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Re: [Xen-devel] question about xc_get_pfn_list()

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. :)


Daniel Stodden
LRR     -      Lehrstuhl für Rechnertechnik und Rechnerorganisation
Institut für Informatik der TU München             D-85748 Garching
http://www.lrr.in.tum.de/~stodden         mailto:stodden@xxxxxxxxxx
PGP Fingerprint: F5A4 1575 4C56 E26A 0B33  3D80 457E 82AE B0D8 735B

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