On 2/25/2021 7:16 PM, Andrew Jones wrote:
Hi Ying Fang,
The only difference between this and what I have in my tree[*]
is the removal of the socket node (which has been in the Linux
docs since June 2019). Any reason why you removed that node? In
any case, I think I deserve a bit more credit for this patch.
Sorry, you surely deserve it. I forget to add it here.
Should I have a SOB of you here ?
The latest linux kernel use a four level cpu topology defined in
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/cpu/cpu-topology.txt?h=v5.11
ie. socket node, cluster node, core node, thread node.
The linux kernel 4.19 LTS use a three level cpu topology defined in
Documentation/devicetree/bindings/arm/topology.txt
ie. cluster node, core node, thread node.
Currently Qemu x86 has 4 level of cpu topology as: socket, die, core,
thread. Should arm64 active like it here ?
Further more, latest linux kernel define the cpu topology struct as.
So maybe it only cares about the socket, core, thread topology levels.
struct cpu_topology {
int thread_id;
int core_id;
int package_id;
int llc_id;
cpumask_t thread_sibling;
cpumask_t core_sibling;
cpumask_t llc_sibling;
};
[*]
https://github.com/rhdrjones/qemu/commit/35feecdd43475608c8f55973a0c159eac4aafefd
Thanks,
drew
On Thu, Feb 25, 2021 at 04:56:24PM +0800, Ying Fang wrote:
Support device tree CPU topology descriptions.
Signed-off-by: Ying Fang <fangyi...@huawei.com>
---
hw/arm/virt.c | 38 +++++++++++++++++++++++++++++++++++++-
include/hw/arm/virt.h | 1 +
2 files changed, 38 insertions(+), 1 deletion(-)
diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 371147f3ae..c133b342b8 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -351,10 +351,11 @@ static void fdt_add_cpu_nodes(const VirtMachineState *vms)
int cpu;
int addr_cells = 1;
const MachineState *ms = MACHINE(vms);
+ const VirtMachineClass *vmc = VIRT_MACHINE_GET_CLASS(vms);
int smp_cpus = ms->smp.cpus;
/*
- * From Documentation/devicetree/bindings/arm/cpus.txt
+ * See Linux Documentation/devicetree/bindings/arm/cpus.yaml
* On ARM v8 64-bit systems value should be set to 2,
* that corresponds to the MPIDR_EL1 register size.
* If MPIDR_EL1[63:32] value is equal to 0 on all CPUs
@@ -407,8 +408,42 @@ static void fdt_add_cpu_nodes(const VirtMachineState *vms)
ms->possible_cpus->cpus[cs->cpu_index].props.node_id);
}
+ if (ms->smp.cpus > 1 && !vmc->no_cpu_topology) {
+ qemu_fdt_setprop_cell(vms->fdt, nodename, "phandle",
+ qemu_fdt_alloc_phandle(vms->fdt));
+ }
+
g_free(nodename);
}
+
+ if (ms->smp.cpus > 1 && !vmc->no_cpu_topology) {
+ /*
+ * See Linux Documentation/devicetree/bindings/cpu/cpu-topology.txt
+ */
+ qemu_fdt_add_subnode(vms->fdt, "/cpus/cpu-map");
+
+ for (cpu = ms->smp.cpus - 1; cpu >= 0; cpu--) {
+ char *cpu_path = g_strdup_printf("/cpus/cpu@%d", cpu);
+ char *map_path;
+
+ if (ms->smp.threads > 1) {
+ map_path = g_strdup_printf(
+ "/cpus/cpu-map/%s%d/%s%d/%s%d",
+ "cluster", cpu / (ms->smp.cores * ms->smp.threads),
a cluster node may be replaced by socket to keep accord with the latest
kernel.
+ "core", (cpu / ms->smp.threads) % ms->smp.cores,
+ "thread", cpu % ms->smp.threads);
+ } else {
+ map_path = g_strdup_printf(
+ "/cpus/cpu-map/%s%d/%s%d",
+ "cluster", cpu / ms->smp.cores,
+ "core", cpu % ms->smp.cores);
+ }
+ qemu_fdt_add_path(vms->fdt, map_path);
+ qemu_fdt_setprop_phandle(vms->fdt, map_path, "cpu", cpu_path);
+ g_free(map_path);
+ g_free(cpu_path);
+ }
+ }
}
static void fdt_add_its_gic_node(VirtMachineState *vms)
@@ -2742,6 +2777,7 @@ static void virt_machine_5_2_options(MachineClass *mc)
virt_machine_6_0_options(mc);
compat_props_add(mc->compat_props, hw_compat_5_2, hw_compat_5_2_len);
vmc->no_secure_gpio = true;
+ vmc->no_cpu_topology = true;
}
DEFINE_VIRT_MACHINE(5, 2)
diff --git a/include/hw/arm/virt.h b/include/hw/arm/virt.h
index ee9a93101e..7ef6d08ac3 100644
--- a/include/hw/arm/virt.h
+++ b/include/hw/arm/virt.h
@@ -129,6 +129,7 @@ struct VirtMachineClass {
bool no_kvm_steal_time;
bool acpi_expose_flash;
bool no_secure_gpio;
+ bool no_cpu_topology;
};
struct VirtMachineState {
--
2.23.0
.