qemu/arm-virt-Don-t-modify-smp.max_cpus-when-vcpu-hotplug.patch

From 52909d74ec37e851df3762a6eab1d7a6eeb89fba Mon Sep 17 00:00:00 2001
From: Keqian Zhu <zhukeqian1@huawei.com>
Date: Sun, 28 Apr 2024 12:56:47 +0800
Subject: [PATCH] arm/virt: Don't modify smp.max_cpus when vcpu hotplug
 disabled

The smp.max_cpus has been used when create possible_cpus, so
we must not change it after that.

We should use smp.cpus when create cpu and acpi table if vcpu
hotplug is disabled, instead of change smp.max_cpus to smp.cpus
and use it everywhere.

Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
---
 hw/arm/virt-acpi-build.c |  8 +++++++-
 hw/arm/virt.c            | 24 ++++++++++++++++++++++--
 include/hw/arm/virt.h    |  8 +++++++-
 3 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
index 99296fc6d8..179600d4fe 100644
--- a/hw/arm/virt-acpi-build.c
+++ b/hw/arm/virt-acpi-build.c
@@ -814,9 +814,15 @@ build_madt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
 {
     int i;
     VirtMachineClass *vmc = VIRT_MACHINE_GET_CLASS(vms);
+    MachineState *ms = MACHINE(vms);
     const MemMapEntry *memmap = vms->memmap;
     AcpiTable table = { .sig = "APIC", .rev = 4, .oem_id = vms->oem_id,
                         .oem_table_id = vms->oem_table_id };
+    unsigned int max_cpus = ms->smp.max_cpus;
+
+    if (!vms->cpu_hotplug_enabled) {
+        max_cpus = ms->smp.cpus;
+    }
 
     acpi_table_begin(&table, table_data);
     /* Local Interrupt Controller Address */
@@ -835,7 +841,7 @@ build_madt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
     build_append_int_noprefix(table_data, vms->gic_version, 1);
     build_append_int_noprefix(table_data, 0, 3);   /* Reserved */
 
-    for (i = 0; i < MACHINE(vms)->smp.max_cpus; i++) {
+    for (i = 0; i < max_cpus; i++) {
         CPUState *cpu = qemu_get_possible_cpu(i);
         uint64_t physical_base_address = 0, gich = 0, gicv = 0;
         uint32_t vgic_interrupt = vms->virt ? ARCH_GIC_MAINT_IRQ : 0;
diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index e4473354d4..507b09d96c 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -831,6 +831,10 @@ static void unwire_gic_cpu_irqs(VirtMachineState *vms, CPUState *cs)
     int type = vms->gic_version;
     int irq;
 
+    if (!vms->cpu_hotplug_enabled) {
+        max_cpus = ms->smp.cpus;
+    }
+
     for (irq = 0; irq < ARRAY_SIZE(timer_irq); irq++) {
         qdev_disconnect_gpio_out_named(cpudev, NULL, irq);
     }
@@ -871,6 +875,10 @@ static void wire_gic_cpu_irqs(VirtMachineState *vms, CPUState *cs)
     int intidbase;
     int irq;
 
+    if (!vms->cpu_hotplug_enabled) {
+        max_cpus = ms->smp.cpus;
+    }
+
     intidbase = NUM_IRQS + cpu * GIC_INTERNAL;
 
     for (irq = 0; irq < ARRAY_SIZE(timer_irq); irq++) {
@@ -915,6 +923,10 @@ static void create_gic(VirtMachineState *vms, MemoryRegion *mem)
     uint32_t nb_redist_regions = 0;
     int revision;
 
+    if (!vms->cpu_hotplug_enabled) {
+        max_cpus = ms->smp.cpus;
+    }
+
     if (vms->gic_version == VIRT_GIC_VERSION_2) {
         gictype = gic_class_name();
     } else {
@@ -2165,6 +2177,9 @@ static void virt_cpu_post_init(VirtMachineState *vms, MemoryRegion *sysmem)
 
         for (n = 0; n < possible_cpus->len; n++) {
             cpu = qemu_get_possible_cpu(n);
+            if (!qemu_present_cpu(cpu)) {
+                continue;
+            }
 
             if (vms->pmu) {
                 assert(arm_feature(&ARM_CPU(cpu)->env, ARM_FEATURE_PMU));
@@ -2195,6 +2210,9 @@ static void virt_cpu_post_init(VirtMachineState *vms, MemoryRegion *sysmem)
     if (kvm_enabled() || tcg_enabled()) {
         for (n = 0; n < possible_cpus->len; n++) {
             cpu = qemu_get_possible_cpu(n);
+            if (!qemu_present_cpu(cpu)) {
+                continue;
+            }
 
             /*
              * Now, GIC has been sized with possible CPUs and we dont require
@@ -2511,16 +2529,18 @@ static void machvirt_init(MachineState *machine)
         if (machine->smp.max_cpus > smp_cpus) {
             warn_report("cpu hotplug feature has been disabled");
         }
-        machine->smp.max_cpus = smp_cpus;
     }
 
     notifier_list_init(&vms->cpuhp_notifiers);
-    possible_cpus = mc->possible_cpu_arch_ids(machine);
     assert(possible_cpus->len == max_cpus);
     for (n = 0; n < possible_cpus->len; n++) {
         Object *cpuobj;
         CPUState *cs;
 
+        if (!vms->cpu_hotplug_enabled && n >= smp_cpus) {
+            break;
+        }
+
         cpuobj = object_new(possible_cpus->cpus[n].type);
         cs = CPU(cpuobj);
 
diff --git a/include/hw/arm/virt.h b/include/hw/arm/virt.h
index 138531f9c1..7a734f07f7 100644
--- a/include/hw/arm/virt.h
+++ b/include/hw/arm/virt.h
@@ -210,10 +210,16 @@ static uint32_t virt_redist_capacity(VirtMachineState *vms, int region)
 static inline int virt_gicv3_redist_region_count(VirtMachineState *vms)
 {
     uint32_t redist0_capacity = virt_redist_capacity(vms, VIRT_GIC_REDIST);
+    MachineState *ms = MACHINE(vms);
+    unsigned int max_cpus = ms->smp.max_cpus;
+
+    if (!vms->cpu_hotplug_enabled) {
+        max_cpus = ms->smp.cpus;
+    }
 
     assert(vms->gic_version != VIRT_GIC_VERSION_2);
 
-    return (MACHINE(vms)->smp.max_cpus > redist0_capacity &&
+    return (max_cpus > redist0_capacity &&
             vms->highmem_redists) ? 2 : 1;
 }
 
-- 
2.27.0