@@ -33,6 +33,7 @@ struct HostMemoryBackendFile {
bool share;
char *mem_path;
+ uint64_t align;
};
static void
@@ -57,7 +58,7 @@ 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);
}
@@ -104,6 +105,40 @@ static void file_memory_backend_set_share(Object *o, bool value, Error **errp)
}
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_class_init(ObjectClass *oc, void *data)
{
HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc);
@@ -116,6 +151,10 @@ 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)
@@ -1549,7 +1549,13 @@ static void *file_ram_alloc(RAMBlock *block,
}
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 "
+ "multiple of page size 0x%" PRIx64,
+ block->mr->align, block->page_size);
+ goto error;
+ }
+ 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);
@@ -441,6 +441,7 @@ 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.
* @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.
@@ -449,6 +450,7 @@ 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);
@@ -1386,6 +1386,7 @@ 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)
@@ -1394,6 +1395,7 @@ 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;
}
@@ -541,7 +541,7 @@ 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);
file_ram_alloc() currently maps the backend file via mmap to a virtual address aligned to the value returned by qemu_fd_getpagesize(). When a DAX device (e.g. /dev/dax0.0) is used as the backend file, its kernel mmap implementation may require an alignment larger than what qemu_fd_get_pagesize() returns (e.g. 2MB vs. 4KB), and mmap may fail. This commit adds an attribute 'align' to hostmem-file, so that users can specify a proper alignment that satisfies the kernel requirement. If 'align' is not specified or is 0, the value returned by qemu_fd_get_pagesize() will be used as before. Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com> --- Cc: Eduardo Habkost <ehabkost@redhat.com> Cc: Igor Mammedov <imammedo@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Peter Crosthwaite <crosthwaite.peter@gmail.com> Cc: Richard Henderson <rth@twiddle.net> Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com> Cc: Stefan Hajnoczi <stefanha@gmail.com> Cc: Dan Williams <dan.j.williams@intel.com> --- backends/hostmem-file.c | 41 ++++++++++++++++++++++++++++++++++++++++- exec.c | 8 +++++++- include/exec/memory.h | 2 ++ memory.c | 2 ++ numa.c | 2 +- 5 files changed, 52 insertions(+), 3 deletions(-)