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Re: [RFC PATCH 5/5] spapr: Allow up to 8 threads SMT configuration
From: |
Cédric Le Goater |
Subject: |
Re: [RFC PATCH 5/5] spapr: Allow up to 8 threads SMT configuration |
Date: |
Thu, 1 Jun 2023 09:20:36 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.10.0 |
On 5/31/23 03:23, Nicholas Piggin wrote:
TCG now supports multi-threaded configuration at least enough for
pseries to be functional enough to boot Linux.
This requires PIR and TIR be set, because that's how sibling thread
matching is done.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
hw/ppc/spapr.c | 4 ++--
hw/ppc/spapr_cpu_core.c | 7 +++++--
2 files changed, 7 insertions(+), 4 deletions(-)
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index dcb7f1c70a..11074cefea 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -2524,8 +2524,8 @@ static void spapr_set_vsmt_mode(SpaprMachineState *spapr,
Error **errp)
int ret;
unsigned int smp_threads = ms->smp.threads;
- if (!kvm_enabled() && (smp_threads > 1)) {
- error_setg(errp, "TCG cannot support more than 1 thread/core "
+ if (!kvm_enabled() && (smp_threads > 8)) {
+ error_setg(errp, "TCG cannot support more than 8 threads/core "
"on a pseries machine");
I think we should add test on the CPU also.
return;
}
diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
index 9b88dd549a..f35ee600f1 100644
--- a/hw/ppc/spapr_cpu_core.c
+++ b/hw/ppc/spapr_cpu_core.c
@@ -255,7 +255,7 @@ static void spapr_cpu_core_unrealize(DeviceState *dev)
}
static bool spapr_realize_vcpu(PowerPCCPU *cpu, SpaprMachineState *spapr,
- SpaprCpuCore *sc, Error **errp)
+ SpaprCpuCore *sc, int thread_nr, Error **errp)
thread_index may be ?
{
CPUPPCState *env = &cpu->env;
CPUState *cs = CPU(cpu);
@@ -267,6 +267,9 @@ static bool spapr_realize_vcpu(PowerPCCPU *cpu,
SpaprMachineState *spapr,
cpu_ppc_set_vhyp(cpu, PPC_VIRTUAL_HYPERVISOR(spapr));
kvmppc_set_papr(cpu);
so, spapr_create_vcpu() set cs->cpu_index :
cs->cpu_index = cc->core_id + i;
and spapr_realize_vcpu :
+ env->spr_cb[SPR_PIR].default_value = cs->cpu_index;
+ env->spr_cb[SPR_TIR].default_value = thread_nr;
+
it would be cleaner to do the SPR assignment in one place.
/* Set time-base frequency to 512 MHz. vhyp must be set first. */
cpu_ppc_tb_init(env, SPAPR_TIMEBASE_FREQ);
@@ -337,7 +340,7 @@ static void spapr_cpu_core_realize(DeviceState *dev, Error **errp)
for (i = 0; i < cc->nr_threads; i++) {
sc->threads[i] = spapr_create_vcpu(sc, i, errp);
if (!sc->threads[i] ||
- !spapr_realize_vcpu(sc->threads[i], spapr, sc, errp)) {
+ !spapr_realize_vcpu(sc->threads[i], spapr, sc, i, errp)) {
spapr_cpu_core_unrealize(dev);
return;
}
- Re: [RFC PATCH 5/5] spapr: Allow up to 8 threads SMT configuration,
Cédric Le Goater <=