On 04/24/2015 03:19 AM, Jan Beulich wrote:
On 24.04.15 at 00:20, <boris.ostrov...@oracle.com> wrote:
On 04/21/2015 03:01 AM, Jan Beulich wrote:
+ ((++dev_cnt > 0x3f) && hypercall_preempt_check()) )
+ break;
+ }
+
+ if ( (!ret || (ret == -ENODEV)) &&
+ __copy_field_to_guest(u_sysctl, op, u.pcitopoinfo.first_dev) )
+ ret = -EFAULT;
+ }
+ break;
+#endif
With the continuation-less model now used I don't think it makes
sense to have first_dev and num_devs - for re-invocation all the
caller needs to do is increment the buffer pointer suitably. I.e.
you can get away with just a count of devices afaict.
This would require walking xc_hypercall_buffer_t->hbuf. Would something like
set_xen_guest_handle_raw(sysctl..., (void *)HYPERCALL_BUFFER_AS_ARG(foo)
+ offset)
be acceptable? I don't think I see anything better.
I thought of adding set_xen_guest_handle_offset() that would look
similar to set_xen_guest_handle() but then I felt that having this in
API may not be a good idea since xc_hypercall_buffer_t->hbuf would end
up pointing to memory that is not allocated for full
xc_hypercall_buffer_t->sz.
There ought to be a way to create a guest handle from other than
the start of an allocated hypercall buffer, but that's really more a
question for the tool stack folks.
Yes, this was question for toolstack people.
(And my second paragraph was not stated correctly, now that I re-read
it. I meant to say that my understanding is that API is expected to make
all safety checks on buffers and with set_xen_guest_handle_offset() that
I was picturing in my head we could pass in pretty much any pointer. I
suppose we could check 'hbuf+offset < sz')
-boris
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