diff --git a/hw/acpi/ich9.c b/hw/acpi/ich9.c
index 02d8546bd3..97d645b750 100644
--- a/hw/acpi/ich9.c
+++ b/hw/acpi/ich9.c
@@ -35,6 +35,7 @@
 #include "sysemu/runstate.h"
 #include "hw/acpi/acpi.h"
 #include "hw/acpi/ich9_tco.h"
+#include "hw/acpi/ich9_timer.h"
 
 #include "hw/southbridge/ich9.h"
 #include "hw/mem/pc-dimm.h"
@@ -108,6 +109,16 @@ static void ich9_smi_writel(void *opaque, hwaddr addr, uint64_t val,
         }
         pm->smi_en &= ~pm->smi_en_wmask;
         pm->smi_en |= (val & pm->smi_en_wmask);
+        ich9_pm_update_swsmi_timer(pm, pm->smi_en &
+                                           ICH9_PMIO_SMI_EN_SWSMI_EN);
+        ich9_pm_update_periodic_timer(pm, pm->smi_en &
+                                              ICH9_PMIO_SMI_EN_PERIODIC_EN);
+        break;
+    case 4:
+        pm->smi_sts &= ~(ICH9_PMIO_SMI_STS_SWSMI_STS |
+                         ICH9_PMIO_SMI_STS_PERIODIC_STS);
+        pm->smi_sts |= val & (ICH9_PMIO_SMI_STS_SWSMI_STS |
+                              ICH9_PMIO_SMI_STS_PERIODIC_STS);
         break;
     }
 }
@@ -305,6 +316,10 @@ void ich9_pm_init(PCIDevice *lpc_pci, ICH9LPCPMRegs *pm, qemu_irq sci_irq)
                           "acpi-smi", 8);
     memory_region_add_subregion(&pm->io, ICH9_PMIO_SMI_EN, &pm->io_smi);
 
