases? In that case, the aio_poll is sleeping or might go to
sleep anytime soon, and the EventNotifier must be invoked to wake
it up.
In any other case (including if there is *no* active aio_poll at all!)
we can just wait for the next prepare phase to pick up the event (e.g. a
bottom half); the prepare phase will avoid the blocking and service the
bottom half.
Expressing the invariant with a logic formula, the broken one looked like:
!(exists(thread): in_dispatching(thread)) => !optimize
or equivalently:
!(exists(thread):
in_aio_poll(thread) && in_dispatching(thread)) => !optimize
In the correct one, the negation is in a slightly different place:
(exists(thread):
in_aio_poll(thread) && !in_dispatching(thread)) => !optimize
or equivalently:
(exists(thread): in_prepare_or_poll(thread)) => !optimize
Even if the difference boils down to moving an exclamation mark :)
the implementation is quite different. However, I think the new
one is simpler to understand.
In the old implementation, the "exists" was implemented with a boolean
value. This didn't really support well the case of multiple concurrent
event loops, but I thought that this was okay: aio_poll holds the
AioContext lock so there cannot be concurrent aio_poll invocations, and
I was just considering nested event loops. However, aio_poll _could_
indeed be concurrent with the GSource. This is why I came up with the
wrong invariant.
In the new implementation, "exists" is computed simply by counting how many
threads are in the prepare or poll phases. There are some interesting
points to consider, but the gist of the idea remains:
1) AioContext can be used through GSource as well; as mentioned in the
patch, bit 0 of the counter is reserved for the GSource.
2) the counter need not be updated for a non-blocking aio_poll, because
it won't sleep forever anyway. This is just a matter of checking
the "blocking" variable. This requires some changes to the win32
implementation, but is otherwise not too complicated.
3) as mentioned above, the new implementation will not call aio_notify
when there is *no* active aio_poll at all. The tests have to be
adjusted for this change. The calls to aio_notify in async.c are fine;
they only want to kick aio_poll out of a blocking wait, but need not
do anything if aio_poll is not running.
4) nested aio_poll: these just work with the new implementation; when
a nested event loop is invoked, the outer event loop is never in the
prepare or poll phases. The outer event loop thus has already decremented
the counter.
Reported-by: Richard W. M. Jones <rjones@redhat.com>
Reported-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
Message-id: 1437487673-23740-5-git-send-email-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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This reverts commit 830d70db692e374b55555f4407f96a1ceefdcc97.
The interface isn't fully backwards-compatible, which is bad.
Let's redo this properly after 2.4.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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into staging
Patch queue for ppc - 2015-07-07
A few last minute PPC changes for 2.4:
- spapr: Update SLOF
- spapr: Fix a few bugs
- spapr: Preparation for hotplug
- spapr: Minor code cleanups
- linux-user: Add mftb handling
- kvm: Enable hugepage support with memory-backend-file
- mac99: Remove nonexistent interrupt pin (Mac OS 9 fix)
# gpg: Signature made Tue Jul 7 16:48:41 2015 BST using RSA key ID 03FEDC60
# gpg: Good signature from "Alexander Graf <agraf@suse.de>"
# gpg: aka "Alexander Graf <alex@csgraf.de>"
* remotes/agraf/tags/signed-ppc-for-upstream: (30 commits)
sPAPR: Clear stale MSIx table during EEH reset
sPAPR: Reenable EEH functionality on reboot
sPAPR: Don't enable EEH on emulated PCI devices
spapr-vty: Use TYPE_ definition instead of hardcoding
spapr_vty: lookup should only return valid VTY objects
spapr_pci: drop redundant args in spapr_[populate, create]_pci_child_dt
spapr_pci: populate ibm,loc-code
spapr_pci: enumerate and add PCI device tree
xics_kvm: Don't enable KVM_CAP_IRQ_XICS if already enabled
ppc: Update cpu_model in MachineState
spapr: Consolidate cpu init code into a routine
spapr: Reorganize CPU dt generation code
cpus: Add a macro to walk CPUs in reverse
spapr: Support ibm, lrdr-capacity device tree property
spapr: Consider max_cpus during xics initialization
Revert "hw/ppc/spapr_pci.c: Avoid functions not in glib 2.12 (g_hash_table_iter_*)"
spapr_iommu: translate sPAPRTCEAccess to IOMMUAccessFlags
spapr_iommu: drop erroneous check in h_put_tce_indirect()
spapr_pci: set device node unit address as hex
spapr_pci: encode class code including Prog IF register
...
