[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

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

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.



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.