Re: [Qemu-devel] [PATCH v18 1/2] sPAPR: Implement EEH RTAS calls

[Gavin Shan <gwshan@linux.vnet.ibm.com>]

On Mon, Feb 16, 2015 at 04:32:09PM +1100, Gavin Shan wrote:
>On Mon, Feb 16, 2015 at 12:52:48PM +1100, David Gibson wrote:
>>On Mon, Feb 16, 2015 at 10:16:01AM +1100, Gavin Shan wrote:
>>> The emulation for EEH RTAS requests from guest isn't covered
>>> by QEMU yet and the patch implements them.
>>> 
>>> The patch defines constants used by EEH RTAS calls and adds
>>> callbacks sPAPRPHBClass::{eeh_set_option, eeh_get_state, eeh_reset,
>>> eeh_configure}, which are going to be used as follows:
>>> 
>>>   * RTAS calls are received in spapr_pci.c, sanity check is done
>>>     there.
>>>   * RTAS handlers handle what they can. If there is something it
>>>     cannot handle and the corresponding sPAPRPHBClass callback is
>>>     defined, it is called.
>>>   * Those callbacks are only implemented for VFIO now. They do ioctl()
>>>     to the IOMMU container fd to complete the calls. Error codes from
>>>     that ioctl() are transferred back to the guest.
>>> 
>>> [aik: defined RTAS tokens for EEH RTAS calls]
>>> Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
>>> ---
>>>  hw/ppc/spapr_pci.c          | 281 ++++++++++++++++++++++++++++++++++++++++++++
>>>  include/hw/pci-host/spapr.h |   4 +
>>>  include/hw/ppc/spapr.h      |  43 ++++++-
>>>  3 files changed, 326 insertions(+), 2 deletions(-)
>>> 
>>> diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
>>> index cebdeb3..29b071d 100644
>>> --- a/hw/ppc/spapr_pci.c
>>> +++ b/hw/ppc/spapr_pci.c
>>> @@ -406,6 +406,268 @@ static void rtas_ibm_query_interrupt_source_number(PowerPCCPU *cpu,
>>>      rtas_st(rets, 2, 1);/* 0 == level; 1 == edge */
>>>  }
>>>  
>>> +static void rtas_ibm_set_eeh_option(PowerPCCPU *cpu,
>>> +                                    sPAPREnvironment *spapr,
>>> +                                    uint32_t token, uint32_t nargs,
>>> +                                    target_ulong args, uint32_t nret,
>>> +                                    target_ulong rets)
>>> +{
>>> +    sPAPRPHBState *sphb;
>>> +    sPAPRPHBClass *spc;
>>> +    uint32_t addr, option;
>>> +    uint64_t buid;
>>> +    int ret;
>>> +
>>> +    if ((nargs != 4) || (nret != 1)) {
>>> +        goto param_error_exit;
>>> +    }
>>> +
>>> +    buid = ((uint64_t)rtas_ld(args, 1) << 32) | rtas_ld(args, 2);
>>> +    addr = rtas_ld(args, 0);
>>> +    option = rtas_ld(args, 3);
>>> +
>>> +    sphb = find_phb(spapr, buid);
>>> +    if (!sphb) {
>>> +        goto param_error_exit;
>>> +    }
>>> +
>>> +    spc = SPAPR_PCI_HOST_BRIDGE_GET_CLASS(sphb);
>>> +    if (!spc->eeh_set_option) {
>>> +        goto param_error_exit;
>>> +    }
>>> +
>>> +    /*
>>> +     * The EEH functionality is enabled on basis of PCI device,
>>> +     * instead of PE. We need check the validity of the PCI
>>> +     * device address.
>>> +     */
>>> +    if (option == RTAS_EEH_ENABLE &&
>>> +        !find_dev(spapr, buid, addr)) {
>>> +        goto param_error_exit;
>>> +    }
>>
>>You're still breaking your layering by doing checks dependent on the
>>specific option both here and in the callback.
>>
>>What I meant by my comments on the previous version was that this
>>find_dev() test should also move into the eeh_set_option callback.
>>Obviously that means adding addr into the parameters - but surely if
>>the addr has any meaning whatsoever, it must be at least potentially
>>needed by the callback anyway.
>>
>
>Ok. Either simply dropping the check here, or moving find_dev() to
>sPAPRPHBClass::eeh_set_option() as you suggested. However, there're more
>things needed for sPAPRPHBClass::eeh_set_option() to do the check as follows.
>David, could you help to confirm which way you prefer?
>
>- Rename find_dev() to spapr_find_pci_dev() and make it public. It will be
>  called in spapr_pci_vfio.c
>- Add one field sPAPRPHBState::spapr to reference the associated sPAPREnvironment,
>  which is required by spapr_find_pci_dev(). Otherwise, we have to pass sPAPREnvironment
>  to sPAPRPHBClass::eeh_set_option().
>

Ping, David? If you don't object, I'll drop the check simply in next revision.
Note that I dropped public find_phb()/find_dev() in v15 and I don't want change
the code back.

Thanks,
Gavin

>>Apart from that,
>>
>>Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
>>
>>-- 
>>David Gibson			| I'll have my music baroque, and my code
>>david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
>>				| _way_ _around_!
>>http://www.ozlabs.org/~dgibson
>
>