On Tue, Aug 27, 2019 at 02:57:51PM +1000, Suraj Jitindar Singh wrote: > The ibm,get_system_parameter rtas call is used by the guest to retrieve > data relating to certain parameters of the system. The SPLPAR > characteristics option (token 20) is used to determine characteristics of > the environment in which the lpar will run. > > It may be useful for a guest to know the number of physical host threads > present on the underlying system where it is being run. Add the > characteristic "HostThrs" to the SPLPAR Characteristics > ibm,get_system_parameter rtas call to expose this information to a > guest. Add a n_host_threads property to the processor class which is > then used to retrieve this information and define it for POWER8 and > POWER9. Other processors will default to 0 and the charateristic won't > be added. > > Signed-off-by: Suraj Jitindar Singh <sjitindarsi...@gmail.com>
Applied, thanks.
>
> ---
>
> V1 -> V2:
> - Take into account that the core may be operating in split core mode
> meaning a single core may be split into multiple subcores.
> V2 -> V3:
> - Add curly braces for single line if statements
> V3 -> V4;
> - Add a host threads property to the processor class and use this to
> derive the information rather than the device tree.
> ---
> hw/ppc/spapr_rtas.c | 15 +++++++++++++++
> target/ppc/cpu-qom.h | 1 +
> target/ppc/translate_init.inc.c | 2 ++
> 3 files changed, 18 insertions(+)
>
> diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
> index 526b489297..bee3835214 100644
> --- a/hw/ppc/spapr_rtas.c
> +++ b/hw/ppc/spapr_rtas.c
> @@ -266,6 +266,7 @@ static void rtas_ibm_get_system_parameter(PowerPCCPU *cpu,
> target_ulong args,
> uint32_t nret, target_ulong rets)
> {
> + PowerPCCPUClass *pcc = POWERPC_CPU_GET_CLASS(cpu);
> MachineState *ms = MACHINE(qdev_get_machine());
> unsigned int max_cpus = ms->smp.max_cpus;
> target_ulong parameter = rtas_ld(args, 0);
> @@ -283,6 +284,20 @@ static void rtas_ibm_get_system_parameter(PowerPCCPU
> *cpu,
> current_machine->ram_size / MiB,
> ms->smp.cpus,
> max_cpus);
> + if (pcc->n_host_threads > 0) {
> + char *hostthr_val, *old = param_val;
> +
> + /*
> + * Add HostThrs property. This property is not present in PAPR
> but
> + * is expected by some guests to communicate the number of
> physical
> + * host threads per core on the system so that they can scale
> + * information which varies based on the thread configuration.
> + */
> + hostthr_val = g_strdup_printf(",HostThrs=%d",
> pcc->n_host_threads);
> + param_val = g_strconcat(param_val, hostthr_val, NULL);
> + g_free(hostthr_val);
> + g_free(old);
> + }
> ret = sysparm_st(buffer, length, param_val, strlen(param_val) + 1);
> g_free(param_val);
> break;
> diff --git a/target/ppc/cpu-qom.h b/target/ppc/cpu-qom.h
> index 7ffdb0a706..e499575dc8 100644
> --- a/target/ppc/cpu-qom.h
> +++ b/target/ppc/cpu-qom.h
> @@ -191,6 +191,7 @@ typedef struct PowerPCCPUClass {
> const PPCHash64Options *hash64_opts;
> struct ppc_radix_page_info *radix_page_info;
> uint32_t lrg_decr_bits;
> + int n_host_threads;
> void (*init_proc)(CPUPPCState *env);
> int (*check_pow)(CPUPPCState *env);
> int (*handle_mmu_fault)(PowerPCCPU *cpu, vaddr eaddr, int rwx, int
> mmu_idx);
> diff --git a/target/ppc/translate_init.inc.c b/target/ppc/translate_init.inc.c
> index 4a21ed7289..41f77b7ef8 100644
> --- a/target/ppc/translate_init.inc.c
> +++ b/target/ppc/translate_init.inc.c
> @@ -8770,6 +8770,7 @@ POWERPC_FAMILY(POWER8)(ObjectClass *oc, void *data)
> pcc->handle_mmu_fault = ppc_hash64_handle_mmu_fault;
> pcc->hash64_opts = &ppc_hash64_opts_POWER7;
> pcc->lrg_decr_bits = 32;
> + pcc->n_host_threads = 8;
> #endif
> pcc->excp_model = POWERPC_EXCP_POWER8;
> pcc->bus_model = PPC_FLAGS_INPUT_POWER7;
> @@ -8981,6 +8982,7 @@ POWERPC_FAMILY(POWER9)(ObjectClass *oc, void *data)
> pcc->hash64_opts = &ppc_hash64_opts_POWER7;
> pcc->radix_page_info = &POWER9_radix_page_info;
> pcc->lrg_decr_bits = 56;
> + pcc->n_host_threads = 4;
> #endif
> pcc->excp_model = POWERPC_EXCP_POWER9;
> pcc->bus_model = PPC_FLAGS_INPUT_POWER9;
--
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
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