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arch: Fix AArch64 socket setting in CPU topology

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Before Linux v6.0, AArch64 didn't support "socket" in "cpu-map"
(CPU topology) of FDT.

We found that clusters can be used in the same way of sockets. That is
the way we implemented the socket settings in Cloud Hypervisor. But in
fact it was a bug.

Linux commit 26a2b7 fixed the mistake. So the cluster nodes can no
longer act as sockets. And in a following commit dea8c0, sockets were
supported.

This patch fixed the way to configure sockets. In each socket, a default
cluster was added to contain all the cores, because cluster layer is
mandatory in CPU topology on AArch64.

This fix will break the socket settings on the guests where the kernel
version is lower than v6.0. In that case, if socket number is set to
more than 1, the kernel will treat that as FDT mistake and all the CPUs
will be put in single cluster of single socket.

The patch only impacts the case of using FDT, not ACPI.

Signed-off-by: Michael Zhao <michael.zhao@arm.com>
This commit is contained in:
Michael Zhao 2023-01-28 19:27:39 +08:00 committed by Rob Bradford
parent d5ce855649
commit 4a51a6615f
1 changed files with 9 additions and 4 deletions
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13
arch/src/aarch64/fdt.rs
View File

@ -191,9 +191,13 @@ fn create_cpu_nodes(
let cpu_map_node = fdt.begin_node("cpu-map")?;
// Create device tree nodes with regard of above mapping.
for cluster_idx in 0..packages {
let cluster_name = format!("cluster{cluster_idx:x}");
let cluster_node = fdt.begin_node(&cluster_name)?;
for package_idx in 0..packages {
let package_name = format!("socket{package_idx:x}");
let package_node = fdt.begin_node(&package_name)?;
// Cluster is the container of cores, and it is mandatory in the CPU topology.
// Add a default "cluster0" in each socket/package.
let cluster_node = fdt.begin_node("cluster0")?;
for core_idx in 0..cores_per_package {
let core_name = format!("core{core_idx:x}");
@ -202,7 +206,7 @@ fn create_cpu_nodes(
for thread_idx in 0..threads_per_core {
let thread_name = format!("thread{thread_idx:x}");
let thread_node = fdt.begin_node(&thread_name)?;
let cpu_idx = threads_per_core * cores_per_package * cluster_idx
let cpu_idx = threads_per_core * cores_per_package * package_idx
+ threads_per_core * core_idx
+ thread_idx;
fdt.property_u32("cpu", cpu_idx as u32 + FIRST_VCPU_PHANDLE)?;
@ -212,6 +216,7 @@ fn create_cpu_nodes(
fdt.end_node(core_node)?;
}
fdt.end_node(cluster_node)?;
fdt.end_node(package_node)?;
}
fdt.end_node(cpu_map_node)?;
} else {