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Re: [Xen-devel] [patch] "frame number" size in hypercall ABI

On 20 Apr 2006, at 17:09, Hollis Blanchard wrote:

So are you saying you want the patch to include Linux kernel changes?
But not Xen changes (e.g. shadow.h) other than right at the interface?

Yes, at least where Linux is handling arrays that will get passed to a hypercall or the array could end up the wrong size! Of course it really doesn't matter for singleton values so they can safely be left as-is.

The same goes for Xen too, but I believe the arrays are only handled in the very hypercall functions that receive them. For example, many functions in common/memory.c will need to read/write values to from a xen_pfn_t, but these singleton values can then be passed around inside Xen as longs.

I needed to change all users in libxc because they all index into
page_array[] as unsigned long. Theoretically speaking you could have the same problem within Linux and Xen as well. The word "unpacking" suggests
a conversion step, which is something I'm not introducing here.

The arrays aren't passed around inside Xen (I'm pretty sure). As I say above, we read/write one-by-one.

 -- Keir

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