Re: [Qemu-devel] [PATCH v5 1/6] ppc: spapr: Register and handle HCALL to receive updated RTAS region

[Aravinda Prasad <aravinda@linux.vnet.ibm.com>]

On Friday 29 September 2017 11:47 AM, David Gibson wrote:
> On Thu, Sep 28, 2017 at 04:07:38PM +0530, Aravinda Prasad wrote:
>> Receive updates from SLOF about the updated rtas-base.
>> A separate patch for SLOF [1] (commit f9a60de3) adds
>> functionality to invoke a private HCALL whenever OS
>> issues instantiate-rtas with a new rtas-base.
>>
>> This is required as QEMU needs to know the updated rtas-base
>> as it allocates error reporting structure in RTAS space upon
>> a machine check exception.
>>
>> [1] https://lists.ozlabs.org/pipermail/linuxppc-dev/2014-August/120386.html
>>
>> Signed-off-by: Aravinda Prasad <aravinda@linux.vnet.ibm.com>
>> Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
> 
> Ao I acked this earlier, but I've now realized there might be some
> connection between this and discussions taking place elsewhere about
> qemu not knowing what SLOF does with the device tree.
> 
> At what point will SLOF call the UPDATE_RTAS hcall?  I'm guessing at
> the time of instantiate-rtas, is that right?
> 
> Does SLOF put the RTAS blob address in its internal device tree, or
> does it only pass it to the guest via the return parameters from
> instantiate-rtas?

The new set of patches posted by Alexey exports RTAS address via device
tree to QEMU. Once this is in, I will remove this patch and rebase the
rest of the patches.

Regards,
Aravinda

> 
>> ---
>>  hw/ppc/spapr.c         |   11 +++++++++++
>>  hw/ppc/spapr_hcall.c   |    8 ++++++++
>>  include/hw/ppc/spapr.h |    4 +++-
>>  3 files changed, 22 insertions(+), 1 deletion(-)
>>
>> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
>> index ff87f15..5deae30 100644
>> --- a/hw/ppc/spapr.c
>> +++ b/hw/ppc/spapr.c
>> @@ -1675,6 +1675,16 @@ static const VMStateDescription vmstate_spapr_patb_entry = {
>>      },
>>  };
>>  
>> +static const VMStateDescription vmstate_spapr_rtas_addr = {
>> +    .name = "spapr_rtas_addr",
>> +    .version_id = 1,
>> +    .minimum_version_id = 1,
>> +    .fields = (VMStateField[]) {
>> +        VMSTATE_UINT64(rtas_addr, sPAPRMachineState),
>> +        VMSTATE_END_OF_LIST()
>> +    },
>> +};
>> +
>>  static const VMStateDescription vmstate_spapr = {
>>      .name = "spapr",
>>      .version_id = 3,
>> @@ -1694,6 +1704,7 @@ static const VMStateDescription vmstate_spapr = {
>>          &vmstate_spapr_ov5_cas,
>>          &vmstate_spapr_patb_entry,
>>          &vmstate_spapr_pending_events,
>> +        &vmstate_spapr_rtas_addr,
>>          NULL
>>      }
>>  };
>> diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
>> index 8d72bb7..c15a93c 100644
>> --- a/hw/ppc/spapr_hcall.c
>> +++ b/hw/ppc/spapr_hcall.c
>> @@ -1088,6 +1088,13 @@ static target_ulong h_rtas(PowerPCCPU *cpu, sPAPRMachineState *spapr,
>>                             nret, rtas_r3 + 12 + 4*nargs);
>>  }
>>  
>> +static target_ulong h_rtas_update(PowerPCCPU *cpu, sPAPRMachineState *spapr,
>> +                                  target_ulong opcode, target_ulong *args)
>> +{
>> +    spapr->rtas_addr = args[0];
>> +    return 0;
>> +}
>> +
>>  static target_ulong h_logical_load(PowerPCCPU *cpu, sPAPRMachineState *spapr,
>>                                     target_ulong opcode, target_ulong *args)
>>  {
>> @@ -1750,6 +1757,7 @@ static void hypercall_register_types(void)
>>  
>>      /* qemu/KVM-PPC specific hcalls */
>>      spapr_register_hypercall(KVMPPC_H_RTAS, h_rtas);
>> +    spapr_register_hypercall(KVMPPC_H_RTAS_UPDATE, h_rtas_update);
>>  
>>      /* ibm,client-architecture-support support */
>>      spapr_register_hypercall(KVMPPC_H_CAS, h_client_architecture_support);
>> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
>> index c1b365f..b395aa7 100644
>> --- a/include/hw/ppc/spapr.h
>> +++ b/include/hw/ppc/spapr.h
>> @@ -90,6 +90,7 @@ struct sPAPRMachineState {
>>  
>>      hwaddr rma_size;
>>      int vrma_adjust;
>> +    hwaddr rtas_addr;
>>      ssize_t rtas_size;
>>      void *rtas_blob;
>>      long kernel_size;
>> @@ -400,7 +401,8 @@ struct sPAPRMachineState {
>>  #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_HCALL_MAX        KVMPPC_H_RTAS_UPDATE
>>  
>>  typedef struct sPAPRDeviceTreeUpdateHeader {
>>      uint32_t version_id;
>>
> 

-- 
Regards,
Aravinda