From: Wen Congyang <we...@cn.fujitsu.com>
Subject: [RFC][PATCH 04/14 v7] Add API to get memory mapping
Date: Thu, 01 Mar 2012 10:43:13 +0800
> +int qemu_get_guest_memory_mapping(MemoryMappingList *list)
> +{
> + CPUState *env;
> + MemoryMapping *memory_mapping;
> + RAMBlock *block;
> + ram_addr_t offset, length;
> + int ret;
> +
> +#if defined(CONFIG_HAVE_GET_MEMORY_MAPPING)
> + for (env = first_cpu; env != NULL; env = env->next_cpu) {
> + ret = cpu_get_memory_mapping(list, env);
> + if (ret < 0) {
> + return -1;
> + }
> + }
> +#else
> + return -2;
> +#endif
> +
> + /* some memory may be not mapped, add them into memory mapping's list */
The part from here is logic fully for 2nd kernel? If so, I think it
better to describe why this addtional mapping is needed; we should
assume most people doesn't know kdump mechanism.
> + QLIST_FOREACH(block, &ram_list.blocks, next) {
> + offset = block->offset;
> + length = block->length;
> +
> + QTAILQ_FOREACH(memory_mapping, &list->head, next) {
> + if (memory_mapping->phys_addr >= (offset + length)) {
> + /*
> + * memory_mapping's list does not conatin the region
> + * [offset, offset+length)
> + */
> + create_new_memory_mapping(list, offset, 0, length);
> + length = 0;
> + break;
> + }
> +
> + if ((memory_mapping->phys_addr + memory_mapping->length) <=
> + offset) {
> + continue;
> + }
> +
> + if (memory_mapping->phys_addr > offset) {
> + /*
> + * memory_mapping's list does not conatin the region
> + * [offset, memory_mapping->phys_addr)
> + */
> + create_new_memory_mapping(list, offset, 0,
> + memory_mapping->phys_addr -
> offset);
> + }
> +
> + if ((offset + length) <=
> + (memory_mapping->phys_addr + memory_mapping->length)) {
> + length = 0;
> + break;
> + }
> + length -= memory_mapping->phys_addr + memory_mapping->length -
> + offset;
> + offset = memory_mapping->phys_addr + memory_mapping->length;
> + }
> +
> + if (length > 0) {
> + /*
> + * memory_mapping's list does not conatin the region
> + * [offset, memory_mapping->phys_addr)
> + */
> + create_new_memory_mapping(list, offset, 0, length);
> + }
> + }
> +
> + return 0;
> +}
I think it more readable if shortening memory_mapping->phys_addr and
memmory_maping->length at the berinning of the innermost foreach loop.
m_phys_addr = memory_mapping->phys_addr;
m_length = memory_mapping->length;
Then, each conditionals becomes compact.
Thanks.
HATAYAMA, Daisuke
