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[Qemu-arm] [RFC PATCH 5/6] virt-acpi-build: add PPTT table
From: |
Andrew Jones |
Subject: |
[Qemu-arm] [RFC PATCH 5/6] virt-acpi-build: add PPTT table |
Date: |
Wed, 4 Jul 2018 14:49:22 +0200 |
The ACPI PPTT table supports topology descriptions for ACPI
guests. Note, while a DT boot Linux guest with a non-flat CPU
topology will see socket and core IDs being sequential integers
starting from zero, e.g. with -smp 4,sockets=2,cores=2,threads=1
a DT boot produces
cpu: 0 package_id: 0 core_id: 0
cpu: 1 package_id: 0 core_id: 1
cpu: 2 package_id: 1 core_id: 0
cpu: 3 package_id: 1 core_id: 1
an ACPI boot produces
cpu: 0 package_id: 36 core_id: 0
cpu: 1 package_id: 36 core_id: 1
cpu: 2 package_id: 96 core_id: 2
cpu: 3 package_id: 96 core_id: 3
This is due to several reasons:
1) DT cpu nodes do not have an equivalent field to what the PPTT
ACPI Processor ID must be, i.e. something equal to the MADT CPU
UID or equal to the UID of an ACPI processor container. In both
ACPI cases those are platform dependant IDs assigned by the
vendor.
2) While QEMU is the vendor for a guest, if the topology specifies
SMT (> 1 thread), then, with ACPI, it is impossible to assign a
core-id the same value as a package-id, thus it is not possible
to have package-id=0 and core-id=0. This is because package and
core containers must be in the same ACPI namespace and therefore
must have unique UIDs.
3) ACPI processor containers are not required for PPTT tables to
be used and, due to the limitations of which IDs are selected
described above in (2), they are not helpful for QEMU, so we
don't build them with this patch. In the absence of them, Linux
assigns its own unique IDs. The maintainers have chosen not to use
counters from zero, but rather ACPI table offsets, which explains
why the numbers are so much larger than with DT.
4) When there is no SMT (threads=1) the core IDs for ACPI boot guests
match the logical CPU IDs, because these IDs must be equal to the
MADT CPU UID (as no processor containers are present), and QEMU
uses the logical CPU ID for these MADT IDs.
Cc: Igor Mammedov <address@hidden>
Cc: Shannon Zhao <address@hidden>
Cc: "Michael S. Tsirkin" <address@hidden>
Signed-off-by: Andrew Jones <address@hidden>
---
hw/acpi/aml-build.c | 50 +++++++++++++++++++++++++++++++++++++
hw/arm/virt-acpi-build.c | 5 ++++
include/hw/acpi/aml-build.h | 2 ++
3 files changed, 57 insertions(+)
diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c
index 1e43cd736de9..37e8f5182ae9 100644
--- a/hw/acpi/aml-build.c
+++ b/hw/acpi/aml-build.c
@@ -24,6 +24,7 @@
#include "hw/acpi/aml-build.h"
#include "qemu/bswap.h"
#include "qemu/bitops.h"
+#include "sysemu/cpus.h"
#include "sysemu/numa.h"
static GArray *build_alloc_array(void)
@@ -1679,6 +1680,55 @@ void build_slit(GArray *table_data, BIOSLinker *linker)
table_data->len - slit_start, 1, NULL, NULL);
}
+/*
+ * ACPI 6.2 Processor Properties Topology Table (PPTT)
+ */
+static void build_cpu_hierarchy(GArray *tbl, uint32_t flags,
+ uint32_t parent, uint32_t id)
+{
+ build_append_byte(tbl, 0); /* Type 0 - processor */
+ build_append_byte(tbl, 20); /* Length, no private resources */
