[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [patch] "frame number" size in hypercall ABI
On Thu, 2006-04-20 at 17:18 +0100, Keir Fraser wrote: > 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. But those single values can't be passed around as longs in other areas, such as libxc. In libxc there is usually a path of xc_get_pfn_list() -> ... -> xc_map_foreign_page() (or whatever), and I need to make sure that the PFNs don't get truncated to 32 bits anywhere along that path. So I don't want to limit this patch to just *arrays* of PFNs. That means it would have to encompass all "frame numbers" in the Xen interface, including dom0_ops, memory_ops, start_info, shared_info... Is that a logical split for you? Are you waiting for this patch to be finalized before applying the GET/SET_HANDLE patch? -- Hollis Blanchard IBM Linux Technology Center _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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