[PATCH 0/2] x86/cpu: initialize SMM cpu address space for hotplugged cpus

[PATCH 0/2] x86/cpu: initialize SMM cpu address space for hotplugged cpus

[Xiaoyao Li]

(Sorry for being late to post the fixing patch, due to Chinese National
holiday.)

Patch 1 fixes the issue reported by Peter that hotplugged cpu doesn't get
SMM cpu addresspace initialized.

Patch 2 "fixes" the part that was missed when the original patch got
merged.

Xiaoyao Li (2):
  i386/kvm/cpu: Init SMM cpu address space for hotplugged CPUs
  target/i386: Use X86ASIdx_MEM in kvm_init()

 accel/kvm/kvm-all.c        |  2 +-
 hw/i386/x86-common.c       | 11 +++++++++++
 target/i386/kvm/kvm.c      |  6 ++++++
 target/i386/kvm/kvm_i386.h |  1 +
 4 files changed, 19 insertions(+), 1 deletion(-)

-- 
2.43.0

[PATCH 1/2] i386/kvm/cpu: Init SMM cpu address space for hotplugged CPUs

[Xiaoyao Li]

The SMM cpu address space is initialized in a machine_init_done
notifier. It only runs once when QEMU starts up, which leads to the
issue that for any hotplugged CPU after the machine is ready, SMM
cpu address space doesn't get initialized.

Fix the issue by initializing the SMM cpu address space in x86_cpu_plug()
when the cpu is hotplugged.

Fixes: 591f817d819f ("target/i386: Define enum X86ASIdx for x86's address spaces")
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Closes: https://lore.kernel.org/qemu-devel/CAFEAcA_3kkZ+a5rTZGmK8W5K6J7qpYD31HkvjBnxWr-fGT2h_A@mail.gmail.com/
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
---
 hw/i386/x86-common.c       | 11 +++++++++++
 target/i386/kvm/kvm.c      |  6 ++++++
 target/i386/kvm/kvm_i386.h |  1 +
 3 files changed, 18 insertions(+)

diff --git a/hw/i386/x86-common.c b/hw/i386/x86-common.c
index 7512be64d67b..dd6ac3f3b741 100644
--- a/hw/i386/x86-common.c
+++ b/hw/i386/x86-common.c
@@ -183,6 +183,17 @@ void x86_cpu_plug(HotplugHandler *hotplug_dev,
         fw_cfg_modify_i16(x86ms->fw_cfg, FW_CFG_NB_CPUS, x86ms->boot_cpus);
     }
 
+    /*
+     * Non-hotplugged CPUs get their SMM cpu address space initialized in
+     * machine init done notifier: register_smram_listener().
+     *
+     * We need initialize the SMM cpu address space for the hotplugged CPU
+     * specifically.
+     */
+    if (dev->hotplugged && kvm_enabled() && x86_machine_is_smm_enabled(x86ms)) {
+        kvm_smm_cpu_address_space_init(cpu);
+    }
+
     found_cpu = x86_find_cpu_slot(MACHINE(x86ms), cpu->apic_id, NULL);
     found_cpu->cpu = CPU(dev);
 out:
diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index db40caa3412f..c339d8c84434 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -2731,6 +2731,12 @@ static void register_smram_listener(Notifier *n, void *unused)
     }
 }
 
+/* It should only be called in cpu's hotplug callback */
+void kvm_smm_cpu_address_space_init(X86CPU *cpu)
+{
+    cpu_address_space_init(CPU(cpu), X86ASIdx_SMM, "cpu-smm", &smram_as_root);
+}
+
 static void *kvm_msr_energy_thread(void *data)
 {
     KVMState *s = data;
diff --git a/target/i386/kvm/kvm_i386.h b/target/i386/kvm/kvm_i386.h
index 5f83e8850a2b..35017ba07a4a 100644
--- a/target/i386/kvm/kvm_i386.h
+++ b/target/i386/kvm/kvm_i386.h
@@ -74,6 +74,7 @@ uint32_t kvm_x86_build_cpuid(CPUX86State *env, struct kvm_cpuid_entry2 *entries,
                              uint32_t cpuid_i);
 #endif /* CONFIG_KVM */
 
+void kvm_smm_cpu_address_space_init(X86CPU *cpu);
 void kvm_pc_setup_irq_routing(bool pci_enabled);
 
 #endif
-- 
2.43.0

[PATCH 2/2] target/i386: Use X86ASIdx_MEM in kvm_init()

[Xiaoyao Li]

When the patch introduces 'enum X86ADIdx'[0] got merged, it somehow
missed the change to replace as id 0 with X86ASIdx_MEM in kvm_init().

Change the leftover in kvm_init() to make the usage consistent.

[0] https://lore.kernel.org/qemu-devel/20250730095253.1833411-3-xiaoyao.li@intel.com/

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
---
 accel/kvm/kvm-all.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 58802f7c3cc1..3030c47d55b1 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -2800,7 +2800,7 @@ static int kvm_init(AccelState *as, MachineState *ms)
     s->memory_listener.listener.coalesced_io_del = kvm_uncoalesce_mmio_region;
 
     kvm_memory_listener_register(s, &s->memory_listener,
-                                 &address_space_memory, 0, "kvm-memory");
+                                 &address_space_memory, X86ASIdx_MEM, "kvm-memory");
     memory_listener_register(&kvm_io_listener,
                              &address_space_io);
 
-- 
2.43.0