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[PULL 04/19] hw/arm/virt: Don't create device-tree node for empty NUMA n
From: |
Richard Henderson |
Subject: |
[PULL 04/19] hw/arm/virt: Don't create device-tree node for empty NUMA node |
Date: |
Thu, 21 Oct 2021 08:25:26 -0700 |
From: Gavin Shan <gshan@redhat.com>
The empty NUMA node, where no memory resides, are allowed. For
example, the following command line specifies two empty NUMA nodes.
With this, QEMU fails to boot because of the conflicting device-tree
node names, as the following error message indicates.
/home/gavin/sandbox/qemu.main/build/qemu-system-aarch64 \
-accel kvm -machine virt,gic-version=host \
-cpu host -smp 4,sockets=2,cores=2,threads=1 \
-m 1024M,slots=16,maxmem=64G \
-object memory-backend-ram,id=mem0,size=512M \
-object memory-backend-ram,id=mem1,size=512M \
-numa node,nodeid=0,cpus=0-1,memdev=mem0 \
-numa node,nodeid=1,cpus=2-3,memdev=mem1 \
-numa node,nodeid=2 \
-numa node,nodeid=3
:
qemu-system-aarch64: FDT: Failed to create subnode /memory@80000000:
FDT_ERR_EXISTS
As specified by linux device-tree binding document, the device-tree
nodes for these empty NUMA nodes shouldn't be generated. However,
the corresponding NUMA node IDs should be included in the distance
map. The memory hotplug through device-tree on ARM64 isn't existing
so far and it's not necessary to require the user to provide a distance
map. Furthermore, the default distance map Linux generates may even be
sufficient. So this simply skips populating the device-tree nodes for
these empty NUMA nodes to avoid the error, so that QEMU can be started
successfully.
Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Message-Id: <20211015124246.23073-1-gshan@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
hw/arm/boot.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/hw/arm/boot.c b/hw/arm/boot.c
index 57efb61ee4..74ad397b1f 100644
--- a/hw/arm/boot.c
+++ b/hw/arm/boot.c
@@ -599,10 +599,23 @@ int arm_load_dtb(hwaddr addr, const struct arm_boot_info
*binfo,
}
g_strfreev(node_path);
+ /*
+ * We drop all the memory nodes which correspond to empty NUMA nodes
+ * from the device tree, because the Linux NUMA binding document
+ * states they should not be generated. Linux will get the NUMA node
+ * IDs of the empty NUMA nodes from the distance map if they are needed.
+ * This means QEMU users may be obliged to provide command lines which
+ * configure distance maps when the empty NUMA node IDs are needed and
+ * Linux's default distance map isn't sufficient.
+ */
if (ms->numa_state != NULL && ms->numa_state->num_nodes > 0) {
mem_base = binfo->loader_start;
for (i = 0; i < ms->numa_state->num_nodes; i++) {
mem_len = ms->numa_state->nodes[i].node_mem;
+ if (!mem_len) {
+ continue;
+ }
+
rc = fdt_add_memory_node(fdt, acells, mem_base,
scells, mem_len, i);
if (rc < 0) {
--
2.25.1
- [PULL 00/19] target/arm patch queue, Richard Henderson, 2021/10/21
- [PULL 00/19] target/arm patch queue, Richard Henderson, 2021/10/21
- [PULL 01/19] tests/acpi: Get prepared for IORT E.b revision upgrade, Richard Henderson, 2021/10/21
- [PULL 02/19] hw/arm/virt-acpi-build: IORT upgrade up to revision E.b, Richard Henderson, 2021/10/21
- [PULL 04/19] hw/arm/virt: Don't create device-tree node for empty NUMA node,
Richard Henderson <=
- [PULL 03/19] tests/acpi: Generate reference blob for IORT rev E.b, Richard Henderson, 2021/10/21
- [PULL 06/19] roms/edk2: Only initialize required submodules, Richard Henderson, 2021/10/21
- [PULL 05/19] roms/edk2: Only init brotli submodule to build BaseTools, Richard Henderson, 2021/10/21
- [PULL 11/19] bios-tables-test: Generate reference table for virt/DBG2, Richard Henderson, 2021/10/21
- [PULL 09/19] tests/acpi: Add void table for virt/DBG2 bios-tables-test, Richard Henderson, 2021/10/21
- [PULL 08/19] hw/elf_ops.h: switch to ssize_t for elf loader return type, Richard Henderson, 2021/10/21
- [PULL 07/19] hw/arm/sbsa-ref: Fixed cpu type error message typo., Richard Henderson, 2021/10/21
- [PULL 12/19] hw/arm/virt: Only describe cpu topology since virt-6.2, Richard Henderson, 2021/10/21
- [PULL 14/19] hw/arm/virt: Add cpu-map to device tree, Richard Henderson, 2021/10/21
- [PULL 15/19] hw/acpi/aml-build: Add Processor hierarchy node structure, Richard Henderson, 2021/10/21