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[PULL 08/17] qom: Allow objects to be allocated with increased alignment
From: |
Eduardo Habkost |
Subject: |
[PULL 08/17] qom: Allow objects to be allocated with increased alignment |
Date: |
Fri, 18 Sep 2020 16:47:05 -0400 |
From: Richard Henderson <richard.henderson@linaro.org>
It turns out that some hosts have a default malloc alignment less
than that required for vectors.
We assume that, with compiler annotation on CPUArchState, that we
can properly align the vector portion of the guest state. Fix the
alignment of the allocation by using qemu_memalloc when required.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20200916004638.2444147-3-richard.henderson@linaro.org>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
include/qom/object.h | 5 +++++
qom/object.c | 36 +++++++++++++++++++++++++++++++++---
2 files changed, 38 insertions(+), 3 deletions(-)
diff --git a/include/qom/object.h b/include/qom/object.h
index 32524d72cc..405a2c67b0 100644
--- a/include/qom/object.h
+++ b/include/qom/object.h
@@ -691,6 +691,7 @@ struct Object
.parent = TYPE_##PARENT_MODULE_OBJ_NAME, \
.name = TYPE_##MODULE_OBJ_NAME, \
.instance_size = sizeof(ModuleObjName), \
+ .instance_align = __alignof__(ModuleObjName), \
.instance_init = module_obj_name##_init, \
.instance_finalize = module_obj_name##_finalize, \
.class_size = sizeof(ModuleObjName##Class), \
@@ -770,6 +771,9 @@ struct Object
* @instance_size: The size of the object (derivative of #Object). If
* @instance_size is 0, then the size of the object will be the size of the
* parent object.
+ * @instance_align: The required alignment of the object. If @instance_align
+ * is 0, then normal malloc alignment is sufficient; if non-zero, then we
+ * must use qemu_memalign for allocation.
* @instance_init: This function is called to initialize an object. The parent
* class will have already been initialized so the type is only responsible
* for initializing its own members.
@@ -807,6 +811,7 @@ struct TypeInfo
const char *parent;
size_t instance_size;
+ size_t instance_align;
void (*instance_init)(Object *obj);
void (*instance_post_init)(Object *obj);
void (*instance_finalize)(Object *obj);
diff --git a/qom/object.c b/qom/object.c
index cecad35b99..a91a6a515a 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -50,6 +50,7 @@ struct TypeImpl
size_t class_size;
size_t instance_size;
+ size_t instance_align;
void (*class_init)(ObjectClass *klass, void *data);
void (*class_base_init)(ObjectClass *klass, void *data);
@@ -114,6 +115,7 @@ static TypeImpl *type_new(const TypeInfo *info)
ti->class_size = info->class_size;
ti->instance_size = info->instance_size;
+ ti->instance_align = info->instance_align;
ti->class_init = info->class_init;
ti->class_base_init = info->class_base_init;
@@ -688,16 +690,44 @@ static void object_finalize(void *data)
}
}
+/* Find the minimum alignment guaranteed by the system malloc. */
+#if __STDC_VERSION__ >= 201112L
+typddef max_align_t qemu_max_align_t;
+#else
+typedef union {
+ long l;
+ void *p;
+ double d;
+ long double ld;
+} qemu_max_align_t;
+#endif
+
static Object *object_new_with_type(Type type)
{
Object *obj;
+ size_t size, align;
+ void (*obj_free)(void *);
g_assert(type != NULL);
type_initialize(type);
- obj = g_malloc(type->instance_size);
- object_initialize_with_type(obj, type->instance_size, type);
- obj->free = g_free;
+ size = type->instance_size;
+ align = type->instance_align;
+
+ /*
+ * Do not use qemu_memalign unless required. Depending on the
+ * implementation, extra alignment implies extra overhead.
+ */
+ if (likely(align <= __alignof__(qemu_max_align_t))) {
+ obj = g_malloc(size);
+ obj_free = g_free;
+ } else {
+ obj = qemu_memalign(align, size);
+ obj_free = qemu_vfree;
+ }
+
+ object_initialize_with_type(obj, size, type);
+ obj->free = obj_free;
return obj;
}
--
2.26.2
- [PULL 00/17] QOM queue, 2020-09-18, Eduardo Habkost, 2020/09/18
- [PULL 04/17] sifive: Use DECLARE_*CHECKER* macros, Eduardo Habkost, 2020/09/18
- [PULL 02/17] sifive_u: Rename memmap enum constants, Eduardo Habkost, 2020/09/18
- [PULL 05/17] qom: Correct object_class_dynamic_cast_assert() documentation, Eduardo Habkost, 2020/09/18
- [PULL 01/17] sifive_e: Rename memmap enum constants, Eduardo Habkost, 2020/09/18
- [PULL 08/17] qom: Allow objects to be allocated with increased alignment,
Eduardo Habkost <=
- [PULL 10/17] target/ppc: Set instance_align on PowerPCCPU TypeInfo, Eduardo Habkost, 2020/09/18
- [PULL 03/17] sifive: Move QOM typedefs and add missing includes, Eduardo Habkost, 2020/09/18
- [PULL 07/17] qom: Correct error values in two contracts, Eduardo Habkost, 2020/09/18
- [PULL 06/17] qom: Clean up object_property_get_enum()'s error value, Eduardo Habkost, 2020/09/18
- [PULL 14/17] qom: Remove ParentClassType argument from OBJECT_DECLARE_SIMPLE_TYPE, Eduardo Habkost, 2020/09/18
- [PULL 11/17] target/riscv: Set instance_align on RISCVCPU TypeInfo, Eduardo Habkost, 2020/09/18
- [PULL 09/17] target/arm: Set instance_align on CPUARM TypeInfo, Eduardo Habkost, 2020/09/18
- [PULL 12/17] target/s390x: Set instance_align on S390CPU TypeInfo, Eduardo Habkost, 2020/09/18
- [PULL 13/17] scripts/codeconverter: Update to latest version, Eduardo Habkost, 2020/09/18
- [PULL 15/17] qom: Remove module_obj_name parameter from OBJECT_DECLARE* macros, Eduardo Habkost, 2020/09/18