Re: RFC: MCA/MCE concept

["Christoph Egger" <Christoph.Egger@amd.com>]

On Thursday 14 June 2007 13:59:12 Gavin Maltby wrote:
> On 06/06/07 10:28, Christoph Egger wrote:
> > On Monday 04 June 2007 18:16:56 Gavin Maltby wrote:
> >> In terms of the form of the error event data, the simplest but also
> >> the dumbest would be a binary structure passed from hypervisor
> >> to dom0:
> >
> > struct mca_error_data_ver1 {
> >  	uint8_t version;	/* structure version */
> >  	uint64_t mc_status;
> >  	uint64_t mc_addr;
> >  	uint64_t mc_misc;
> >  	uint16_t mc_chip;
> >  	uint16_t mc_core;
> >  	uint16_t mc_bank;
> >         uint16_t domid;
> >         uint16_t vcpu_id;
> >  	...
> > };
>
> Since there are multiple MCA detector banks, and more than
> one may have logged a valid error, we need to think about
> communicating all the bank error telemetry.  This should
> also allow for there being varying numbers of MCA banks in
> different proccessor types.  So something like
>
> struct {
> 	uint8_t version;
> 	uint8_t nbanks;
> 	uint16_t flags;
> 	uint16_t domid;
> 	uint16_t vcpud_id; /* if meaningful? */
> 	uint8_t chipid;
> 	uint8_t coreid;
> 	uint64_t mcg_status;
> 	struct {
> 		mc_status;
> 		mc_addr;
> 		mc_misc;
> 	} bank[1];
> };
>
> The bank array is actually sized as per nbanks.
>
> I've added mcg_status and flags.  The latter I'd like to use
> for indicators such as "this error data was artificially injected"
> etc.

Here is my proposal for a real exensible event structure:

#define MCA_TYPE_COMMON  0
#define MCA_TYPE_BANK         1
#define MCA_TYPE_ALLBANKS 2
...

#define MCA_COMMON     \
     size_t size;  /* size of this struct in bytes */
     uint32_t type; /* structure type */
     uint16_t domid;
     uint8_t chipid;
     uint8_t coreid;
     uint64_t mcg_status; /* global status */


The base structure:

struct mca_event {
     MCA_COMMON;
};


The specific structs:

struct mca_event_bank {
   MCA_COMMON;

   uint16_t vcpu_id;
   uint16_t mc_bank;
   uint64_t mc_status;
   uint64_t mc_addr;
   uint64_t mc_misc;
   uint32_t flags;
};

struct mca_event_allbanks {
   MCA_COMMON;

   uint16_t vcpud_id;
   uint8_t nbanks;
   uint32_t flags;
   struct {
 	uint64_t mc_status;
 	uint64_t mc_addr;
 	uint64_t mc_misc;
   } bank[1];
};

And you can have many more structs to support future features.

In the code you allocate the size of the struct you want to use:

     struct mca_event *mca = malloc(sizeof(struct mca_event_bank));
     mca->size = sizeof(struct mca_event_bank);
     mca->type = MCA_TYPE_BANK;

in this example you can cast from mca_event to mca_event_bank
and back whenever you like.
The generic code only needs to know struct mca_event.

Christoph


-- 
AMD Saxony, Dresden, Germany
Operating System Research Center

Legal Information:
AMD Saxony Limited Liability Company & Co. KG
Sitz (Geschäftsanschrift):
   Wilschdorfer Landstr. 101, 01109 Dresden, Deutschland
Registergericht Dresden: HRA 4896
vertretungsberechtigter Komplementär:
   AMD Saxony LLC (Sitz Wilmington, Delaware, USA)
Geschäftsführer der AMD Saxony LLC:
   Dr. Hans-R. Deppe, Thomas McCoy