Re: [Xen-devel] [PATCH v2 5/5] xen: replace XEN_GUEST_HANDLE with XEN_GUEST_HANDLE_PARAM when appropriate

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Mon, 13 Aug 2012, Jan Beulich wrote:
> >>> On 13.08.12 at 13:24, Stefano Stabellini 
> >>> <stefano.stabellini@xxxxxxxxxxxxx> wrote:
> > On the other hand if you mean casting a XEN_GUEST_HANDLE_PARAM into a
> > XEN_GUEST_HANDLE to pass it to other internal functions, I don't think
> > there is any point in that because the other internal functions should
> > also have XEN_GUEST_HANDLE_PARAMs as parameters.
> 
> So you obviously need a cast from "normal" to _PARAM (so that
> you can pass embedded fields to functions).

In practice embedded fields are in guest memory, so the first thing Xen
does is calling copy_from_guest and work with the struct pointer
directly from that point on.

However I do see how a function like that might make the distinction
between XEN_GUEST_HANDLE and XEN_GUEST_HANDLE_PARAMs clearer, so I'll
add one.

The implementation is going to identical to guest_handle_cast though.

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