qemu/qapi
Stefano Garzarella 4e647fa085 hostmem: add a new memory backend based on POSIX shm_open()
shm_open() creates and opens a new POSIX shared memory object.
A POSIX shared memory object allows creating memory backend with an
associated file descriptor that can be shared with external processes
(e.g. vhost-user).

The new `memory-backend-shm` can be used as an alternative when
`memory-backend-memfd` is not available (Linux only), since shm_open()
should be provided by any POSIX-compliant operating system.

This backend mimics memfd, allocating memory that is practically
anonymous. In theory shm_open() requires a name, but this is allocated
for a short time interval and shm_unlink() is called right after
shm_open(). After that, only fd is shared with external processes
(e.g., vhost-user) as if it were associated with anonymous memory.

In the future we may also allow the user to specify the name to be
passed to shm_open(), but for now we keep the backend simple, mimicking
anonymous memory such as memfd.

Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Markus Armbruster <armbru@redhat.com> (QAPI schema)
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Message-Id: <20240618100519.145853-1-sgarzare@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-07-03 18:14:06 -04:00
..
acpi.json qapi: Require descriptions and tagged sections to be indented 2024-02-26 10:43:56 +01:00
audio.json audio/pw: Pipewire->PipeWire case fix for user-visible text 2023-07-17 15:22:56 +04:00
authz.json qapi: Reformat doc comments to conform to current conventions 2023-05-10 10:01:01 +02:00
block-core.json qapi: blockdev-backup: add discard-source parameter 2024-05-28 15:52:15 +03:00
block-export.json qapi: Move error documentation to new "Errors" sections 2024-03-04 07:12:40 +01:00
block.json qapi: Refill doc comments to conform to current conventions 2024-03-26 06:36:08 +01:00
char.json qapi: Delete useless "Returns" sections 2024-03-04 07:12:40 +01:00
common.json qapi: document PCIe Gen5/Gen6 speeds since 9.0 2024-03-18 04:57:45 -04:00
compat.json qapi: Belatedly update CompatPolicy documentation for unstable 2023-10-19 07:02:29 +02:00
control.json qapi: Drop stray Arguments: line from qmp_capabilities docs 2024-03-26 06:36:08 +01:00
crypto.json qapi: Correct documentation indentation and whitespace 2024-03-26 06:36:08 +01:00
cryptodev.json spelling: information 2023-06-09 23:38:16 +03:00
cxl.json hw/cxl/events: Add qmp interfaces to add/release dynamic capacity extents 2024-07-01 17:16:04 -04:00
dump.json qapi: Correct documentation indentation and whitespace 2024-03-26 06:36:08 +01:00
ebpf.json qapi: Refill doc comments to conform to current conventions 2024-03-26 06:36:08 +01:00
error.json qapi: Reformat doc comments to conform to current conventions 2023-05-10 10:01:01 +02:00
introspect.json qapi: Drop redundant documentation of inherited members 2024-02-03 09:19:25 +01:00
job.json blockjob: introduce block-job-change QMP command 2023-10-31 18:20:25 +01:00
machine-common.json CPU topology: extend with s390 specifics 2023-10-20 07:16:53 +02:00
machine-target.json target/s390x: report deprecated-props in cpu-model-expansion reply 2024-05-10 08:34:20 +02:00
machine.json hw/intc: Introduce x-query-interrupt-controllers QMP command 2024-06-19 12:40:49 +02:00
meson.build qapi/vfio: Add VFIO migration QAPI event 2024-05-16 16:59:19 +02:00
