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| author | Haozhong Zhang <haozhong.zhang@intel.com> | 2017-12-11 15:28:04 +0800 |
|---|---|---|
| committer | Eduardo Habkost <ehabkost@redhat.com> | 2018-01-19 11:18:51 -0200 |
| commit | 983768431676f9ab8599a0b4813e1ca17af70838 (patch) | |
| tree | 4923d3621cf664db0fe10092321df708f718c84f /include/exec/memory.h | |
| parent | 1e2bdd2e20844f6bc343232ea1bb6f64c54a95ce (diff) | |
| download | qemu-983768431676f9ab8599a0b4813e1ca17af70838.tar.gz | |
hostmem-file: add "align" option
When mmap(2) the backend files, QEMU uses the host page size
(getpagesize(2)) by default as the alignment of mapping address.
However, some backends may require alignments different than the page
size. For example, mmap a device DAX (e.g., /dev/dax0.0) on Linux
kernel 4.13 to an address, which is 4K-aligned but not 2M-aligned,
fails with a kernel message like
[617494.969768] dax dax0.0: qemu-system-x86: dax_mmap: fail, unaligned vma (0x7fa37c579000 - 0x7fa43c579000, 0x1fffff)
Because there is no common approach to get such alignment requirement,
we add the 'align' option to 'memory-backend-file', so that users or
management utils, which have enough knowledge about the backend, can
specify a proper alignment via this option.
Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
Message-Id: <20171211072806.2812-2-haozhong.zhang@intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
[ehabkost: fixed typo, fixed error_setg() format string]
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Diffstat (limited to 'include/exec/memory.h')
| -rw-r--r-- | include/exec/memory.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/exec/memory.h b/include/exec/memory.h index a4cabdf44c..07c5d6d597 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); |