From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Chen, Tiejun" <tiejun.chen@intel.com>
Subject: Re: [RFC][PATCH 10/13] tools: extend
	XENMEM_set_memory_map
Date: Tue, 14 Apr 2015 08:42:39 +0800
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To: Wei Liu <wei.liu2@citrix.com>
Cc: kevin.tian@intel.com, ian.campbell@citrix.com, andrew.cooper3@citrix.com, tim@xen.org, xen-devel@lists.xen.org, stefano.stabellini@citrix.com, JBeulich@suse.com, yang.z.zhang@intel.com, Ian.Jackson@eu.citrix.com
List-Id: xen-devel@lists.xenproject.org

On 2015/4/13 19:02, Wei Liu wrote:
> On Mon, Apr 13, 2015 at 10:09:51AM +0800, Chen, Tiejun wrote:
> [...]
>>> Hardcoded value?
>>
>> Yes. Actually, we intend to use this to present that lowmem entry,
>>
>> tools/firmware/hvmloader/e820.c:
>>
>>      /* Low RAM goes here. Reserve space for special pages. */
>>      ...
>>      e820[nr].addr = 0x100000;
>>
>
> I don't like the idea of having two hardcoded values in different

Just one place since based on our logic, hvmloader doesn't have this 
setting anymore and actually it really grab that info from here. Please 
refer to patch #13.

> locations. Please put this value into a header file and reference it
> here and in hvmloader.

Anyway, I'd like to define this here directly since no one consumes this 
again.

diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c
index 5134b33..af747e6 100644
--- a/tools/libxl/libxl_dom.c
+++ b/tools/libxl/libxl_dom.c
@@ -787,6 +787,7 @@ out:
      return rc;
  }

+#define GUEST_LOW_MEM_START_DEFAULT 0x100000
  static int libxl__domain_construct_memmap(libxl__gc *gc,
                                            libxl_domain_config *d_config,
                                            uint32_t domid,
@@ -812,8 +813,8 @@ static int libxl__domain_construct_memmap(libxl__gc *gc,
      e820 = libxl__malloc(gc, sizeof(struct e820entry) * e820_entries);

      /* Low memory */
-    e820[nr].addr = 0x100000;
-    e820[nr].size = args->lowmem_size - 0x100000;
+    e820[nr].addr = GUEST_LOW_MEM_START_DEFAULT;
+    e820[nr].size = args->lowmem_size - GUEST_LOW_MEM_START_DEFAULT;
      e820[nr].type = E820_RAM;
      nr++;

Is this fine to you?

Thanks
Tiejun