From mboxrd@z Thu Jan  1 00:00:00 1970
From: Anastassios Nanos <ananos@cslab.ece.ntua.gr>
Subject: vmap granted pages
Date: Tue, 29 May 2012 17:26:57 +0300
Message-ID: <4FC4DCB1.5040601@cslab.ece.ntua.gr>
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Hi,

I'm trying to reconstruct a user-level, virtually contiguous space
from guest A to guest B using pages that have been granted.

Is this possible with vmap ? I was thinking something like the following:

guest A:

a) get vaddr from userspace, construct page_list
b) grant each page to guest B (using for instance the following):

for each page:
mfn = pfn_to_mfn(page_to_pfn(page));
gref = gnttab_grant_foreign_access(domid, mfn, 0);

(magically transfer nr_pages and grefs to guest B)

guest B:

c) accept the grants and construct a page_list

for each page:
pages <- {accept grant}

d) create a kernel virtual space that is comprised by the previous
page_list:

vaddr = vmap(page_list, nr_pages, VM_MAP, PAGE_KERNEL);

Is there something I'm missing on the previous scenario?

cheers,
A.
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