RE: [Xen-devel] [PATCH 4] MCA physical address check when calculate domain

["Liu, Jinsong" <jinsong.liu@xxxxxxxxx>]

Jan Beulich wrote:
>>>> On 10.05.11 at 08:38, "Liu, Jinsong" <jinsong.liu@xxxxxxxxx> wrote:
>> As for physical addr, the addr in MCi_ADDR reg may be linear add/
>> physical add/ setment offset. according to Intel SDM, the addr in
>> MCi_ADDR reg is physical addr only when: 1). MISCV bit of MCi_STATUS
>> set; 2). ADDRV bit of MCi_STATUS set;
>> 3). address mode of MCi_MISC (bit 6~8) = 010;
> 
> I realize this is what's being documented currently. Going back to the
> newest hard copy manual I still have (PentiumPro, which luckily is the
> first one where the banked implementation is described), there's no
> MCi_MISC (it's documented, but said to not be implemented on these
> old CPUs), and the description for the address reads "The address
> returned is either 32-bit virtual, 32-bit linear, or 36-bit
> physical". Now I certainly don't care much about PPro anymore, but I
> wonder when MCi_MISC was first implemented in the way your patch is
> using it. 
> 

Seems needn't care about when MCi_MISC first implemented. MCi_STATUS_MISCV 
check can make sure accessing MCi_MISC safely.

If really want to know MCi_MISC implemented at which processor, we can use 
cpuid DF_DM as clue. 
Different MCi_MISC implemented at different DF_DM processors (refer Intel SDM, 
Appendix B).
Currently there are 22 MCi_MISC (refer Table B-2), generally
MC0~4_MISC implement for all P6 processors;
MC5_MISC after 06_0F;
MC6_MISC after 06_1D;
...
MC21_MISC after 06_2E;

However, if want to check exactually how many MCi_MISC reg a processor has, it 
has to check 'count' field of IA32_MCG_CAP.
Take SNB processor (refer Table B-10) as example: It only support MC0~3_MISC 
openly (this does mean it has no other MCi_MISC, but means we can use 
MC0~3_MISC SAFELY).


> Further, the current manual also makes a distinction between
> "Physical Address" and "Memory Address", and additionally has
> a "Generic" type - all without further explanation.
> 
> Jan

Memory address is from the view of memory controller, say, channel number, as 
far as I understand. 
I don't know what 'Generic' means either.

Thanks,
Jinsong
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