Merge tag 'pull-misc-2022-12-14' of https://repo.or.cz/qemu/armbru into staging

Miscellaneous patches for 2022-12-14

# gpg: Signature made Wed 14 Dec 2022 15:23:02 GMT
# gpg: using R

Merge tag 'pull-misc-2022-12-14' of https://repo.or.cz/qemu/armbru into staging

Miscellaneous patches for 2022-12-14

# gpg: Signature made Wed 14 Dec 2022 15:23:02 GMT
# gpg: using RSA key 354BC8B3D7EB2A6B68674E5F3870B400EB918653
# gpg: issuer "armbru@redhat.com"
# gpg: Good signature from "Markus Armbruster <armbru@redhat.com>" [full]
# gpg: aka "Markus Armbruster <armbru@pond.sub.org>" [full]
# Primary key fingerprint: 354B C8B3 D7EB 2A6B 6867 4E5F 3870 B400 EB91 8653

* tag 'pull-misc-2022-12-14' of https://repo.or.cz/qemu/armbru:
ppc4xx_sdram: Simplify sdram_ddr_size() to return
block/vmdk: Simplify vmdk_co_create() to return directly
cleanup: Tweak and re-run return_directly.cocci
io: Tidy up fat-fingered parameter name
qapi: Use returned bool to check for failure (again)
sockets: Use ERRP_GUARD() where obviously appropriate
qemu-config: Use ERRP_GUARD() where obviously appropriate
qemu-config: Make config_parse_qdict() return bool
monitor: Use ERRP_GUARD() in monitor_init()
monitor: Simplify monitor_fd_param()'s error handling
error: Move ERRP_GUARD() to the beginning of the function
error: Drop a few superfluous ERRP_GUARD()
error: Drop some obviously superfluous error_propagate()
Drop more useless casts from void * to pointer

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

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qapi: Use returned bool to check for failure (again)

Commit 012d4c96e2 changed the visitor functions taking Error ** to
return bool instead of void, and the commits following it used the new
return

qapi: Use returned bool to check for failure (again)

Commit 012d4c96e2 changed the visitor functions taking Error ** to
return bool instead of void, and the commits following it used the new
return value to simplify error checking. Since then a few more uses
in need of the same treatment crept in. Do that. All pretty
mechanical except for

* balloon_stats_get_all()

This is basically the same transformation commit 012d4c96e2 applied
to the virtual walk example in include/qapi/visitor.h.

* set_max_queue_size()

Additionally replace "goto end of function" by return.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20221121085054.683122-10-armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

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Merge tag 'mem-2022-10-28' of https://github.com/davidhildenbrand/qemu into staging

Hi,

"Host Memory Backends" and "Memory devices" queue ("mem"):
- Fix NVDIMM error message
- Add ThreadContext use

Merge tag 'mem-2022-10-28' of https://github.com/davidhildenbrand/qemu into staging

Hi,

"Host Memory Backends" and "Memory devices" queue ("mem"):
- Fix NVDIMM error message
- Add ThreadContext user-creatable object and wire it up for NUMA-aware
hostmem preallocation

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# gpg: Signature made Fri 28 Oct 2022 05:44:16 EDT
# gpg: using RSA key 1BD9CAAD735C4C3A460DFCCA4DDE10F700FF835A
# gpg: issuer "david@redhat.com"
# gpg: Good signature from "David Hildenbrand <david@redhat.com>" [unknown]
# gpg: aka "David Hildenbrand <davidhildenbrand@gmail.com>" [full]
# gpg: aka "David Hildenbrand <hildenbr@in.tum.de>" [unknown]
# gpg: WARNING: The key's User ID is not certified with a trusted signature!
# gpg: There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 1BD9 CAAD 735C 4C3A 460D FCCA 4DDE 10F7 00FF 835A

* tag 'mem-2022-10-28' of https://github.com/davidhildenbrand/qemu:
vl: Allow ThreadContext objects to be created before the sandbox option
hostmem: Allow for specifying a ThreadContext for preallocation
util: Make qemu_prealloc_mem() optionally consume a ThreadContext
util: Add write-only "node-affinity" property for ThreadContext
util: Introduce ThreadContext user-creatable object
util: Introduce qemu_thread_set_affinity() and qemu_thread_get_affinity()
util: Cleanup and rename os_mem_prealloc()
hw/mem/nvdimm: fix error message for 'unarmed' flag

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

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util: Add write-only "node-affinity" property for ThreadContext

Let's make it easier to pin threads created via a ThreadContext to
all host CPUs currently belonging to a given set of host NUMA nodes

util: Add write-only "node-affinity" property for ThreadContext

Let's make it easier to pin threads created via a ThreadContext to
all host CPUs currently belonging to a given set of host NUMA nodes --
which is the common case.

