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authorHaozhong Zhang <haozhong.zhang@intel.com>2017-12-11 15:28:04 +0800
committerEduardo Habkost <ehabkost@redhat.com>2018-01-19 11:18:51 -0200
commit983768431676f9ab8599a0b4813e1ca17af70838 (patch)
tree4923d3621cf664db0fe10092321df708f718c84f /memory.c
parent1e2bdd2e20844f6bc343232ea1bb6f64c54a95ce (diff)
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 'memory.c')
-rw-r--r--memory.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/memory.c b/memory.c
index 4b41fb837b..449a1429b9 100644
--- a/memory.c
+++ b/memory.c
@@ -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;
}