From 7b8be49d36fc0a48e41ede7ba7e046c1db2b89bc Mon Sep 17 00:00:00 2001 From: Dou Liyang Date: Tue, 14 Nov 2017 10:34:01 +0800 Subject: [PATCH] NUMA: Enable adding NUMA node implicitly Linux and Windows need ACPI SRAT table to make memory hotplug work properly, however currently QEMU doesn't create SRAT table if numa options aren't present on CLI. Which breaks both linux and windows guests in certain conditions: * Windows: won't enable memory hotplug without SRAT table at all * Linux: if QEMU is started with initial memory all below 4Gb and no SRAT table present, guest kernel will use nommu DMA ops, which breaks 32bit hw drivers when memory is hotplugged and guest tries to use it with that drivers. Fix above issues by automatically creating a numa node when QEMU is started with memory hotplug enabled but without '-numa' options on CLI. (PS: auto-create numa node only for new machine types so not to break migration). Which would provide SRAT table to guests without explicit -numa options on CLI and would allow: * Windows: to enable memory hotplug * Linux: switch to SWIOTLB DMA ops, to bounce DMA transfers to 32bit allocated buffers that legacy drivers/hw can handle. [Rewritten by Igor] Reported-by: Thadeu Lima de Souza Cascardo Suggested-by: Igor Mammedov Signed-off-by: Dou Liyang Cc: Paolo Bonzini Cc: Richard Henderson Cc: Eduardo Habkost Cc: "Michael S. Tsirkin" Cc: Marcel Apfelbaum Cc: Igor Mammedov Cc: David Hildenbrand Cc: Thomas Huth Cc: Alistair Francis Cc: Takao Indoh Cc: Izumi Taku Reviewed-by: Igor Mammedov Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/i386/pc.c | 1 + hw/i386/pc_piix.c | 1 + hw/i386/pc_q35.c | 1 + include/hw/boards.h | 1 + numa.c | 21 ++++++++++++++++++++- vl.c | 3 +-- 6 files changed, 25 insertions(+), 3 deletions(-) diff --git a/hw/i386/pc.c b/hw/i386/pc.c index fafe5ba5cd..c3afe5b7f1 100644 --- a/hw/i386/pc.c +++ b/hw/i386/pc.c @@ -2347,6 +2347,7 @@ static void pc_machine_class_init(ObjectClass *oc, void *data) mc->cpu_index_to_instance_props = pc_cpu_index_to_props; mc->get_default_cpu_node_id = pc_get_default_cpu_node_id; mc->possible_cpu_arch_ids = pc_possible_cpu_arch_ids; + mc->auto_enable_numa_with_memhp = true; mc->has_hotpluggable_cpus = true; mc->default_boot_order = "cad"; mc->hot_add_cpu = pc_hot_add_cpu; diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c index f79d5cb694..5e47528993 100644 --- a/hw/i386/pc_piix.c +++ b/hw/i386/pc_piix.c @@ -446,6 +446,7 @@ static void pc_i440fx_2_10_machine_options(MachineClass *m) m->is_default = 0; m->alias = NULL; SET_MACHINE_COMPAT(m, PC_COMPAT_2_10); + m->auto_enable_numa_with_memhp = false; } DEFINE_I440FX_MACHINE(v2_10, "pc-i440fx-2.10", NULL, diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c index da3ea602e1..d6060043ac 100644 --- a/hw/i386/pc_q35.c +++ b/hw/i386/pc_q35.c @@ -318,6 +318,7 @@ static void pc_q35_2_10_machine_options(MachineClass *m) m->alias = NULL; SET_MACHINE_COMPAT(m, PC_COMPAT_2_10); m->numa_auto_assign_ram = numa_legacy_auto_assign_ram; + m->auto_enable_numa_with_memhp = false; } DEFINE_Q35_MACHINE(v2_10, "pc-q35-2.10", NULL, diff --git a/include/hw/boards.h b/include/hw/boards.h index 62f160e0aa..156b16f7a6 100644 --- a/include/hw/boards.h +++ b/include/hw/boards.h @@ -197,6 +197,7 @@ struct MachineClass { bool ignore_memory_transaction_failures; int numa_mem_align_shift; const char **valid_cpu_types; + bool auto_enable_numa_with_memhp; void (*numa_auto_assign_ram)(MachineClass *mc, NodeInfo *nodes, int nb_nodes, ram_addr_t size); diff --git a/numa.c b/numa.c index 8d78d959f6..7151b24d1c 100644 --- a/numa.c +++ b/numa.c @@ -216,6 +216,7 @@ static void parse_numa_node(MachineState *ms, NumaNodeOptions *node, } numa_info[nodenr].present = true; max_numa_nodeid = MAX(max_numa_nodeid, nodenr + 1); + nb_numa_nodes++; } static void parse_numa_distance(NumaDistOptions *dist, Error **errp) @@ -282,7 +283,6 @@ static int parse_numa(void *opaque, QemuOpts *opts, Error **errp) if (err) { goto end; } - nb_numa_nodes++; break; case NUMA_OPTIONS_TYPE_DIST: parse_numa_distance(&object->u.dist, &err); @@ -433,6 +433,25 @@ void parse_numa_opts(MachineState *ms) exit(1); } + /* + * If memory hotplug is enabled (slots > 0) but without '-numa' + * options explicitly on CLI, guestes will break. + * + * Windows: won't enable memory hotplug without SRAT table at all + * + * Linux: if QEMU is started with initial memory all below 4Gb + * and no SRAT table present, guest kernel will use nommu DMA ops, + * which breaks 32bit hw drivers when memory is hotplugged and + * guest tries to use it with that drivers. + * + * Enable NUMA implicitly by adding a new NUMA node automatically. + */ + if (ms->ram_slots > 0 && nb_numa_nodes == 0 && + mc->auto_enable_numa_with_memhp) { + NumaNodeOptions node = { }; + parse_numa_node(ms, &node, NULL); + } + assert(max_numa_nodeid <= MAX_NODES); /* No support for sparse NUMA node IDs yet: */ diff --git a/vl.c b/vl.c index 7372424fa7..1ad1c04637 100644 --- a/vl.c +++ b/vl.c @@ -4690,8 +4690,6 @@ int main(int argc, char **argv, char **envp) default_drive(default_floppy, snapshot, IF_FLOPPY, 0, FD_OPTS); default_drive(default_sdcard, snapshot, IF_SD, 0, SD_OPTS); - parse_numa_opts(current_machine); - if (qemu_opts_foreach(qemu_find_opts("mon"), mon_init_func, NULL, NULL)) { exit(1); @@ -4741,6 +4739,7 @@ int main(int argc, char **argv, char **envp) current_machine->boot_order = boot_order; current_machine->cpu_model = cpu_model; + parse_numa_opts(current_machine); /* parse features once if machine provides default cpu_type */ if (machine_class->default_cpu_type) {