From 85e8e1ee8560e587845142342f81b218e44cba6a Mon Sep 17 00:00:00 2001
From: Keqian Zhu <zhukeqian1@huawei.com>
Date: Tue, 26 Mar 2024 22:07:33 +0800
Subject: [PATCH] arm/kvm: Set psci smccc filter only with vcpu hotplug

The smccc filter mechanism is supported by newer Linux kernel,
don't try to do it unconditionaly.

Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
---
 hw/arm/virt.c    |  4 +++-
 target/arm/kvm.c | 21 ++++++++++++---------
 2 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index e60f3431f9..38b5d214a1 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -2366,8 +2366,10 @@ static void machvirt_init(MachineState *machine)
     finalize_gic_version(vms);
     if (tcg_enabled() || hvf_enabled() || qtest_enabled() ||
         (vms->gic_version < VIRT_GIC_VERSION_3)) {
-        machine->smp.max_cpus = smp_cpus;
         mc->has_hotpluggable_cpus = false;
+    }
+    if (!mc->has_hotpluggable_cpus) {
+        machine->smp.max_cpus = smp_cpus;
         warn_report("cpu hotplug feature has been disabled");
     }
 
diff --git a/target/arm/kvm.c b/target/arm/kvm.c
index 66caf9e5e7..19783d567f 100644
--- a/target/arm/kvm.c
+++ b/target/arm/kvm.c
@@ -259,6 +259,7 @@ int kvm_arch_get_default_type(MachineState *ms)
 
 int kvm_arch_init(MachineState *ms, KVMState *s)
 {
+    MachineClass *mc = MACHINE_GET_CLASS(ms);
     int ret = 0;
 
     /* For ARM interrupt delivery is always asynchronous,
@@ -316,15 +317,17 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
      * filter in the Host KVM. This is required to support features like
      * virtual CPU Hotplug on ARM platforms.
      */
-    if (kvm_arm_set_smccc_filter(PSCI_0_2_FN64_CPU_ON,
-                                 KVM_SMCCC_FILTER_FWD_TO_USER)) {
-        error_report("CPU On PSCI-to-user-space fwd filter install failed");
-        abort();
-    }
-    if (kvm_arm_set_smccc_filter(PSCI_0_2_FN_CPU_OFF,
-                                 KVM_SMCCC_FILTER_FWD_TO_USER)) {
-        error_report("CPU Off PSCI-to-user-space fwd filter install failed");
-        abort();
+    if (mc->has_hotpluggable_cpus && ms->smp.max_cpus > ms->smp.cpus) {
+        if (kvm_arm_set_smccc_filter(PSCI_0_2_FN64_CPU_ON,
+                                    KVM_SMCCC_FILTER_FWD_TO_USER)) {
+            error_report("CPU On PSCI-to-user-space fwd filter install failed");
+            mc->has_hotpluggable_cpus = false;
+        }
+        if (kvm_arm_set_smccc_filter(PSCI_0_2_FN_CPU_OFF,
+                                    KVM_SMCCC_FILTER_FWD_TO_USER)) {
+            error_report("CPU Off PSCI-to-user-space fwd filter install failed");
+            mc->has_hotpluggable_cpus = false;
+        }
     }
 
     kvm_arm_init_debug(s);
-- 
2.27.0