Re: [Qemu-devel] [Qemu-ppc] [PATCH v2 3/4] target-ppc: Build error log

[Alexey Kardashevskiy <aik@au1.ibm.com>]

On 09/05/2014 06:28 PM, Aravinda Prasad wrote:
> 
> 
> On Friday 05 September 2014 01:34 PM, Alexander Graf wrote:
>>
>>
>> On 04.09.14 13:13, Aravinda Prasad wrote:
>>> Whenever there is a physical memory error due to bit
>>> flips, which cannot be corrected by hardware, the error
>>> is passed on to the kernel. If the memory address in
>>> error belongs to guest address space then guest kernel
>>> is responsible to take action. Hence the error is passed
>>> on to guest via KVM by invoking 0x200 NMI vector.
>>>
>>> However, guest OS, as per PAPR, expects an error log
>>> upon such error. This patch registers a new hcall
>>> which is issued from 0x200 interrupt vector and builds
>>> the error log, copies the error log to rtas space and
>>> passes the address of the error log to guest
>>>
>>> Enhancement to KVM to perform above functionality is
>>> already in upstream kernel.
>>>
>>> Signed-off-by: Aravinda Prasad <aravinda@linux.vnet.ibm.com>
>>> ---
>>>  hw/ppc/spapr_hcall.c   |  154 ++++++++++++++++++++++++++++++++++++++++++++++++
>>>  include/hw/ppc/spapr.h |    4 +
>>>  2 files changed, 157 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
>>> index 01650ba..c3aa448 100644
>>> --- a/hw/ppc/spapr_hcall.c
>>> +++ b/hw/ppc/spapr_hcall.c
>>> @@ -14,6 +14,88 @@ struct SPRSyncState {
>>>      target_ulong mask;
>>>  };
>>>  
>>> +/* Offset from rtas-base where error log is placed */
>>> +#define RTAS_ERROR_OFFSET       (TARGET_PAGE_SIZE)
>>
>> You can't assume this. Please compute the value at the same place you
>> compute the rtas-size.
> 
> sure
> 
> 
>>
>>> +
>>> +#define RTAS_ELOG_SEVERITY_SHIFT         0x5
>>> +#define RTAS_ELOG_DISPOSITION_SHIFT      0x3
>>> +#define RTAS_ELOG_INITIATOR_SHIFT        0x4
>>> +
>>> +/*
>>> + * Only required RTAS event severity, disposition, initiator
>>> + * target and type are copied from arch/powerpc/include/asm/rtas.h
>>> + */
>>> +
>>> +/* RTAS event severity */
>>> +#define RTAS_SEVERITY_ERROR_SYNC    0x3
>>> +
>>> +/* RTAS event disposition */
>>> +#define RTAS_DISP_NOT_RECOVERED     0x2
>>> +
>>> +/* RTAS event initiator */
>>> +#define RTAS_INITIATOR_MEMORY       0x4
>>> +
>>> +/* RTAS event target */
>>> +#define RTAS_TARGET_MEMORY          0x4
>>> +
>>> +/* RTAS event type */
>>> +#define RTAS_TYPE_ECC_UNCORR        0x09
>>> +
>>> +/*
>>> + * Currently KVM only passes on the uncorrected machine
>>> + * check memory error to guest. Other machine check errors
>>> + * such as SLB multi-hit and TLB multi-hit are recovered
>>> + * in KVM and are not passed on to guest.
>>> + *
>>> + * DSISR Bit for uncorrected machine check error. Based
>>> + * on arch/powerpc/include/asm/mce.h
>>
>> Please don't include Linux code. This file is GPLv2+ licensed and I
>> don't want to taint it as GPLv2 only just for the sake of mce.
> 
> Hmm.. ok.  In that case I should not copy rtas_error_log structure below
> from kernel source as well.


I double checked with Alex and since arch/powerpc/include/asm/mce.h is
GPL2+ and spapr_hcall.c does not have a license so it is what QEMU's
license is (which is also GPL2+), copying is fine here.



-- 
Alexey Kardashevskiy
IBM OzLabs, LTC Team

e-mail: aik@au1.ibm.com
notes: Alexey Kardashevskiy/Australia/IBM