A Man Without A Country Daniel P. Berrange wrote:
I've been doing some testing with current xen-unstable (ie what will very shortly be 3.0.5) and came across a whole bunch of things which needed fixing - some expected, others not expected. The attached patch addresses the following issues:
As a general question about policy, are we going to support every rev of the HV interface? If Xen change the interface again before 3.0.5 will we support this "pre-3.0.5" and the final interface?
- Many of the hypercalls have their structs changed so that int64_t or 'foo *' members are always 64-bit aligned even on 32-bit platforms. This is part of the work to allow 32-bit Dom0/DomU to work on 64-bithypervisor.For the int64_t types I had to annotate with __attribute__((aligned(8))). This did not work for pointer data types, so I for those I had to do a more complex hack with union { foo *v; int64_t pad __attribute__((aligned(8))) }
What is the problem here? I did some tests and it seems to work just fine:
/* Test alignment of pointers.
* Richard Jones <rjones~at~redhat~dot~com>
*/
#include <stdio.h>
#undef offsetof
#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
struct s {
char c;
//int v;
//int v __attribute__((aligned(16)));
int *v __attribute__((aligned(16)));
//struct s *v __attribute__((aligned(16)));
};
int
main ()
{
printf ("offset = %d\n", offsetof (struct s, v));
return 0;
}
$ gcc -Wall -Werror align.c -o align
$ ./align
offset = 16
$ arch
i686
$ gcc --version
gcc (GCC) 3.3.5 (Debian 1:3.3.5-13)
Copyright (C) 2003 Free Software Foundation, Inc. [etc]
- The unified Xen driver broke the GetVCPUs method - it was mistakenly
checking for return value == 0, instead of > 0. Trivial fix.
Ooops.
I've tested all this on a 32-bit Dom0 running on 32-bit HV, and 64-bit HV, but not tested a 64-bit Dom0 on 64-bit HV. I'm pretty sure it'll work,but if anyone is runnning 64-on-64 please test this patch.
I don't have 3.0.5 to test here, but I can possibly test this on Monday. In the meantime I eyeballed the patch and from what I can tell it seems fine.
Rich. -- Emerging Technologies, Red Hat http://et.redhat.com/~rjones/ 64 Baker Street, London, W1U 7DF Mobile: +44 7866 314 421 Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 Directors: Michael Cunningham (USA), Charlie Peters (USA) and David Owens (Ireland)
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