+ build_append_int_noprefix(tbl, 0, 2); /* Reserved */
+ build_append_int_noprefix(tbl, flags, 4);
+ build_append_int_noprefix(tbl, parent, 4);
+ build_append_int_noprefix(tbl, id, 4);
+ build_append_int_noprefix(tbl, 0, 4); /* Num private resources */
+}
+
+void build_pptt(GArray *table_data, BIOSLinker *linker, int possible_cpus)
+{
+ int pptt_start = table_data->len;
+ int uid = 0, cpus = 0, socket;
+
+ acpi_data_push(table_data, sizeof(AcpiTableHeader));
+
+ for (socket = 0; cpus < possible_cpus; socket++) {
+ uint32_t socket_offset = table_data->len - pptt_start;
+ int core;
+
+ build_cpu_hierarchy(table_data, 1, 0, socket);
+
+ for (core = 0; core < smp_cores; core++) {
+ uint32_t core_offset = table_data->len - pptt_start;
+ int thread;
+
+ if (smp_threads > 1) {
+ build_cpu_hierarchy(table_data, 0, socket_offset, core);
+ for (thread = 0; thread < smp_threads; thread++) {
+ build_cpu_hierarchy(table_data, 2, core_offset, uid++);
+ }
+ } else {
+ build_cpu_hierarchy(table_data, 2, socket_offset, uid++);
+ }
+ }
+ cpus += smp_cores * smp_threads;
+ }
+
+ build_header(linker, table_data,
+ (void *)(table_data->data + pptt_start), "PPTT",
+ table_data->len - pptt_start, 1, NULL, NULL);
+}
+
/* build rev1/rev3/rev5.1 FADT */
void build_fadt(GArray *tbl, BIOSLinker *linker, const AcpiFadtData *f,
const char *oem_id, const char *oem_table_id)
diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
index 1d1fc824da6f..aa77e1f018d9 100644
--- a/hw/arm/virt-acpi-build.c
+++ b/hw/arm/virt-acpi-build.c
@@ -832,6 +832,11 @@ void virt_acpi_build(VirtMachineState *vms,
AcpiBuildTables *tables)
acpi_add_table(table_offsets, tables_blob);
build_madt(tables_blob, tables->linker, vms);
+ if (!vmc->ignore_cpu_topology) {
+ acpi_add_table(table_offsets, tables_blob);
+ build_pptt(tables_blob, tables->linker, possible_cpus(vms));
+ }
+
acpi_add_table(table_offsets, tables_blob);
build_gtdt(tables_blob, tables->linker, vms);
diff --git a/include/hw/acpi/aml-build.h b/include/hw/acpi/aml-build.h
index 6c36903c0a5d..2b0fde6bd417 100644
--- a/include/hw/acpi/aml-build.h
+++ b/include/hw/acpi/aml-build.h
@@ -414,6 +414,8 @@ void build_srat_memory(AcpiSratMemoryAffinity *numamem,
uint64_t base,
void build_slit(GArray *table_data, BIOSLinker *linker);
+void build_pptt(GArray *table_data, BIOSLinker *linker, int possible_cpus);
+
void build_fadt(GArray *tbl, BIOSLinker *linker, const AcpiFadtData *f,
const char *oem_id, const char *oem_table_id);
#endif
--
2.17.1
- [Qemu-arm] [RFC PATCH 0/6] hw/arm/virt: Introduce cpu topology support, Andrew Jones, 2018/07/04
- [Qemu-arm] [RFC PATCH 1/6] hw/arm/virt: Add virt-3.1 machine type, Andrew Jones, 2018/07/04
- [Qemu-arm] [RFC PATCH 3/6] hw/arm/virt: DT: add cpu-map, Andrew Jones, 2018/07/04
- [Qemu-arm] [RFC PATCH 2/6] device_tree: add qemu_fdt_add_path, Andrew Jones, 2018/07/04
- [Qemu-arm] [RFC PATCH 4/6] hw/arm/virt-acpi-build: distinguish possible and present cpus, Andrew Jones, 2018/07/04
- [Qemu-arm] [RFC PATCH 5/6] virt-acpi-build: add PPTT table,
Andrew Jones <=
- [Qemu-arm] [RFC PATCH 6/6] hw/arm/virt: cpu topology: don't allow threads, Andrew Jones, 2018/07/04