Re: [Xen-devel] question about xc_get_pfn_list() - tgh - com.xensource.lists.xen-devel

5 messages in com.xensource.lists.xen-develRe: [Xen-devel] question about xc_get...

From	Sent On	Attachments
Zhao, Yunfeng	12 Mar 2007 19:53	.txt, .txt
tgh	12 Mar 2007 20:32
tgh	15 Mar 2007 20:46
Daniel Stodden	16 Mar 2007 03:35
tgh	16 Mar 2007 05:36

Subject:	Re: [Xen-devel] question about xc_get_pfn_list()
From:	tgh (tian...@ncic.ac.cn)
Date:	03/16/2007 05:36:39 AM
List:	com.xensource.lists.xen-devel

Thank you for your guide and now I find the related code I have read this part code of xen3.0.2 a few days ago,but did not understand it well and I read this part code in xen3.0.3 this time ,and there are some change in this part I am confused by the difference between my memory and the code,and thank you for your guide I look through it

Thank you for help

Daniel Stodden 写道:

On Fri, 2007-03-16 at 11:46 +0800, tgh wrote:

hi I try to understand the code of VMcreate

not sure what VMcreate means. are you looking at the xend code?

where does the xc_get_pfn_list( ) further go to? I am confused does xc_get_pfn_list finally go to the function arch_do_domctl() or not? I am lost in the xc_get_pfn_list()

huh? unless you're not looking at x86_32/64, it's carrying quite a blatant call to do_domct() right in the middle :). [tools/libxc/xc_private.c]

this goes to arch_do_domctl() in xen, with cmd DOMCTL_getmemlist.

and the function of xc_get_pfn_list() is to allocate the phymemframe to the VM which is going to be booted up ,am I right?

no. it receives the machine frame numbers (mfns) of all the pages allocated by the domain. as an array, which in turn may span several pages, depending on the vm size.

the number of pages needed to carry the entire mfn list can be determined from xc_domain_getinfo().

I am confused about it

no need to despair. get yourself a good utility for browsing code and following the function definitions. it will get better, quickly. :)

regards, daniel