Re: Device model operation hypercall (DMOP, re qemu depriv)

["Jan Beulich" <JBeulich@suse.com>]

>>> On 13.09.16 at 12:37, <george.dunlap@citrix.com> wrote:
> On 12/09/16 15:32, Jan Beulich wrote:
>>>>> On 09.09.16 at 17:16, <Jennifer.Herbert@citrix.com> wrote:
>>> The following code illustrates this idea:
>>>
>>> typedef struct dm_op_buffer {
>>>      XEN_GUEST_HANDLE(void) h;
>>>      size_t len;
>>> } dm_op_buffer_t;
>> 
>> This implies that we'll lose all type safety on the handles passed, as
>> is also emphasized by the use of raw_copy_from_guest() in the code
>> outline further down.
> 
> If most of the time the hypercalls are made by calling libxc functions,
> and the libxc functions have types as arguments, then the end caller has
> the same type safety.  We'll have to be careful inside the individual
> libxc functions, but that should be fairly straightforward to do.  So
> the places where we need to take extra care should be very localized.

My main fear isn't so much to get it wrong the first time round, but
to break things down the road by not adjusting types in all needed
places at once (because the compiler doesn't tell the programmer).

Jan


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