From 8dbe22c6868b8a5efd1df3d0c5150524fabe61ff Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Mon, 10 May 2021 13:43:21 +0200 Subject: memory: Introduce RAM_NORESERVE and wire it up in qemu_ram_mmap() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Let's introduce RAM_NORESERVE, allowing mmap'ing with MAP_NORESERVE. The new flag has the following semantics: " RAM is mmap-ed with MAP_NORESERVE. When set, reserving swap space (or huge pages if applicable) is skipped: will bail out if not supported. When not set, the OS will do the reservation, if supported for the memory type. " Allow passing it into: - memory_region_init_ram_nomigrate() - memory_region_init_resizeable_ram() - memory_region_init_ram_from_file() ... and teach qemu_ram_mmap() and qemu_anon_ram_alloc() about the flag. Bail out if the flag is not supported, which is the case right now for both, POSIX and win32. We will add Linux support next and allow specifying RAM_NORESERVE via memory backends. The target use case is virtio-mem, which dynamically exposes memory inside a large, sparse memory area to the VM. Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Peter Xu Acked-by: Eduardo Habkost for memory backend and machine core Signed-off-by: David Hildenbrand Message-Id: <20210510114328.21835-9-david@redhat.com> Signed-off-by: Paolo Bonzini --- include/exec/cpu-common.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/exec/cpu-common.h') diff --git a/include/exec/cpu-common.h b/include/exec/cpu-common.h index ccabed4003..039d422bf4 100644 --- a/include/exec/cpu-common.h +++ b/include/exec/cpu-common.h @@ -59,6 +59,7 @@ ram_addr_t qemu_ram_get_offset(RAMBlock *rb); ram_addr_t qemu_ram_get_used_length(RAMBlock *rb); ram_addr_t qemu_ram_get_max_length(RAMBlock *rb); bool qemu_ram_is_shared(RAMBlock *rb); +bool qemu_ram_is_noreserve(RAMBlock *rb); bool qemu_ram_is_uf_zeroable(RAMBlock *rb); void qemu_ram_set_uf_zeroable(RAMBlock *rb); bool qemu_ram_is_migratable(RAMBlock *rb); -- cgit 1.4.1