"node-affinity" is simply a shortcut for setting "cpu-affinity" manually
to the list of host CPUs belonging to the set of host nodes. This property
can only be written.

A simple QEMU example to set the CPU affinity to host node 1 on a system
with two nodes, 24 CPUs each, whereby odd-numbered host CPUs belong to
host node 1:
qemu-system-x86_64 -S \
-object thread-context,id=tc1,node-affinity=1

And we can query the cpu-affinity via HMP/QMP:
(qemu) qom-get tc1 cpu-affinity
[
1,
3,
5,
7,
9,
11,
13,
15,
17,
19,
21,
23,
25,
27,
29,
31,
33,
35,
37,
39,
41,
43,
45,
47
]

We cannot query the node-affinity:
(qemu) qom-get tc1 node-affinity
Error: Insufficient permission to perform this operation

But note that due to dynamic library loading this example will not work
before we actually make use of thread_context_create_thread() in QEMU
code, because the type will otherwise not get registered. We'll wire
this up next to make it work.

Note that if the host CPUs for a host node change due do CPU hot(un)plug
CPU onlining/offlining (i.e., lscpu output changes) after the ThreadContext
was started, the CPU affinity will not get updated.

Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20221014134720.168738-5-david@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>

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util: Introduce ThreadContext user-creatable object

Setting the CPU affinity of QEMU threads is a bit problematic, because
QEMU doesn't always have permissions to set the CPU affinity itself,
for ex

util: Introduce ThreadContext user-creatable object

Setting the CPU affinity of QEMU threads is a bit problematic, because
QEMU doesn't always have permissions to set the CPU affinity itself,
for example, with seccomp after initialized by QEMU:
-sandbox enable=on,resourcecontrol=deny

General information about CPU affinities can be found in the man page of
taskset:
CPU affinity is a scheduler property that "bonds" a process to a given
set of CPUs on the system. The Linux scheduler will honor the given CPU
affinity and the process will not run on any other CPUs.

While upper layers are already aware of how to handle CPU affinities for
long-lived threads like iothreads or vcpu threads, especially short-lived
threads, as used for memory-backend preallocation, are more involved to
handle. These threads are created on demand and upper layers are not even
able to identify and configure them.

Introduce the concept of a ThreadContext, that is essentially a thread
used for creating new threads. All threads created via that context
thread inherit the configured CPU affinity. Consequently, it's
sufficient to create a ThreadContext and configure it once, and have all
threads created via that ThreadContext inherit the same CPU affinity.

The CPU affinity of a ThreadContext can be configured two ways:

(1) Obtaining the thread id via the "thread-id" property and setting the
CPU affinity manually (e.g., via taskset).

(2) Setting the "cpu-affinity" property and letting QEMU try set the
CPU affinity itself. This will fail if QEMU doesn't have permissions
to do so anymore after seccomp was initialized.

A simple QEMU example to set the CPU affinity to host CPU 0,1,6,7 would be:
qemu-system-x86_64 -S \
-object thread-context,id=tc1,cpu-affinity=0-1,cpu-affinity=6-7

And we can query it via HMP/QMP:
(qemu) qom-get tc1 cpu-affinity
[
0,
1,
6,
7
]

But note that due to dynamic library loading this example will not work
before we actually make use of thread_context_create_thread() in QEMU
code, because the type will otherwise not get registered. We'll wire
this up next to make it work.

In general, the interface behaves like pthread_setaffinity_np(): host
CPU numbers that are currently not available are ignored; only host CPU
numbers that are impossible with the current kernel will fail. If the
list of host CPU numbers does not include a single CPU that is
available, setting the CPU affinity will fail.

A ThreadContext can be reused, simply by reconfiguring the CPU affinity.
Note that the CPU affinity of previously created threads will not get
adjusted.

Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20221014134720.168738-4-david@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>

show more ...