Patchwork [RFC,05/14,v9] Add API to get memory mapping

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Submitter Wen Congyang
Date March 14, 2012, 2:07 a.m.
Message ID <4F5FFD74.1060102@cn.fujitsu.com>
Download mbox | patch
Permalink /patch/146523/
State New
Headers show

Comments

Wen Congyang - March 14, 2012, 2:07 a.m.
Add API to get all virtual address and physical address mapping.
If the guest doesn't use paging, the virtual address is equal to the phyical
address. The virtual address and physical address mapping is for gdb's user, and
it does not include the memory that is not referenced by the page table. So if
you want to use crash to anaylze the vmcore, please do not specify -p option.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
---
 memory_mapping.c |   36 ++++++++++++++++++++++++++++++++++++
 memory_mapping.h |    8 ++++++++
 2 files changed, 44 insertions(+), 0 deletions(-)
HATAYAMA Daisuke - March 16, 2012, 3:52 a.m.
From: Wen Congyang <wency@cn.fujitsu.com>
Subject: [RFC][PATCH 05/14 v9] Add API to get memory mapping
Date: Wed, 14 Mar 2012 10:07:48 +0800

>  }
> +
> +int qemu_get_guest_memory_mapping(MemoryMappingList *list)
> +{
> +    CPUState *env;
> +    RAMBlock *block;
> +    ram_addr_t offset, length;
> +    int ret;
> +    bool paging_mode;
> +
> +#if defined(CONFIG_HAVE_GET_MEMORY_MAPPING)
> +    paging_mode = cpu_paging_enabled(first_cpu);
> +    if (paging_mode) {
> +        for (env = first_cpu; env != NULL; env = env->next_cpu) {
> +            ret = cpu_get_memory_mapping(list, env);
> +            if (ret < 0) {
> +                return -1;
> +            }
> +        }
> +        return 0;
> +    }
> +#else
> +    return -2;
> +#endif

Is it better to define the below somewhere else?

#ifndef CONFIG_HAVE_GET_MEMORY_MAPPING
static inline int qemu_get_guest_memory_mapping(MemoryMappingList *list)
{
	return -2;
}
#endif

Thanks.
HATAYAMA, Daisuke
HATAYAMA Daisuke - March 16, 2012, 6:38 a.m.
From: Wen Congyang <wency@cn.fujitsu.com>
Subject: [RFC][PATCH 05/14 v9] Add API to get memory mapping
Date: Wed, 14 Mar 2012 10:07:48 +0800

> Add API to get all virtual address and physical address mapping.
> If the guest doesn't use paging, the virtual address is equal to the phyical
> address. The virtual address and physical address mapping is for gdb's user, and
> it does not include the memory that is not referenced by the page table. So if
> you want to use crash to anaylze the vmcore, please do not specify -p option.

It's necessary to write the reason why the -p option is not default
explicitly: guest machine in a catastrophic state can have corrupted
memory, which we cannot trust.

Thanks.
HATAYAMA, Daisuke
Wen Congyang - March 16, 2012, 6:50 a.m.
At 03/16/2012 11:52 AM, HATAYAMA Daisuke Wrote:
> From: Wen Congyang <wency@cn.fujitsu.com>
> Subject: [RFC][PATCH 05/14 v9] Add API to get memory mapping
> Date: Wed, 14 Mar 2012 10:07:48 +0800
> 
>>  }
>> +
>> +int qemu_get_guest_memory_mapping(MemoryMappingList *list)
>> +{
>> +    CPUState *env;
>> +    RAMBlock *block;
>> +    ram_addr_t offset, length;
>> +    int ret;
>> +    bool paging_mode;
>> +
>> +#if defined(CONFIG_HAVE_GET_MEMORY_MAPPING)
>> +    paging_mode = cpu_paging_enabled(first_cpu);
>> +    if (paging_mode) {
>> +        for (env = first_cpu; env != NULL; env = env->next_cpu) {
>> +            ret = cpu_get_memory_mapping(list, env);
>> +            if (ret < 0) {
>> +                return -1;
>> +            }
>> +        }
>> +        return 0;
>> +    }
>> +#else
>> +    return -2;
>> +#endif
> 
> Is it better to define the below somewhere else?
> 
> #ifndef CONFIG_HAVE_GET_MEMORY_MAPPING
> static inline int qemu_get_guest_memory_mapping(MemoryMappingList *list)
> {
> 	return -2;
> }
> #endif

Yes

Thanks
Wen Congyang

> 
> Thanks.
> HATAYAMA, Daisuke
> 
>
Wen Congyang - March 16, 2012, 6:59 a.m.
At 03/16/2012 02:38 PM, HATAYAMA Daisuke Wrote:
> From: Wen Congyang <wency@cn.fujitsu.com>
> Subject: [RFC][PATCH 05/14 v9] Add API to get memory mapping
> Date: Wed, 14 Mar 2012 10:07:48 +0800
> 
>> Add API to get all virtual address and physical address mapping.
>> If the guest doesn't use paging, the virtual address is equal to the phyical
>> address. The virtual address and physical address mapping is for gdb's user, and
>> it does not include the memory that is not referenced by the page table. So if
>> you want to use crash to anaylze the vmcore, please do not specify -p option.
> 
> It's necessary to write the reason why the -p option is not default
> explicitly: guest machine in a catastrophic state can have corrupted
> memory, which we cannot trust.

Yes

Thanks
Wen Congyang

> 
> Thanks.
> HATAYAMA, Daisuke
> 
>

Patch

diff --git a/memory_mapping.c b/memory_mapping.c
index 718f271..2ae8160 100644
--- a/memory_mapping.c
+++ b/memory_mapping.c
@@ -164,3 +164,39 @@  void memory_mapping_list_init(MemoryMappingList *list)
     list->last_mapping = NULL;
     QTAILQ_INIT(&list->head);
 }
+
+int qemu_get_guest_memory_mapping(MemoryMappingList *list)
+{
+    CPUState *env;
+    RAMBlock *block;
+    ram_addr_t offset, length;
+    int ret;
+    bool paging_mode;
+
+#if defined(CONFIG_HAVE_GET_MEMORY_MAPPING)
+    paging_mode = cpu_paging_enabled(first_cpu);
+    if (paging_mode) {
+        for (env = first_cpu; env != NULL; env = env->next_cpu) {
+            ret = cpu_get_memory_mapping(list, env);
+            if (ret < 0) {
+                return -1;
+            }
+        }
+        return 0;
+    }
+#else
+    return -2;
+#endif
+
+    /*
+     * If the guest doesn't use paging, the virtual address is equal to physical
+     * address.
+     */
+    QLIST_FOREACH(block, &ram_list.blocks, next) {
+        offset = block->offset;
+        length = block->length;
+        create_new_memory_mapping(list, offset, offset, length);
+    }
+
+    return 0;
+}
diff --git a/memory_mapping.h b/memory_mapping.h
index 836b047..ebd7cf6 100644
--- a/memory_mapping.h
+++ b/memory_mapping.h
@@ -44,4 +44,12 @@  void memory_mapping_list_free(MemoryMappingList *list);
 
 void memory_mapping_list_init(MemoryMappingList *list);
 
+/*
+ * Return value:
+ *    0: success
+ *   -1: failed
+ *   -2: unsupported
+ */
+int qemu_get_guest_memory_mapping(MemoryMappingList *list);
+
 #endif