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Date: Tue, 8 Mar 2011 19:00:27 +0000
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Subject: Re: [Qemu-devel] how to convert guest virtual address to host virtual
	address in QEMU?
From: Stefan Hajnoczi <stefanha@gmail.com>
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To: Gunasekaran Dharman <guna.spam@gmail.com>
Cc: qemu-devel@nongnu.org

On Tue, Mar 8, 2011 at 5:30 PM, Gunasekaran Dharman <guna.spam@gmail.com> wrote:
> From guest application, Iam passing some virtual addresses to QEMU through
> device I/O operation. Now I want to convert these guest virtual addresses to
> host virtual addresses so that I can perform some operation using them. In
> QEMU, is there any macro or function available to convert guest virtual
> address to host virtual address?
> My objective is to perform guest's memcpy operation in host so that it will
> be faster.

That's not really possible.  On architectures with a software-managed
TLB you don't know the layout of the virtual memory structures
(because they are defined in software and not standardized).

I suggest learning about and optimizing TCG instead of inventing a
memcpy device because it can benefit all code and does not require a
custom device and guest drivers.

Stefan