diff mbox series

[RFC,3/5] hw/arm/virt-acpi-build: distinguish possible and present cpus

Message ID 20210225085627.2263-4-fangying1@huawei.com (mailing list archive)
State New, archived
Headers show
Series hw/arm/virt: Introduce cpu topology support | expand

Commit Message

fangying Feb. 25, 2021, 8:56 a.m. UTC 
When building ACPI tables regarding CPUs we should always build
them for the number of possible CPUs, not the number of present
CPUs. We then ensure only the present CPUs are enabled in madt.
Furthermore, it is also needed if we are going to support CPU
hotplug in the future.

This patch is a rework based on Andrew Jones's contribution at
https://lists.gnu.org/archive/html/qemu-arm/2018-07/msg00076.html

Signed-off-by: Ying Fang <fangying1@huawei.com>
---
 hw/arm/virt-acpi-build.c | 14 ++++++++++----
 hw/arm/virt.c            |  2 ++
 2 files changed, 12 insertions(+), 4 deletions(-)

Comments

Andrew Jones Feb. 25, 2021, 11:26 a.m. UTC | #1 
On Thu, Feb 25, 2021 at 04:56:25PM +0800, Ying Fang wrote:
> When building ACPI tables regarding CPUs we should always build
> them for the number of possible CPUs, not the number of present
> CPUs. We then ensure only the present CPUs are enabled in madt.
> Furthermore, it is also needed if we are going to support CPU
> hotplug in the future.
> 
> This patch is a rework based on Andrew Jones's contribution at
> https://lists.gnu.org/archive/html/qemu-arm/2018-07/msg00076.html
> 
> Signed-off-by: Ying Fang <fangying1@huawei.com>
> ---
>  hw/arm/virt-acpi-build.c | 14 ++++++++++----
>  hw/arm/virt.c            |  2 ++
>  2 files changed, 12 insertions(+), 4 deletions(-)
> 
> diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
> index f9c9df916c..bb91152fe2 100644
> --- a/hw/arm/virt-acpi-build.c
> +++ b/hw/arm/virt-acpi-build.c
> @@ -61,13 +61,16 @@
>  
>  static void acpi_dsdt_add_cpus(Aml *scope, VirtMachineState *vms)
>  {
> -    MachineState *ms = MACHINE(vms);
> +    CPUArchIdList *possible_cpus = MACHINE(vms)->possible_cpus;
>      uint16_t i;
>  
> -    for (i = 0; i < ms->smp.cpus; i++) {
> +    for (i = 0; i < possible_cpus->len; i++) {

Switching from ms->smp.cpus to possible_cpus->len makes some sense
here, since we're going to be using possible_cpus->cpus[] inside
the loop. Otherwise, I'd prefer switching to ms->smp.max_cpus.

>          Aml *dev = aml_device("C%.03X", i);
>          aml_append(dev, aml_name_decl("_HID", aml_string("ACPI0007")));
>          aml_append(dev, aml_name_decl("_UID", aml_int(i)));
> +        if (possible_cpus->cpus[i].cpu == NULL) {
> +            aml_append(dev, aml_name_decl("_STA", aml_int(0)));
> +        }
>          aml_append(scope, dev);
>      }
>  }
> @@ -479,6 +482,7 @@ build_madt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
>      const int *irqmap = vms->irqmap;
>      AcpiMadtGenericDistributor *gicd;
>      AcpiMadtGenericMsiFrame *gic_msi;
> +    CPUArchIdList *possible_cpus = MACHINE(vms)->possible_cpus;
>      int i;
>  
>      acpi_data_push(table_data, sizeof(AcpiMultipleApicTable));
> @@ -489,7 +493,7 @@ build_madt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
>      gicd->base_address = cpu_to_le64(memmap[VIRT_GIC_DIST].base);
>      gicd->version = vms->gic_version;
>  
> -    for (i = 0; i < MACHINE(vms)->smp.cpus; i++) {
> +    for (i = 0; i < possible_cpus->len; i++) {

Same comment as above.

