diff options
| -rw-r--r-- | backends/hostmem-file.c | 41 | ||||
| -rw-r--r-- | docs/nvdimm.txt | 16 | ||||
| -rw-r--r-- | exec.c | 8 | ||||
| -rw-r--r-- | include/exec/memory.h | 3 | ||||
| -rw-r--r-- | memory.c | 2 | ||||
| -rw-r--r-- | numa.c | 2 | ||||
| -rw-r--r-- | qemu-options.hx | 9 |
7 files changed, 77 insertions, 4 deletions
diff --git a/backends/hostmem-file.c b/backends/hostmem-file.c index e44c319..e319ec1 100644 --- a/backends/hostmem-file.c +++ b/backends/hostmem-file.c @@ -34,6 +34,7 @@ struct HostMemoryBackendFile { bool share; bool discard_data; char *mem_path; + uint64_t align; }; static void @@ -58,7 +59,7 @@ file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) path = object_get_canonical_path(OBJECT(backend)); memory_region_init_ram_from_file(&backend->mr, OBJECT(backend), path, - backend->size, fb->share, + backend->size, fb->align, fb->share, fb->mem_path, errp); g_free(path); } @@ -115,6 +116,40 @@ static void file_memory_backend_set_discard_data(Object *o, bool value, MEMORY_BACKEND_FILE(o)->discard_data = value; } +static void file_memory_backend_get_align(Object *o, Visitor *v, + const char *name, void *opaque, + Error **errp) +{ + HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); + uint64_t val = fb->align; + + visit_type_size(v, name, &val, errp); +} + +static void file_memory_backend_set_align(Object *o, Visitor *v, + const char *name, void *opaque, + Error **errp) +{ + HostMemoryBackend *backend = MEMORY_BACKEND(o); + HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); + Error *local_err = NULL; + uint64_t val; + + if (host_memory_backend_mr_inited(backend)) { + error_setg(&local_err, "cannot change property value"); + goto out; + } + + visit_type_size(v, name, &val, &local_err); + if (local_err) { + goto out; + } + fb->align = val; + + out: + error_propagate(errp, local_err); +} + static void file_backend_unparent(Object *obj) { HostMemoryBackend *backend = MEMORY_BACKEND(obj); @@ -145,6 +180,10 @@ file_backend_class_init(ObjectClass *oc, void *data) object_class_property_add_str(oc, "mem-path", get_mem_path, set_mem_path, &error_abort); + object_class_property_add(oc, "align", "int", + file_memory_backend_get_align, + file_memory_backend_set_align, + NULL, NULL, &error_abort); } static void file_backend_instance_finalize(Object *o) diff --git a/docs/nvdimm.txt b/docs/nvdimm.txt index 2d9f8c0..21249dd 100644 --- a/docs/nvdimm.txt +++ b/docs/nvdimm.txt @@ -122,3 +122,19 @@ Note: M >= size of RAM devices + size of statically plugged vNVDIMM devices + size of hotplugged vNVDIMM devices + +Alignment +--------- + +QEMU uses mmap(2) to maps vNVDIMM backends and aligns the mapping +address to the page size (getpagesize(2)) by default. However, some +types of backends may require an alignment different than the page +size. In that case, QEMU v2.12.0 and later provide 'align' option to +memory-backend-file to allow users to specify the proper alignment. + +For example, device dax require the 2 MB alignment, so we can use +following QEMU command line options to use it (/dev/dax0.0) as the +backend of vNVDIMM: + + -object memory-backend-file,id=mem1,share=on,mem-path=/dev/dax0.0,size=4G,align=2M + -device nvdimm,id=nvdimm1,memdev=mem1 @@ -1612,7 +1612,13 @@ static void *file_ram_alloc(RAMBlock *block, void *area; block->page_size = qemu_fd_getpagesize(fd); - block->mr->align = block->page_size; + if (block->mr->align % block->page_size) { + error_setg(errp, "alignment 0x%" PRIx64 + " must be multiples of page size 0x%zx", + block->mr->align, block->page_size); + return