From 6393b29966fce3c0e47746a9646ae439e7fd0728 Mon Sep 17 00:00:00 2001 From: Pierre Morel Date: Thu, 3 Nov 2022 18:01:41 +0100 Subject: [PATCH] s390x/cpu topology: add max_threads machine class attribute The S390 CPU topology accepts the smp.threads argument while in reality it does not effectively allow multthreading. Let's keep this behavior for machines older than 7.2 and refuse to use threads in newer machines until multithreading is really exposed to the guest by the machine. Signed-off-by: Pierre Morel Message-Id: <20221103170150.20789-3-pmorel@linux.ibm.com> [thuth: Small fixes to the commit description] Signed-off-by: Thomas Huth --- hw/s390x/s390-virtio-ccw.c | 11 +++++++++++ include/hw/s390x/s390-virtio-ccw.h | 1 + 2 files changed, 12 insertions(+) diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c index 196773c833..560ddbb6fb 100644 --- a/hw/s390x/s390-virtio-ccw.c +++ b/hw/s390x/s390-virtio-ccw.c @@ -85,8 +85,15 @@ out: static void s390_init_cpus(MachineState *machine) { MachineClass *mc = MACHINE_GET_CLASS(machine); + S390CcwMachineClass *s390mc = S390_CCW_MACHINE_CLASS(mc); int i; + if (machine->smp.threads > s390mc->max_threads) { + error_report("S390 does not support more than %d threads.", + s390mc->max_threads); + exit(1); + } + /* initialize possible_cpus */ mc->possible_cpu_arch_ids(machine); @@ -731,6 +738,7 @@ static void ccw_machine_class_init(ObjectClass *oc, void *data) s390mc->cpu_model_allowed = true; s390mc->css_migration_enabled = true; s390mc->hpage_1m_allowed = true; + s390mc->max_threads = 1; mc->init = ccw_init; mc->reset = s390_machine_reset; mc->block_default_type = IF_VIRTIO; @@ -859,8 +867,11 @@ static void ccw_machine_7_1_instance_options(MachineState *machine) static void ccw_machine_7_1_class_options(MachineClass *mc) { + S390CcwMachineClass *s390mc = S390_CCW_MACHINE_CLASS(mc); + ccw_machine_7_2_class_options(mc); compat_props_add(mc->compat_props, hw_compat_7_1, hw_compat_7_1_len); + s390mc->max_threads = S390_MAX_CPUS; } DEFINE_CCW_MACHINE(7_1, "7.1", false); diff --git a/include/hw/s390x/s390-virtio-ccw.h b/include/hw/s390x/s390-virtio-ccw.h index 8a0090a071..4f8a39abda 100644 --- a/include/hw/s390x/s390-virtio-ccw.h +++ b/include/hw/s390x/s390-virtio-ccw.h @@ -40,6 +40,7 @@ struct S390CcwMachineClass { bool cpu_model_allowed; bool css_migration_enabled; bool hpage_1m_allowed; + int max_threads; }; /* runtime-instrumentation allowed by the machine */ -- 2.39.5