>          AcpiMadtGenericCpuInterface *gicc = acpi_data_push(table_data,
>                                                             sizeof(*gicc));
>          ARMCPU *armcpu = ARM_CPU(qemu_get_cpu(i));
> @@ -504,7 +508,9 @@ build_madt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
>          gicc->cpu_interface_number = cpu_to_le32(i);
>          gicc->arm_mpidr = cpu_to_le64(armcpu->mp_affinity);
>          gicc->uid = cpu_to_le32(i);
> -        gicc->flags = cpu_to_le32(ACPI_MADT_GICC_ENABLED);
> +        if (possible_cpus->cpus[i].cpu != NULL) {
> +            gicc->flags = cpu_to_le32(ACPI_MADT_GICC_ENABLED);
> +        }
>  
>          if (arm_feature(&armcpu->env, ARM_FEATURE_PMU)) {
>              gicc->performance_interrupt = cpu_to_le32(PPI(VIRTUAL_PMU_IRQ));
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index c133b342b8..75659502e2 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -2047,6 +2047,8 @@ static void machvirt_init(MachineState *machine)
>  
>          qdev_realize(DEVICE(cpuobj), NULL, &error_fatal);
>          object_unref(cpuobj);
> +        /* Initialize cpu member here since cpu hotplug is not supported yet */
> +        machine->possible_cpus->cpus[n].cpu = cpuobj;

This feels like we're violating a possible_cpus abstraction. Igor?
Also, it's using cpuobj after unrefing it.

>      }
>      fdt_add_timer_nodes(vms);
>      fdt_add_cpu_nodes(vms);
> -- 
> 2.23.0
> 
> 

Thanks,
drew
diff mbox series

Patch

diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
index f9c9df916c..bb91152fe2 100644
--- a/hw/arm/virt-acpi-build.c
+++ b/hw/arm/virt-acpi-build.c
@@ -61,13 +61,16 @@ 
 
 static void acpi_dsdt_add_cpus(Aml *scope, VirtMachineState *vms)
 {
-    MachineState *ms = MACHINE(vms);
+    CPUArchIdList *possible_cpus = MACHINE(vms)->possible_cpus;
     uint16_t i;
 
-    for (i = 0; i < ms->smp.cpus; i++) {
+    for (i = 0; i < possible_cpus->len; i++) {
         Aml *dev = aml_device("C%.03X", i);
         aml_append(dev, aml_name_decl("_HID", aml_string("ACPI0007")));
         aml_append(dev, aml_name_decl("_UID", aml_int(i)));
+        if (possible_cpus->cpus[i].cpu == NULL) {
+            aml_append(dev, aml_name_decl("_STA", aml_int(0)));
+        }
         aml_append(scope, dev);
     }
 }
@@ -479,6 +482,7 @@  build_madt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
     const int *irqmap = vms->irqmap;
     AcpiMadtGenericDistributor *gicd;
     AcpiMadtGenericMsiFrame *gic_msi;
+    CPUArchIdList *possible_cpus = MACHINE(vms)->possible_cpus;
     int i;
 
     acpi_data_push(table_data, sizeof(AcpiMultipleApicTable));
@@ -489,7 +493,7 @@  build_madt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
     gicd->base_address = cpu_to_le64(memmap[VIRT_GIC_DIST].base);
     gicd->version = vms->gic_version;
 
-    for (i = 0; i < MACHINE(vms)->smp.cpus; i++) {
+    for (i = 0; i < possible_cpus->len; i++) {
         AcpiMadtGenericCpuInterface *gicc = acpi_data_push(table_data,
                                                            sizeof(*gicc));
         ARMCPU *armcpu = ARM_CPU(qemu_get_cpu(i));
@@ -504,7 +508,9 @@  build_madt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
         gicc->cpu_interface_number = cpu_to_le32(i);
         gicc->arm_mpidr = cpu_to_le64(armcpu->mp_affinity);
         gicc->uid = cpu_to_le32(i);
-        gicc->flags = cpu_to_le32(ACPI_MADT_GICC_ENABLED);
+        if (possible_cpus->cpus[i].cpu != NULL) {
+            gicc->flags = cpu_to_le32(ACPI_MADT_GICC_ENABLED);
+        }
 
         if (arm_feature(&armcpu->env, ARM_FEATURE_PMU)) {
             gicc->performance_interrupt = cpu_to_le32(PPI(VIRTUAL_PMU_IRQ));
diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index c133b342b8..75659502e2 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -2047,6 +2047,8 @@  static void machvirt_init(MachineState *machine)
 
         qdev_realize(DEVICE(cpuobj), NULL, &error_fatal);
         object_unref(cpuobj);
+        /* Initialize cpu member here since cpu hotplug is not supported yet */
+        machine->possible_cpus->cpus[n].cpu = cpuobj;
     }
     fdt_add_timer_nodes(vms);
     fdt_add_cpu_nodes(vms);