Re: [PATCH] fix c/s 18938

["Jan Beulich" <jbeulich@novell.com>]

>>> Christoph Egger <Christoph.Egger@amd.com> 27.03.09 17:49 >>>
>On Friday 27 March 2009 17:34:07 Jan Beulich wrote:
>> -     * Currently Intel extended MSR (32/64) including all gp registers
>> -     * and E(R)DI, E(R)BP, E(R)SP, E(R)FLAGS, E(R)IP, E(R)MISC, only 10
>> -     * of them might be useful. So expend this array to 10.
>> -    */
>> -    struct mcinfo_msr mc_msr[10];
>> +     * Currently Intel extended MSR (32/64) include all gp registers
>> +     * and E(R)FLAGS, E(R)IP, E(R)MISC, up to 11/19 of them might be
>> +     * useful at present. So expand this array to 16/32 to leave room.
>> +     */
>> +    struct mcinfo_msr mc_msr[sizeof(void *) * 4];
>
>Please make this a fixed sized array. There are users like Oracle who run
>a 32bit PAE Dom0 on a 64bit Xen ...

And you expect a 32-bit kernel to be able to make sense of the MSRs
corresponding to 64-bit-only registers?

But you remind me that I failed to handle the difference in size of that
array for 32-on-64 - I really need to check why the structure layout
checking logic didn't catch the difference in size. Oh, right, sizeof(void *)
needs special treatment (and I really don#t want to sue sizeof(long)
here due to the implied dependency on the OS ABI).

Jan