NULL; + } + block->mr->align = MAX(block->page_size, block->mr->align); #if defined(__s390x__) if (kvm_enabled()) { block->mr->align = MAX(block->mr->align, QEMU_VMALLOC_ALIGN); diff --git a/include/exec/memory.h b/include/exec/memory.h index a4cabdf..07c5d6d 100644 --- a/include/exec/memory.h +++ b/include/exec/memory.h @@ -465,6 +465,8 @@ void memory_region_init_resizeable_ram(MemoryRegion *mr, * @name: Region name, becomes part of RAMBlock name used in migration stream * must be unique within any device * @size: size of the region. + * @align: alignment of the region base address; if 0, the default alignment + * (getpagesize()) will be used. * @share: %true if memory must be mmaped with the MAP_SHARED flag * @path: the path in which to allocate the RAM. * @errp: pointer to Error*, to store an error if it happens. @@ -476,6 +478,7 @@ void memory_region_init_ram_from_file(MemoryRegion *mr, struct Object *owner, const char *name, uint64_t size, + uint64_t align, bool share, const char *path, Error **errp); @@ -1570,6 +1570,7 @@ void memory_region_init_ram_from_file(MemoryRegion *mr, struct Object *owner, const char *name, uint64_t size, + uint64_t align, bool share, const char *path, Error **errp) @@ -1578,6 +1579,7 @@ void memory_region_init_ram_from_file(MemoryRegion *mr, mr->ram = true; mr->terminates = true; mr->destructor = memory_region_destructor_ram; + mr->align = align; mr->ram_block = qemu_ram_alloc_from_file(size, mr, share, path, errp); mr->dirty_log_mask = tcg_enabled() ? (1 << DIRTY_MEMORY_CODE) : 0; } @@ -456,7 +456,7 @@ static void allocate_system_memory_nonnuma(MemoryRegion *mr, Object *owner, if (mem_path) { #ifdef __linux__ Error *err = NULL; - memory_region_init_ram_from_file(mr, owner, name, ram_size, false, + memory_region_init_ram_from_file(mr, owner, name, ram_size, 0, false, mem_path, &err); if (err) { error_report_err(err); diff --git a/qemu-options.hx b/qemu-options.hx index b3e03c5..5ff741a 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -3974,7 +3974,7 @@ property must be set. These objects are placed in the @table @option -@item -object memory-backend-file,id=@var{id},size=@var{size},mem-path=@var{dir},share=@var{on|off},discard-data=@var{on|off},merge=@var{on|off},dump=@var{on|off},prealloc=@var{on|off},host-nodes=@var{host-nodes},policy=@var{default|preferred|bind|interleave} +@item -object memory-backend-file,id=@var{id},size=@var{size},mem-path=@var{dir},share=@var{on|off},discard-data=@var{on|off},merge=@var{on|off},dump=@var{on|off},prealloc=@var{on|off},host-nodes=@var{host-nodes},policy=@var{default|preferred|bind|interleave},align=@var{align} Creates a memory file backend object, which can be used to back the guest RAM with huge pages. @@ -4027,6 +4027,13 @@ restrict memory allocation to the given host node list interleave memory allocations across the given host node list @end table +The @option{align} option specifies the base address alignment when +QEMU mmap(2) @option{mem-path}, and accepts common suffixes, eg +@option{2M}. Some backend store specified by @option{mem-path} +requires an alignment different than the default one used by QEMU, eg +the device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In +such cases, users can specify the required alignment via this option. + @item -object memory-backend-ram,id=@var{id},merge=@var{on|off},dump=@var{on|off},prealloc=@var{on|off},size=@var{size},host-nodes=@var{host-nodes},policy=@var{default|preferred|bind|interleave} Creates a memory backend object, which can be used to back the guest RAM. |