Re: [Qemu-devel] [PATCH 1/5] target-ppc: Extend rtas-blob

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

On 09/01/2014 09:23 PM, Aravinda Prasad wrote:
> 
> 
> On Monday 01 September 2014 01:16 PM, Alexey Kardashevskiy wrote:
>> On 08/25/2014 11:45 PM, Aravinda Prasad wrote:
>>> Extend rtas-blob to accommodate error log. Error log
>>> structure is saved in rtas space upon a machine check
>>> exception.
>>>
>>> Signed-off-by: Aravinda Prasad <aravinda@linux.vnet.ibm.com>
>>> ---
>>>  hw/ppc/spapr.c                  |   13 ++++++++++---
>>>  hw/ppc/spapr_rtas.c             |    4 ++--
>>>  include/hw/ppc/spapr.h          |    2 +-
>>>  pc-bios/spapr-rtas/spapr-rtas.S |   12 ++++++++++++
>>>  4 files changed, 25 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
>>> index d01978f..1120988 100644
>>> --- a/hw/ppc/spapr.c
>>> +++ b/hw/ppc/spapr.c
>>> @@ -85,6 +85,12 @@
>>>  
>>>  #define HTAB_SIZE(spapr)        (1ULL << ((spapr)->htab_shift))
>>>  
>>> +/*
>>> + * The rtas-entry-offset should match the value specified in
>>> + * spapr-rtas.S
>>> + */
>>> +#define RTAS_ENTRY_OFFSET       0x1000
>>> +
>>>  typedef struct sPAPRMachineState sPAPRMachineState;
>>>  
>>>  #define TYPE_SPAPR_MACHINE      "spapr-machine"
>>> @@ -670,7 +676,8 @@ static int spapr_populate_memory(sPAPREnvironment *spapr, void *fdt)
>>>  static void spapr_finalize_fdt(sPAPREnvironment *spapr,
>>>                                 hwaddr fdt_addr,
>>>                                 hwaddr rtas_addr,
>>> -                               hwaddr rtas_size)
>>> +                               hwaddr rtas_size,
>>> +                               hwaddr rtas_entry)
>>>  {
>>>      int ret, i;
>>>      size_t cb = 0;
>>> @@ -705,7 +712,7 @@ static void spapr_finalize_fdt(sPAPREnvironment *spapr,
>>>      }
>>>  
>>>      /* RTAS */
>>> -    ret = spapr_rtas_device_tree_setup(fdt, rtas_addr, rtas_size);
>>> +    ret = spapr_rtas_device_tree_setup(fdt, rtas_addr, rtas_size, rtas_entry);
>>>      if (ret < 0) {
>>>          fprintf(stderr, "Couldn't set up RTAS device tree properties\n");
>>>      }
>>> @@ -808,7 +815,7 @@ static void ppc_spapr_reset(void)
>>>  
>>>      /* Load the fdt */
>>>      spapr_finalize_fdt(spapr, spapr->fdt_addr, spapr->rtas_addr,
>>> -                       spapr->rtas_size);
>>> +                       spapr->rtas_size, spapr->rtas_addr + RTAS_ENTRY_OFFSET);
>>>  
>>>      /* Set up the entry state */
>>>      first_ppc_cpu = POWERPC_CPU(first_cpu);
>>> diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
>>> index 9ba1ba6..02ddbf9 100644
>>> --- a/hw/ppc/spapr_rtas.c
>>> +++ b/hw/ppc/spapr_rtas.c
>>> @@ -328,7 +328,7 @@ void spapr_rtas_register(int token, const char *name, spapr_rtas_fn fn)
>>>  }
>>>  
>>>  int spapr_rtas_device_tree_setup(void *fdt, hwaddr rtas_addr,
>>> -                                 hwaddr rtas_size)
>>> +                                 hwaddr rtas_size, hwaddr rtas_entry)
>>>  {
>>>      int ret;
>>>      int i;
>>> @@ -349,7 +349,7 @@ int spapr_rtas_device_tree_setup(void *fdt, hwaddr rtas_addr,
>>>      }
>>>  
>>>      ret = qemu_fdt_setprop_cell(fdt, "/rtas", "linux,rtas-entry",
>>> -                                rtas_addr);
>>> +                                rtas_entry);
>>>      if (ret < 0) {
>>>          fprintf(stderr, "Couldn't add linux,rtas-entry property: %s\n",
>>>                  fdt_strerror(ret));
>>> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
>>> index bbba51a..dedfa67 100644
>>> --- a/include/hw/ppc/spapr.h
>>> +++ b/include/hw/ppc/spapr.h
>>> @@ -436,7 +436,7 @@ target_ulong spapr_rtas_call(PowerPCCPU *cpu, sPAPREnvironment *spapr,
>>>                               uint32_t token, uint32_t nargs, target_ulong args,
>>>                               uint32_t nret, target_ulong rets);
>>>  int spapr_rtas_device_tree_setup(void *fdt, hwaddr rtas_addr,
>>> -                                 hwaddr rtas_size);
>>> +                                 hwaddr rtas_size, hwaddr rtas_entry);
>>>  
>>>  #define SPAPR_TCE_PAGE_SHIFT   12
>>>  #define SPAPR_TCE_PAGE_SIZE    (1ULL << SPAPR_TCE_PAGE_SHIFT)
>>> diff --git a/pc-bios/spapr-rtas/spapr-rtas.S b/pc-bios/spapr-rtas/spapr-rtas.S
>>> index 903bec2..8c9b17e 100644
>>> --- a/pc-bios/spapr-rtas/spapr-rtas.S
>>> +++ b/pc-bios/spapr-rtas/spapr-rtas.S
>>> @@ -30,6 +30,18 @@
>>>  
>>>  .globl	_start
>>>  _start:
>>> +	/*
>>> +	 * Reserve space for error log in RTAS blob.
>>> +	 *
>>> +	 * Either we can reserve initial bytes for error log followed by
>>> +	 * rtas-entry or space can be reserved after rtas-entry. I prefer
>>> +	 * former, as we already have rtas-base and rtas-entry (currently
>>> +	 * both pointing to rtas-base) defined in qemu and we can update
>>> +	 * rtas-entry to point to an offset from rtas-base. This avoids
>>> +	 * unnecessary definition of rtas-error-offset while keeping
>>> +	 * rtas-entry redundant.
>>> +	 */
>>> +	. = 0x1000
>>
>>
>> Why not this (and not changing spapr-rtas.S)?
>>
>> --- a/hw/ppc/spapr.c
>> +++ b/hw/ppc/spapr.c
>> @@ -875,7 +875,8 @@ static void ppc_spapr_reset(void)
>>                         spapr->rtas_size);
>>
>>      /* Copy RTAS over */
>> -    cpu_physical_memory_write(spapr->rtas_addr, spapr->rtas_blob,
>> +    cpu_physical_memory_write(spapr->rtas_addr + RTAS_ENTRY_OFFSET,
>> +                              spapr->rtas_blob,
>>                                spapr->rtas_size);
> 
> This is possible, however requires suitable adjustment to make sure
> spapr->rtas_addr has enough space allocated.


How is adding RTAS_ENTRY_OFFSET not enough to make sure that is has enough
space? QEMU copies RTAS to guest memory, QEMU makes up rtas_addr/entry
properties.


> 
>>
>>
>>
>>
>>>  	mr	4,3
>>>  	lis	3,KVMPPC_H_RTAS@h
>>>  	ori	3,3,KVMPPC_H_RTAS@l
>>>
>>
>>
> 


-- 
Alexey Kardashevskiy
IBM OzLabs, LTC Team

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