Re: [Qemu-devel] [RFC][PATCH 02/16 v6] Add API to create memory mapping list

[Wen Congyang <wency@cn.fujitsu.com>]

At 02/15/2012 12:39 AM, Jan Kiszka Wrote:
> On 2012-02-09 04:20, Wen Congyang wrote:
>> The memory mapping list stores virtual address and physical address mapping.
>> The folloing patch will use this information to create PT_LOAD in the vmcore.
>>
>> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
>> ---
>>  Makefile.target  |    1 +
>>  memory_mapping.c |  130 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>  memory_mapping.h |   38 ++++++++++++++++
>>  3 files changed, 169 insertions(+), 0 deletions(-)
>>  create mode 100644 memory_mapping.c
>>  create mode 100644 memory_mapping.h
>>
>> diff --git a/Makefile.target b/Makefile.target
>> index 68481a3..e35e464 100644
>> --- a/Makefile.target
>> +++ b/Makefile.target
>> @@ -200,6 +200,7 @@ obj-$(CONFIG_KVM) += kvm.o kvm-all.o
>>  obj-$(CONFIG_NO_KVM) += kvm-stub.o
>>  obj-$(CONFIG_VGA) += vga.o
>>  obj-y += memory.o savevm.o
>> +obj-y += memory_mapping.o
>>  LIBS+=-lz
>>  
>>  obj-i386-$(CONFIG_KVM) += hyperv.o
>> diff --git a/memory_mapping.c b/memory_mapping.c
>> new file mode 100644
>> index 0000000..d83b7d7
>> --- /dev/null
>> +++ b/memory_mapping.c
>> @@ -0,0 +1,130 @@
>> +/*
>> + * QEMU memory mapping
>> + *
>> + * Copyright Fujitsu, Corp. 2011
>> + *
>> + * Authors:
>> + *     Wen Congyang <wency@cn.fujitsu.com>
>> + *
>> + * This work is licensed under the terms of the GNU GPL, version 2.  See
>> + * the COPYING file in the top-level directory.
>> + *
>> + */
>> +
>> +#include "cpu.h"
>> +#include "cpu-all.h"
>> +#include "memory_mapping.h"
>> +
>> +static MemoryMapping *last_mapping;
>> +
>> +static void create_new_memory_mapping(MemoryMappingList *list,
>> +                                      target_phys_addr_t phys_addr,
>> +                                      target_phys_addr_t virt_addr,
>> +                                      ram_addr_t length)
>> +{
>> +    MemoryMapping *memory_mapping, *p;
>> +
>> +    memory_mapping = g_malloc(sizeof(MemoryMapping));
>> +    memory_mapping->phys_addr = phys_addr;
>> +    memory_mapping->virt_addr = virt_addr;
>> +    memory_mapping->length = length;
>> +    last_mapping = memory_mapping;
>> +    list->num++;
>> +    QTAILQ_FOREACH(p, &list->head, next) {
>> +        if (p->phys_addr >= memory_mapping->phys_addr) {
>> +            QTAILQ_INSERT_BEFORE(p, memory_mapping, next);
>> +            return;
>> +        }
>> +    }
>> +    QTAILQ_INSERT_TAIL(&list->head, memory_mapping, next);
>> +    return;
>> +}
>> +
>> +void create_new_memory_mapping_head(MemoryMappingList *list,
>> +                                    target_phys_addr_t phys_addr,
>> +                                    target_phys_addr_t virt_addr,
>> +                                    ram_addr_t length)
>> +{
>> +    MemoryMapping *memory_mapping;
>> +
>> +    memory_mapping = g_malloc(sizeof(MemoryMapping));
>> +    memory_mapping->phys_addr = phys_addr;
>> +    memory_mapping->virt_addr = virt_addr;
>> +    memory_mapping->length = length;
>> +    last_mapping = memory_mapping;
>> +    list->num++;
>> +    QTAILQ_INSERT_HEAD(&list->head, memory_mapping, next);
>> +    return;
>> +}
>> +
>> +void add_to_memory_mapping(MemoryMappingList *list,
>> +                           target_phys_addr_t phys_addr,
>> +                           target_phys_addr_t virt_addr,
>> +                           ram_addr_t length)
>> +{
>> +    MemoryMapping *memory_mapping;
>> +
>> +    if (QTAILQ_EMPTY(&list->head)) {
>> +        create_new_memory_mapping(list, phys_addr, virt_addr, length);
>> +        return;
>> +    }
>> +
>> +    if (last_mapping) {
>> +        if ((phys_addr == (last_mapping->phys_addr + last_mapping->length)) &&
>> +            (virt_addr == (last_mapping->virt_addr + last_mapping->length))) {
>> +            last_mapping->length += length;
>> +            return;
>> +        }
>> +    }
>> +
>> +    QTAILQ_FOREACH(memory_mapping, &list->head, next) {
>> +        last_mapping = memory_mapping;
>> +        if ((phys_addr == (last_mapping->phys_addr + last_mapping->length)) &&
>> +            (virt_addr == (last_mapping->virt_addr + last_mapping->length))) {
>> +            last_mapping->length += length;
>> +            return;
>> +        }
>> +
>> +        if (!(phys_addr >= (last_mapping->phys_addr)) ||
>> +            !(phys_addr < (last_mapping->phys_addr + last_mapping->length))) {
>> +            /* last_mapping does not contain this region */
>> +            continue;
>> +        }
>> +        if (!(virt_addr >= (last_mapping->virt_addr)) ||
>> +            !(virt_addr < (last_mapping->virt_addr + last_mapping->length))) {
>> +            /* last_mapping does not contain this region */
>> +            continue;
>> +        }
>> +        if ((virt_addr - last_mapping->virt_addr) !=
>> +            (phys_addr - last_mapping->phys_addr)) {
>> +            /*
>> +             * last_mapping contains this region, but we should create another
>> +             * mapping region.
>> +             */
>> +            break;
>> +        }
>> +
>> +        /* merge this region into last_mapping */
>> +        if ((virt_addr + length) >
>> +            (last_mapping->virt_addr + last_mapping->length)) {
>> +            last_mapping->length = virt_addr + length - last_mapping->virt_addr;
>> +        }
>> +        return;
>> +    }
>> +
>> +    /* this region can not be merged into any existed memory mapping. */
>> +    create_new_memory_mapping(list, phys_addr, virt_addr, length);
>> +    return;
>> +}
>> +
>> +void free_memory_mapping_list(MemoryMappingList *list)
>> +{
>> +    MemoryMapping *p, *q;
>> +
>> +    QTAILQ_FOREACH_SAFE(p, &list->head, next, q) {
>> +        QTAILQ_REMOVE(&list->head, p, next);
>> +        g_free(p);
>> +    }
>> +
>> +    list->num = 0;
>> +}
>> diff --git a/memory_mapping.h b/memory_mapping.h
>> new file mode 100644
>> index 0000000..a4b1532
>> --- /dev/null
>> +++ b/memory_mapping.h
>> @@ -0,0 +1,38 @@
>> +#ifndef MEMORY_MAPPING_H
>> +#define MEMORY_MAPPING_H
>> +
>> +#include "qemu-queue.h"
>> +
>> +typedef struct MemoryMapping {
>> +    target_phys_addr_t phys_addr;
>> +    target_ulong virt_addr;
>> +    ram_addr_t length;
>> +    QTAILQ_ENTRY(MemoryMapping) next;
>> +} MemoryMapping;
>> +
>> +typedef struct MemoryMappingList {
>> +    unsigned int num;
> 
> This field looks unused by this series. Unless I miss something, you
> probably want to drop it.

