Re: [PATCH v2 4/4] x86: adjustments to guest handle treatment

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Tue, Apr 21, 2020 at 11:13:23AM +0200, Jan Beulich wrote:
> First of all avoid excessive conversions. copy_{from,to}_guest(), for
> example, work fine with all of XEN_GUEST_HANDLE{,_64,_PARAM}().

I'm not sure I understand the difference between those two, as they
are both placeholders for linear guest addresses?

AFAICT XEN_GUEST_HANDLE should be used for guest pointers inside of an
hypercall struct, while XEN_GUEST_HANDLE_PARAM is for guest pointers
as hypercall arguments. But those are both just guest pointers,
whether they are a parameter to the hypercall or a field in a
struct, and hence could use the same type?

I assume there's some reason for not doing so, and I see the comment
about other arches, but again a linear guest address is just that in
all arches, regardless of it's placement.

Sorry, this is likely tangential to your patch.

Thanks, Roger.