Re: [Qemu-devel] [PATCH v2] spapr: populate ibm,loc-code

From: Alexey Kardashevskiy <aik@ozlabs.ru>
To: David Gibson <david@gibson.dropbear.id.au>
Cc: Michael Roth <mdroth@linux.vnet.ibm.com>,
	qemu-ppc@nongnu.org, qemu-devel@nongnu.org,
	Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>,
	agraf@suse.de
Subject: Re: [Qemu-devel] [PATCH v2] spapr: populate ibm,loc-code
Date: Mon, 30 Mar 2015 14:08:17 +1100	[thread overview]
Message-ID: <5518BE21.6030702@ozlabs.ru> (raw)
In-Reply-To: <20150330022516.GC9908@voom.fritz.box>

On 03/30/2015 01:25 PM, David Gibson wrote:
> On Mon, Mar 30, 2015 at 01:18:01PM +1100, Alexey Kardashevskiy wrote:
>> On 03/27/2015 08:49 PM, Nikunj A Dadhania wrote:
>>> Each hardware instance has a platform unique location code.  The OF
>>> device tree that describes a part of a hardware entity must include
>>> the “ibm,loc-code” property with a value that represents the location
>>> code for that hardware entity.
>>>
>>> Introduce an hcall to populate ibm,loc-code.
>>> 1) PCI passthru devices need to identify with its own ibm,loc-code
>>>     available on the host.
>>> 2) Emulated devices encode as following: qemu_<name>:<slot>.<fn>
>>>
>>> Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
> [snip]
>>> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
>>> index af71e8b..95157ac 100644
>>> --- a/include/hw/ppc/spapr.h
>>> +++ b/include/hw/ppc/spapr.h
>>> @@ -310,7 +310,10 @@ typedef struct sPAPREnvironment {
>>>   #define KVMPPC_H_LOGICAL_MEMOP  (KVMPPC_HCALL_BASE + 0x1)
>>>   /* Client Architecture support */
>>>   #define KVMPPC_H_CAS            (KVMPPC_HCALL_BASE + 0x2)
>>> -#define KVMPPC_HCALL_MAX        KVMPPC_H_CAS
>>> +#define KVMPPC_H_RTAS_UPDATE    (KVMPPC_HCALL_BASE + 0x3)
>>> +#define KVMPPC_H_REPORT_MC_ERR  (KVMPPC_HCALL_BASE + 0x4)
>>> +#define KVMPPC_H_GET_LOC_CODE   (KVMPPC_HCALL_BASE + 0x5)
>>> +#define KVMPPC_HCALL_MAX        KVMPPC_H_GET_LOC_CODE
>>
>>
>> Please add only relevant codes. And what happened to patches adding
>> H_RTAS_UPDATE and H_REPORT_MC_ERR?
>>
>> Also (it is probably a very stupid question but still :) ), why are all
>> these callbacks - hypercalls, not RTAS calls? The hypercalls are numbered in
>> sPAPR and we kind of stealing numbers from that space while we are
>> allocating RTAS tokens ourselves and have more freedom.
>
> Also, I thought the plan was to remove PCI device enumeration from
> SLOF and move it to qemu (since we need to partially do that for
> hotplug).  That removes the need for the hcall entirely.

There was a strong opposition to PCI scan done by QEMU (although it was ok 
if PCI hotplug does some resource assignment in QEMU). Has this changed?

I added Michael in cc: and hope Alexander may enlighten us on this topic...

-- 
Alexey