Hi Mike,
The changes you proposed look nicer than what I have here.
I will get that coded and tested and re=submit.
Thanks.
-suresh
On 11/15/2015 11:53 PM, Michael Ellerman wrote:
> Hi Suresh,
>
> On Thu, 2015-29-10 at 23:40:45 UTC, "Suresh E. Warrier" wrote:
>> This function supports IPI message passing for real
>> mode callers.
>>
>> diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
>> index a53a130..8c07bfad 100644
>> --- a/arch/powerpc/kernel/smp.c
>> +++ b/arch/powerpc/kernel/smp.c
>> @@ -235,6 +238,33 @@ void smp_muxed_ipi_message_pass(int cpu, int msg)
>> smp_ops->cause_ipi(cpu, info->data);
>> }
>>
>> +#if defined(CONFIG_KVM_XICS) && defined(CONFIG_KVM_BOOK3S_HV_POSSIBLE)
>> +/*
>> + * Message passing code for real mode callers. It does not use the
>> + * smp_ops->cause_ipi function to cause an IPI, because those functions
>> + * access the MFFR through an ioremapped address.
>> + */
>> +void smp_muxed_ipi_rm_message_pass(int cpu, int msg)
>> +{
>> + struct cpu_messages *info = &per_cpu(ipi_message, cpu);
>> + char *message = (char *)&info->messages;
>> + unsigned long xics_phys;
>> +
>> + /*
>> + * Order previous accesses before accesses in the IPI handler.
>> + */
>> + smp_mb();
>> + message[msg] = 1;
>> +
>> + /*
>> + * cause_ipi functions are required to include a full barrier
>> + * before doing whatever causes the IPI.
>> + */
>> + xics_phys = paca[cpu].kvm_hstate.xics_phys;
>> + out_rm8((u8 *)(xics_phys + XICS_MFRR), IPI_PRIORITY);
>> +}
>> +#endif
>
>
> I'm not all that happy with this. This function does two things, one of which
> belongs in this file (setting message), and the other which definitely does
> not (the XICs part).
>
> I think the end result would be cleaner if we did something like:
>
> void smp_muxed_ipi_set_message(int cpu, int msg)
> {
> struct cpu_messages *info = &per_cpu(ipi_message, cpu);
> char *message = (char *)&info->messages;
> unsigned long xics_phys;
>
> /*
> * Order previous accesses before accesses in the IPI handler.
> */
> smp_mb();
> message[msg] = 1;
> }
>
> Which would be exported, and could also be used by
> smp_muxed_ipi_message_pass().
>
> Then in icp_rm_set_vcpu_irq(), you would do something like:
>
> if (hcore != -1) {
> hcpu = hcore << threads_shift;
> kvmppc_host_rm_ops_hv->rm_core[hcore].rm_data = vcpu;
> smp_muxed_ipi_set_message(hcpu, PPC_MSG_RM_HOST_ACTION);
> icp_native_cause_ipi_real_mode();
> }
>
> Where icp_native_cause_ipi_real_mode() is a new hook you define in
> icp_native.c
> which does the real mode write to MFRR.
>
> cheers
>
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