migration.json migration/postcopy: Add postcopy-recover-setup phase 2024-06-21 09:47:59 -03:00
misc-target.json i386/sev: Update query-sev QAPI format to handle SEV-SNP 2024-06-05 11:01:06 +02:00
misc.json qapi: Correct documentation indentation and whitespace 2024-03-26 06:36:08 +01:00
net.json qapi: Refill doc comments to conform to current conventions 2024-03-26 06:36:08 +01:00
opts-visitor.c qapi: Inline and remove QERR_INVALID_PARAMETER definition 2024-04-24 09:50:58 +02:00
pci.json qapi: Require descriptions and tagged sections to be indented 2024-02-26 10:43:56 +01:00
pragma.json qapi: document parameters of query-cpu-model-* QAPI commands 2024-03-26 06:36:08 +01:00
qapi-clone-visitor.c qapi: Do not cast function pointers 2024-05-29 12:41:56 +02:00
qapi-dealloc-visitor.c qapi: Make visitor functions taking Error ** return bool, not void 2020-07-10 15:18:08 +02:00
qapi-forward-visitor.c qapi: remove needless include 2022-03-22 14:46:18 +04:00
qapi-schema.json qapi/vfio: Add VFIO migration QAPI event 2024-05-16 16:59:19 +02:00
qapi-type-helpers.c qapi: New strv_from_str_list() 2024-03-04 07:12:40 +01:00
qapi-util.c qapi: Fix dangling references to docs/devel/qapi-code-gen.txt 2024-01-26 07:04:53 +01:00
qapi-visit-core.c qapi: Factor out compat_policy_input_ok() 2021-10-29 21:27:20 +02:00
qdev.json qapi: Delete useless "Returns" sections 2024-03-04 07:12:40 +01:00
qmp-dispatch.c Revert "monitor: use aio_co_reschedule_self()" 2024-06-10 11:05:43 +02:00
qmp-event.c Replace qemu_gettimeofday() with g_get_real_time() 2022-04-06 10:50:37 +02:00
qmp-registry.c qapi: Generalize command policy checking 2021-10-29 18:24:46 +02:00
qobject-input-visitor.c qapi: Inline QERR_INVALID_PARAMETER_TYPE definition (constant value) 2024-04-24 09:50:58 +02:00
qobject-output-visitor.c qapi: Extend -compat to set policy for unstable interfaces 2021-10-29 21:28:01 +02:00
qom.json hostmem: add a new memory backend based on POSIX shm_open() 2024-07-03 18:14:06 -04:00
replay.json qapi: Expand a few awkward abbreviations in documentation 2024-03-26 06:36:08 +01:00
rocker.json qapi: Require descriptions and tagged sections to be indented 2024-02-26 10:43:56 +01:00
run-state.json pvpanic: Emit GUEST_PVSHUTDOWN QMP event on pvpanic shutdown signal 2024-07-01 17:16:04 -04:00
sockets.json qapi: Correct documentation indentation and whitespace 2024-03-26 06:36:08 +01:00
stats.json qapi: document leftover members in qapi/stats.json 2024-03-26 06:36:08 +01:00
string-input-visitor.c qapi: Inline QERR_INVALID_PARAMETER_TYPE definition (constant value) 2024-04-24 09:50:58 +02:00
string-output-visitor.c string-output-visitor: Fix (pseudo) struct handling 2024-01-26 11:16:58 +01:00
tpm.json qapi: Delete useless "Returns" sections 2024-03-04 07:12:40 +01:00
trace-events qapi: Generalize struct member policy checking 2021-10-29 18:23:09 +02:00
trace.h trace: switch position of headers to what Meson requires 2020-08-21 06:18:24 -04:00
trace.json trace: Remove deprecated 'vcpu' field from QMP trace events 2024-06-04 11:53:43 +02:00
transaction.json qapi: Delete useless "Returns" sections 2024-03-04 07:12:40 +01:00
ui.json qapi: document InputMultiTouchType 2024-03-26 06:36:08 +01:00
vfio.json qapi/vfio: Add VFIO migration QAPI event 2024-05-16 16:59:19 +02:00
virtio.json qapi: Refill doc comments to conform to current conventions 2024-03-26 06:36:08 +01:00
yank.json qapi/yank: Tweak @yank's error description for consistency 2024-03-04 07:12:40 +01:00