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Re: [Xen-API] [Xen-users] xen physical addressïpaddrïand machine address (maddr)

On Sun, 2015-06-28 at 13:13 +0800, xinyue wrote:

please do not cross post.

You question seems to be xen-development related, so I have put the
other two to bcc.

>        I wan't to hash the kernel code segment of HVM DomU in Xen
> hypervisor, so I have to transilate the virtral address in VM to the
> virtral address in xen. Is there some easy ways ?

You need to first translate the guest virtual address to a guest
physical address and then to a machine address which you can then map in
to Xen.

I think you need paging_gva_to_gfn for the first step, then one of the
get_gfn* functions, then map_domain_page. I don't know if there is a
helper which will simplify all this.

>        I read the source code about memory in Xen and confuse the
> relationship between the paddr and maddr. How does HVM with EPT
> translate between them. Is paddr the same with virtral address in xen
> heap?

No. A paddr is a physical address, not a virtual one.

The latest xen.git contains a comment in xen/include/xen/mm.h which
describes the different types of memory.

To get a Xen virtual address for a domheap page you need to use
(un)map_domain_page on the underlying machine address (or struct
page_info *) to create a temporary mapping. For xenheap pages you can
use other mechanisms, but for an arbitrary guest page it is unlikely to
be from the xenheap.

> Thanks for any advices and with best regards!
> xinyue
> _______________________________________________
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> Xen-users@xxxxxxxxxxxxx
> http://lists.xen.org/xen-users

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