In QEMU, if we enable NUMA and have nodes, QEMU will build ACPI SRAT table
for transfering NUMA configuration to the guest. So, the maximum memory in
SRAT can be used to determine whether to use the swiotlb for IOMMU or not.
However, if QEmu doesn't enable NUMA explicitly on CLI, The SRAT will
never be built. When memory hotplug is enabled, some guest's devices may
start failing due to SWIOTLB is disabled.
Add numa_implicit_add_node0 in struct MachineClass, Invoke it before QEMU
parse NUMA options to enable adding NUMA node implicitly.
Reported-by: Thadeu Lima de Souza Cascardo <address@hidden>
Suggested-by: Igor Mammedov <address@hidden>
Signed-off-by: Dou Liyang <address@hidden>
Cc: Paolo Bonzini <address@hidden>
Cc: Richard Henderson <address@hidden>
Cc: Eduardo Habkost <address@hidden>
Cc: "Michael S. Tsirkin" <address@hidden>
Cc: Marcel Apfelbaum <address@hidden>
Cc: Igor Mammedov <address@hidden>
Cc: David Hildenbrand <address@hidden>
Cc: Thomas Huth <address@hidden>
Cc: Alistair Francis <address@hidden>
Cc: address@hidden
Cc: Takao Indoh <address@hidden>
Cc: Izumi Taku <address@hidden>
---
hw/i386/pc.c | 6 ++++++
include/hw/boards.h | 4 ++++
vl.c | 14 ++++++++++++++
3 files changed, 24 insertions(+)
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 2108104..3c40117 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -2308,6 +2308,11 @@ static const CPUArchIdList
*pc_possible_cpu_arch_ids(MachineState *ms)
return ms->possible_cpus;
}
+static void numa_implicit_add_node0(void)
+{
+ qemu_opts_parse_noisily(qemu_find_opts("numa"), "node", true);
+}
+
static void x86_nmi(NMIState *n, int cpu_index, Error **errp)
{
/* cpu index isn't used */
@@ -2349,6 +2354,7 @@ static void pc_machine_class_init(ObjectClass *oc, void
*data)
mc->get_hotplug_handler = pc_get_hotpug_handler;
mc->cpu_index_to_instance_props = pc_cpu_index_to_props;
mc->possible_cpu_arch_ids = pc_possible_cpu_arch_ids;
+ mc->numa_implicit_add_node0 = numa_implicit_add_node0;
mc->has_hotpluggable_cpus = true;
mc->default_boot_order = "cad";
mc->hot_add_cpu = pc_hot_add_cpu;
diff --git a/include/hw/boards.h b/include/hw/boards.h
index 7f044d1..898d841 100644
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -141,6 +141,8 @@ typedef struct {
* should instead use "unimplemented-device" for all memory ranges where
* the guest will attempt to probe for a device that QEMU doesn't
* implement and a stub device is required.
+ * @numa_implicit_add_node0:
+ * Enable NUMA implicitly by add a NUMA node.
*/
struct MachineClass {
/*< private >*/
@@ -191,6 +193,8 @@ struct MachineClass {
CpuInstanceProperties (*cpu_index_to_instance_props)(MachineState *machine,
unsigned cpu_index);
const CPUArchIdList *(*possible_cpu_arch_ids)(MachineState *machine);
+
+ void (*numa_implicit_add_node0)(void);
};
/**
diff --git a/vl.c b/vl.c
index fb1f05b..814a5fa 100644
--- a/vl.c
+++ b/vl.c
@@ -3030,6 +3030,7 @@ int main(int argc, char **argv, char **envp)
Error *main_loop_err = NULL;
Error *err = NULL;
bool list_data_dirs = false;
+ bool has_numa_config_in_CLI = false;
typedef struct BlockdevOptions_queue {
BlockdevOptions *bdo;
Location loc;
@@ -3293,6 +3294,7 @@ int main(int argc, char **argv, char **envp)
if (!opts) {
exit(1);
}
+ has_numa_config_in_CLI = true;
break;
case QEMU_OPTION_display:
display_type = select_display(optarg);
@@ -4585,6 +4587,18 @@ 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);
+ /*
+ * If memory hotplug is enabled i.e. slots > 0 and user hasn't add
+ * NUMA nodes explicitly on CLI
+ *
+ * Enable NUMA implicitly for guest to know the maximum memory
+ * from ACPI SRAT table, which is used for SWIOTLB.
+ */
+ if (ram_slots > 0 && !has_numa_config_in_CLI) {
+ if (machine_class->numa_implicit_add_node0) {
+ machine_class->numa_implicit_add_node0();
+ }
+ }