From 97f4effeb6083f3c15f48cf4eea0c16552a9330a Mon Sep 17 00:00:00 2001 From: Yicong Yang Date: Thu, 29 Dec 2022 14:55:09 +0800 Subject: [PATCH] hw/acpi/aml-build: Only generate cluster node in PPTT when specified Currently we'll always generate a cluster node no matter user has specified '-smp clusters=X' or not. Cluster is an optional level and will participant the building of Linux scheduling domains and only appears on a few platforms. It's unncessary to always build it when it cannot reflect the real topology on platforms having no cluster implementation and to avoid affecting the linux scheduling domains in the VM. So only generate the cluster topology in ACPI PPTT when the user has specified it explicitly in -smp. Tested qemu-system-aarch64 with `-smp 8` and linux 6.1-rc1, without this patch: estuary:/sys/devices/system/cpu/cpu0/topology$ cat cluster_* ff # cluster_cpus 0-7 # cluster_cpus_list 56 # cluster_id with this patch: estuary:/sys/devices/system/cpu/cpu0/topology$ cat cluster_* ff # cluster_cpus 0-7 # cluster_cpus_list 36 # cluster_id, with no cluster node kernel will make it to physical package id Acked-by: Michael S. Tsirkin Reviewed-by: Yanan Wang Tested-by: Yanan Wang Signed-off-by: Yicong Yang Message-Id: <20221229065513.55652-3-yangyicong@huawei.com> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/acpi/aml-build.c | 2 +- hw/core/machine-smp.c | 2 ++ include/hw/boards.h | 3 +++ qemu-options.hx | 3 +++ 4 files changed, 9 insertions(+), 1 deletion(-) diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c index 42feb4d4d7..ea331a20d1 100644 --- a/hw/acpi/aml-build.c +++ b/hw/acpi/aml-build.c @@ -2030,7 +2030,7 @@ void build_pptt(GArray *table_data, BIOSLinker *linker, MachineState *ms, 0, socket_id, NULL, 0); } - if (mc->smp_props.clusters_supported) { + if (mc->smp_props.clusters_supported && mc->smp_props.has_clusters) { if (cpus->cpus[n].props.cluster_id != cluster_id) { assert(cpus->cpus[n].props.cluster_id > cluster_id); cluster_id = cpus->cpus[n].props.cluster_id; diff --git a/hw/core/machine-smp.c b/hw/core/machine-smp.c index b39ed21e65..c3dab007da 100644 --- a/hw/core/machine-smp.c +++ b/hw/core/machine-smp.c @@ -158,6 +158,8 @@ void machine_parse_smp_config(MachineState *ms, ms->smp.threads = threads; ms->smp.max_cpus = maxcpus; + mc->smp_props.has_clusters = config->has_clusters; + /* sanity-check of the computed topology */ if (sockets * dies * clusters * cores * threads != maxcpus) { g_autofree char *topo_msg = cpu_hierarchy_to_string(ms); diff --git a/include/hw/boards.h b/include/hw/boards.h index d18d6d0073..b0abbdd5dc 100644 --- a/include/hw/boards.h +++ b/include/hw/boards.h @@ -130,11 +130,14 @@ typedef struct { * @prefer_sockets - whether sockets are preferred over cores in smp parsing * @dies_supported - whether dies are supported by the machine * @clusters_supported - whether clusters are supported by the machine + * @has_clusters - whether clusters are explicitly specified in the user + * provided SMP configuration */ typedef struct { bool prefer_sockets; bool dies_supported; bool clusters_supported; + bool has_clusters; } SMPCompatProps; /** diff --git a/qemu-options.hx b/qemu-options.hx index 7f99d15b23..8662568324 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -343,6 +343,9 @@ SRST :: -smp 2 + + Note: The cluster topology will only be generated in ACPI and exposed + to guest if it's explicitly specified in -smp. ERST DEF("numa", HAS_ARG, QEMU_OPTION_numa,