From mboxrd@z Thu Jan  1 00:00:00 1970
From: Lamia Youseff <lyouseff@cs.ucsb.edu>
Subject: Problem using alloc_vm_area()
Date: Wed, 22 Oct 2008 19:28:35 -0700
Message-ID: <48FFE153.4020706@cs.ucsb.edu>
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Return-path: <xen-devel-bounces@lists.xensource.com>
List-Unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xensource.com>
List-Help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-Subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
Sender: xen-devel-bounces@lists.xensource.com
Errors-To: xen-devel-bounces@lists.xensource.com
To: Xen-devel@lists.xensource.com
List-Id: xen-devel@lists.xenproject.org

Hi all,

I am having trouble mapping an area allocated by vmalloc_alloc_area to
user space. I would appreciate any help or hint on what i might be
missing in my implementation.

Inside my device_mmap, this is what i do.
I first allocate memory using
1. mem = alloc_vm_area( 1 * PAGE_SIZE );


then i get pfn using vmalloc_to_pfn,
2. pfn = vmalloc_to_pfn((struct vm_struct*)mem)->addr);

then, i try to map it using
3. ret = remap_pfn_range(vma, vma->start, pfn, PAGE_SIZE,
                                  PAGE_SHARED);

Although remap_pfn_range does not return an error, the DomU kernel
randomly crashes, or if it worked, it is not mapped to user-space
correctly. I need your advise on line 2 & 3, if possible. Please, let me
know if i can provide more information,

Thank you,
-- Lamia