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From: Dan Magenheimer <dan.magenheimer@oracle.com>
To: Kaustubh Kabra <kaustubhwise@gmail.com>, xen-devel@lists.xensource.com
Cc: vasani.ashwin@gmail.com, keir@xen.org, Tim.Deegan@citrix.com
Subject: RE: Doubt regarding virtual memory mapping from hypervisor to a domain
Date: Mon, 31 Jan 2011 07:36:40 -0800 (PST)	[thread overview]
Message-ID: <7270db8c-d71a-4ab7-84fb-02ee256b44b7@default> (raw)
In-Reply-To: <AANLkTim1TzbX7mEXGYr3kBdY+E-4Y-8eNAYjnT3dWeYe@mail.gmail.com>

> From: Kaustubh Kabra [mailto:kaustubhwise@gmail.com]
> I have allocated few order=9 pages in Xen memory space using
> alloc_domheap_pages(NULL,9,0) during boot time just before domain is
> created (dom0 = domain_create(0, DOMCRF_s3_integrity, DOM0_SSIDREF) in
> xen/arch/x86/setup.c).
> 
> I got the following virtual addresses in xen log message-
> (XEN) a2k2: Virt_addr:ffff83011cc00000   MFN:11cc00
> (XEN) a2k2: Virt_addr:ffff83011ca00000   MFN:11ca00
> (XEN) a2k2: Virt_addr:ffff83011c800000   MFN:11c800
> (XEN) a2k2: Virt_addr:ffff83011c600000   MFN:11c600
> (XEN) a2k2: Virt_addr:ffff83011c400000   MFN:11c400
> (XEN) a2k2: Virt_addr:ffff83011c200000   MFN:11c200
> (XEN) a2k2: Virt_addr:ffff83011c000000   MFN:11c000
> (XEN) a2k2: Virt_addr:ffff83011be00000   MFN:11be00
> 
> As per config.h file Xen memory map,the virtual mapping shows that the
> memory is  allocated in
> 1:1 direct mapping of all physical memory .Can anyone elaborate
> regarding this mapping ?

It's not clear what you are asking.  Can you be more precise?
 
> Now can I allocate this mapped memory reserved by Xen hypervisor to
> any domain through any existing or my new hypercall?

Again, it's not clear what you are asking.  If you are
asking if the guest can map the order=9 page into its
memory space, I think the answer is no.  If you are
asking if Xen can use the memory on behalf of a
domain, for example to copy data from the domain into
Xen (like tmem does), I think the answer is yes.

  reply	other threads:[~2011-01-31 15:36 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-01-28 19:23 Doubt regarding virtual memory mapping from hypervisor to a domain Kaustubh Kabra
2011-01-31 15:36 ` Dan Magenheimer [this message]
2011-02-10 13:26   ` Kaustubh Kabra
2011-02-10 15:13     ` Konrad Rzeszutek Wilk

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