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path: root/backends/hostmem-memfd.c
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2019-01-07hostmem: use object id for memory region name with >= 4.0Marc-André Lureau
hostmem-file and hostmem-memfd use the whole object path for the memory region name, and hostname-ram uses only the path component (the object id, or canonical path basename): qemu -m 1024 -object memory-backend-file,id=mem,size=1G,mem-path=/tmp/foo -numa node,memdev=mem -monitor stdio (qemu) info ramblock Block Name PSize Offset Used Total /objects/mem 4 KiB 0x0000000000000000 0x0000000040000000 0x0000000040000000 qemu -m 1024 -object memory-backend-memfd,id=mem,size=1G -numa node,memdev=mem -monitor stdio (qemu) info ramblock Block Name PSize Offset Used Total /objects/mem 4 KiB 0x0000000000000000 0x0000000040000000 0x0000000040000000 qemu -m 1024 -object memory-backend-ram,id=mem,size=1G -numa node,memdev=mem -monitor stdio (qemu) info ramblock Block Name PSize Offset Used Total mem 4 KiB 0x0000000000000000 0x0000000040000000 0x0000000040000000 For consistency, change to use object id for -file and -memfd as well with >= 4.0. Having a consistent naming allows to migrate to different hostmem backends. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Igor Mammedov <imammedo@redhat.com> Acked-by: Eduardo Habkost <ehabkost@redhat.com>
2018-11-28hostmem: no need to check for host_memory_backend_mr_inited() in alloc()Marc-André Lureau
memfd_backend_memory_alloc/file_backend_memory_alloc both needlessly are are calling host_memory_backend_mr_inited() which creates an illusion that alloc could be called multiple times but it isn't, it's called once from UserCreatable complete(). Suggested-by: Igor Mammedov <imammedo@redhat.com> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Igor Mammedov <imammedo@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-11-27hostmem-memfd: honour share=on/off propertyMarc-André Lureau
The share=on/off property is used to modified mmap() MAP_SHARED setting. Make it on by default for convenience and compatibility reasons. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-05hostmem: add some properties descriptionMarc-André Lureau
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-02hostmem-memfd: add checks before adding hostmem-memfd & propertiesMarc-André Lureau
Run some memfd-related checks before registering hostmem-memfd & various properties. This will help libvirt to figure out what the host is supposed to be capable of. qemu_memfd_check() is changed to a less optimized version, since it is used with various flags, it no longer caches the result. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <20180906161415.8543-1-marcandre.lureau@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-02-07Add memfd based hostmemMarc-André Lureau
Add a new memory backend, similar to hostmem-file, except that it doesn't need to create files. It also enforces memory sealing. This backend is mainly useful for sharing the memory with other processes. Note that Linux supports transparent huge-pages of shmem/memfd memory since 4.8. It is relatively easier to set up THP than a dedicate hugepage mount point by using "madvise" in /sys/kernel/mm/transparent_hugepage/shmem_enabled. Since 4.14, memfd allows to set hugetlb requirement explicitly. Pending for merge in 4.16 is memfd sealing support for hugetlb backed memory. Usage: -object memory-backend-memfd,id=mem1,size=1G Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <20180201132757.23063-5-marcandre.lureau@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>