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[Qemu-devel] [PATCH v5 2/4] acpi: provide _PXM method for CPU devices if
From: |
Igor Mammedov |
Subject: |
[Qemu-devel] [PATCH v5 2/4] acpi: provide _PXM method for CPU devices if QEMU is started numa enabled |
Date: |
Wed, 5 Oct 2016 17:51:24 +0200 |
Workaround for long standing issue where Linux kernel
assigns hotplugged CPU to 1st numa node as it discards
proximity for possible CPUs from SRAT after it's parsed.
_PXM method allows linux query proximity directly from
hotplugged CPU object, which allows Linux to assing CPU
to the correct numa node.
Signed-off-by: Igor Mammedov <address@hidden>
Reviewed-by: Marcel Apfelbaum <address@hidden>
---
hw/acpi/cpu.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/hw/acpi/cpu.c b/hw/acpi/cpu.c
index c13b65c..902f5c9 100644
--- a/hw/acpi/cpu.c
+++ b/hw/acpi/cpu.c
@@ -4,6 +4,7 @@
#include "qapi/error.h"
#include "qapi-event.h"
#include "trace.h"
+#include "sysemu/numa.h"
#define ACPI_CPU_HOTPLUG_REG_LEN 12
#define ACPI_CPU_SELECTOR_OFFSET_WR 0
@@ -503,6 +504,7 @@ void build_cpus_aml(Aml *table, MachineState *machine,
CPUHotplugFeatures opts,
/* build Processor object for each processor */
for (i = 0; i < arch_ids->len; i++) {
+ int j;
Aml *dev;
Aml *uid = aml_int(i);
GArray *madt_buf = g_array_new(0, 1, 1);
@@ -546,6 +548,16 @@ void build_cpus_aml(Aml *table, MachineState *machine,
CPUHotplugFeatures opts,
aml_arg(1), aml_arg(2))
);
aml_append(dev, method);
+
+ /* Linux guests discard SRAT info for non-present CPUs
+ * as a result _PXM is required for all CPUs which might
+ * be hot-plugged. For simplicity, add it for all CPUs.
+ */
+ j = numa_get_node_for_cpu(i);
+ if (j < nb_numa_nodes) {
+ aml_append(dev, aml_name_decl("_PXM", aml_int(j)));
+ }
+
aml_append(cpus_dev, dev);
}
}
--
2.7.4