It is used in patch 09/16. I need it to calculate the PT_LOAD's num.

> 
>> +    QTAILQ_HEAD(, MemoryMapping) head;
>> +} MemoryMappingList;
>> +
>> +/*
>> + * crash needs some memory mapping should be at the head of the list. It will
>> + * cause the list is not sorted. So the caller must add the special memory
>> + * mapping after adding all the normal memory mapping into list.
>> + */
>> +void create_new_memory_mapping_head(MemoryMappingList *list,
>> +                                    target_phys_addr_t phys_addr,
>> +                                    target_phys_addr_t virt_addr,
>> +                                    ram_addr_t length);
>> +/*
>> + * add or merge the memory region into the memory mapping's list. The list is
>> + * sorted by phys_addr.
>> + */
>> +void add_to_memory_mapping(MemoryMappingList *list,
>> +                           target_phys_addr_t phys_addr,
>> +                           target_phys_addr_t virt_addr,
>> +                           ram_addr_t length);
>> +
>> +void free_memory_mapping_list(MemoryMappingList *list);
>> +
>> +#endif
> 
> A bit hard to understand and use the API. I would suggest:

Sorry for confusing you. I will change the API's name.

> 
> memory_mapping_list_add_sorted(MemoryMappingList *list, ...);
> memory_mapping_list_add_head(MemoryMappingList *list, ...);
> memory_mapping_list_free(MemoryMappingList *list);
> 
> memory_mapping_list_add_head should set a flag in the MemoryMapping
> appended to the list or let the MemoryMappingList point to the firs
> sorted entry. That way, the adding order becomes irrelevant.

Agree with it.

> 
> Moreover, you are lacking some
> memory_mapping_list_init(MemoryMappingList *list). Cleaner than
> open-coding this.

A useful API, and I will add it.
Thanks
Wen Congyang

> 
> Jan
>