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
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into staging
migration/next for 20150707
# gpg: Signature made Tue Jul 7 13:56:30 2015 BST using RSA key ID 5872D723
# gpg: Good signature from "Juan Quintela <quintela@redhat.com>"
# gpg: aka "Juan Quintela <quintela@trasno.org>"
* remotes/juanquintela/tags/migration/20150707: (28 commits)
migration: extend migration_bitmap
migration: protect migration_bitmap
check_section_footers: Check the correct section_id
migration: Add migration events on target side
migration: Make events a capability
migration: create migration event
migration: No need to call trace_migrate_set_state()
migration: Use always helper to set state
migration: ensure we start in NONE state
migration: Use cmpxchg correctly
migration: Add configuration section
vmstate: Create optional sections
global_state: Make section optional
migration: create new section to store global state
runstate: migration allows more transitions now
runstate: Add runstate store
Fix older machine type compatibility on power with section footers
Fail more cleanly in mismatched RAM cases
Sanity check RDMA remote data
Sort destination RAMBlocks to be the same as the source
...
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
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Add support for ibm,lrdr-capacity since this is needed by the guest
kernel to know about the possible hot-pluggable CPUs and Memory. With
this, pseries kernels will start reporting correct maxcpus in
/sys/devices/system/cpu/possible.
Also define the minimum hotpluggable memory size as 256MB.
Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
[agraf: Fix compile error on 32bit hosts]
Signed-off-by: Alexander Graf <agraf@suse.de>
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We have one argument that tells us what event has happened.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
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For pkts copied to the CPU (to be processed by guest driver), mark the Rx
descriptor with flag "OFFLOAD_FWD" to indicate device has already forwarded
pkt. The guest driver will use this indicator to avoid duplicate
forwarding in the guest OS.
Examples include bcast/mcast/unknown ucast pkts flooded to bridged ports.
We want to avoid both the device and the guest bridge driver flooding these
pkts, which would result in duplicates pkts on the wire. Packet sampling,
such as sFlow, can also use this technique to mark pkts for the guest OS to
record but otherwise drop.
Signed-off-by: Scott Feldman <sfeldma@gmail.com>
Message-id: 1435746792-41278-5-git-send-email-sfeldma@gmail.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
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Add display and head properties for input routing to
virtio-input devices, update multiseat documentation.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
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If we wish to make differential backups a feature that's easy to access,
it might be pertinent to rename the "dirty-bitmap" mode to "incremental"
to make it clear what /type/ of backup the dirty-bitmap is helping us
perform.
This is an API breaking change, but 2.4 has not yet gone live,
so we have this flexibility.
Signed-off-by: John Snow <jsnow@redhat.com>
Message-id: 1433463642-21840-2-git-send-email-jsnow@redhat.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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Simplifies multiseat configuration, see
docs/multiseat.txt update for details.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Commit 87a560c4 added it in the wrong place. Commit 59a2c4ce added it
in the right place, but didn't remove it from the wrong place. Do
that now.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
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staging
# gpg: Signature made Fri Jun 12 13:57:20 2015 BST using RSA key ID 81AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>"
# gpg: aka "Stefan Hajnoczi <stefanha@gmail.com>"
* remotes/stefanha/tags/net-pull-request:
qmp/hmp: add rocker device support
rocker: bring link up/down on PHY enable/disable
rocker: update tests using hw-derived interface names
rocker: Add support for phys name
iohandler: Change return type of qemu_set_fd_handler to "void"
event-notifier: Always return 0 for posix implementation
xen_backend: Remove unused error handling of qemu_set_fd_handler
oss: Remove unused error handling of qemu_set_fd_handler
alsaaudio: Remove unused error handling of qemu_set_fd_handler
main-loop: Drop qemu_set_fd_handler2
Change qemu_set_fd_handler2(..., NULL, ...) to qemu_set_fd_handler
tap: Drop tap_can_send
net/socket: Drop net_socket_can_send
netmap: Drop netmap_can_send
l2tpv3: Drop l2tpv3_can_send
stubs: Add qemu_set_fd_handler
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
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Add ROCKER_TLV_CMD_PORT_SETTINGS_PHYS_NAME to port settings. This attribute
exports the port name to the guest OS allowing it to name interfaces with
sensible defaults.
Mostly done by Scott for phys_id support; adapted to phys_name by David.
Signed-off-by: Scott Feldman <sfeldma@gmail.com>
Signed-off-by: David Ahern <dsahern@gmail.com>
Message-id: 1433985681-56138-2-git-send-email-sfeldma@gmail.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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We create optional sections with this patch. But we already have
optional subsections. Instead of having two mechanism that do the
same, we can just generalize it.
For subsections we just change:
- Add a needed function to VMStateDescription
- Remove VMStateSubsection (after removal of the needed function
it is just a VMStateDescription)
- Adjust the whole tree, moving the needed function to the corresponding
VMStateDescription
Signed-off-by: Juan Quintela <quintela@redhat.com>
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