+    pm->swsmi_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, ich9_swsmi_timer, pm);
+
+    pm->periodic_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, ich9_periodic_timer, pm);
+
     if (pm->enable_tco) {
         acpi_pm_tco_init(&pm->tco_regs, &pm->io);
     }
diff --git a/hw/acpi/ich9_timer.c b/hw/acpi/ich9_timer.c
new file mode 100644
index 0000000000..2e6b68f0fb
--- /dev/null
+++ b/hw/acpi/ich9_timer.c
@@ -0,0 +1,79 @@
+/*
+ * QEMU ICH9 Timer emulation
+ *
+ * Copyright (c) 2024 Dominic Prinz <git@dprinz.de>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "hw/core/cpu.h"
+#include "hw/pci/pci.h"
+#include "hw/southbridge/ich9.h"
+#include "qemu/timer.h"
+
+#include "hw/acpi/ich9_timer.h"
+
+void ich9_pm_update_swsmi_timer(ICH9LPCPMRegs *pm, bool enable)
+{
+    uint16_t swsmi_rate_sel;
+    int64_t expire_time;
+    ICH9LPCState *lpc;
+
+    if (enable) {
+        lpc = container_of(pm, ICH9LPCState, pm);
+        swsmi_rate_sel =
+            (pci_get_word(lpc->d.config + ICH9_LPC_GEN_PMCON_3) & 0xc0) >> 6;
+
+        if (swsmi_rate_sel == 0) {
+            expire_time = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + 1500000LL;
+        } else {
+            expire_time = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
+                          8 * (1 << swsmi_rate_sel) * 1000000LL;
+        }
+
+        timer_mod(pm->swsmi_timer, expire_time);
+    } else {
+        timer_del(pm->swsmi_timer);
+    }
+}
+
+void ich9_swsmi_timer(void *opaque)
+{
+    ICH9LPCPMRegs *pm = opaque;
+
+    pm->smi_sts |= ICH9_PMIO_SMI_STS_SWSMI_STS;
+    ich9_generate_smi();
+
+    ich9_pm_update_swsmi_timer(pm, pm->smi_en & ICH9_PMIO_SMI_EN_SWSMI_EN);
+}
+
+void ich9_pm_update_periodic_timer(ICH9LPCPMRegs *pm, bool enable)
+{
+    uint16_t per_smi_sel;
+    int64_t expire_time;
+    ICH9LPCState *lpc;
+
+    if (enable) {
+        lpc = container_of(pm, ICH9LPCState, pm);
+        per_smi_sel = pci_get_word(lpc->d.config + ICH9_LPC_GEN_PMCON_1) & 3;
+        expire_time = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
+                      8 * (1 << (3 - per_smi_sel)) * NANOSECONDS_PER_SECOND;
+
+        timer_mod(pm->periodic_timer, expire_time);
+    } else {
+        timer_del(pm->periodic_timer);
+    }
+}
+
+void ich9_periodic_timer(void *opaque)
+{
+    ICH9LPCPMRegs *pm = opaque;
+
+    pm->smi_sts = ICH9_PMIO_SMI_STS_PERIODIC_STS;
+    ich9_generate_smi();
+
+    ich9_pm_update_periodic_timer(pm,
+                                  pm->smi_en & ICH9_PMIO_SMI_EN_PERIODIC_EN);
+}
diff --git a/hw/acpi/meson.build b/hw/acpi/meson.build
index fa5c07db90..7f8ccc9b7a 100644
--- a/hw/acpi/meson.build
+++ b/hw/acpi/meson.build
@@ -24,7 +24,7 @@ acpi_ss.add(when: 'CONFIG_ACPI_PCI_BRIDGE', if_true: files('pci-bridge.c'))
 acpi_ss.add(when: 'CONFIG_ACPI_PCIHP', if_true: files('pcihp.c'))
 acpi_ss.add(when: 'CONFIG_ACPI_PCIHP', if_false: files('acpi-pci-hotplug-stub.c'))
 acpi_ss.add(when: 'CONFIG_ACPI_VIOT', if_true: files('viot.c'))
-acpi_ss.add(when: 'CONFIG_ACPI_ICH9', if_true: files('ich9.c', 'ich9_tco.c'))
+acpi_ss.add(when: 'CONFIG_ACPI_ICH9', if_true: files('ich9.c', 'ich9_tco.c', 'ich9_timer.c'))
 acpi_ss.add(when: 'CONFIG_ACPI_ERST', if_true: files('erst.c'))
 acpi_ss.add(when: 'CONFIG_IPMI', if_true: files('ipmi.c'), if_false: files('ipmi-stub.c'))
 acpi_ss.add(when: 'CONFIG_PC', if_false: files('acpi-x86-stub.c'))
diff --git a/hw/isa/lpc_ich9.c b/hw/isa/lpc_ich9.c
index bd727b2320..56daeeedbf 100644
--- a/hw/isa/lpc_ich9.c
+++ b/hw/isa/lpc_ich9.c
@@ -43,6 +43,7 @@
 #include "hw/southbridge/ich9.h"
 #include "hw/acpi/acpi.h"
 #include "hw/acpi/ich9.h"
+#include "hw/acpi/ich9_timer.h"
 #include "hw/pci/pci_bus.h"
 #include "hw/qdev-properties.h"
 #include "sysemu/runstate.h"
@@ -531,6 +532,11 @@ ich9_lpc_pmcon_update(ICH9LPCState *lpc)
     uint16_t gen_pmcon_1 = pci_get_word(lpc->d.config + ICH9_LPC_GEN_PMCON_1);
     uint16_t wmask;
 
+    ich9_pm_update_swsmi_timer(&lpc->pm, lpc->pm.smi_en &
+                                             ICH9_PMIO_SMI_EN_SWSMI_EN);
+    ich9_pm_update_periodic_timer(&lpc->pm, lpc->pm.smi_en &
+                                                ICH9_PMIO_SMI_EN_PERIODIC_EN);
+
     if (gen_pmcon_1 & ICH9_LPC_GEN_PMCON_1_SMI_LOCK) {
         wmask = pci_get_word(lpc->d.wmask + ICH9_LPC_GEN_PMCON_1);
         wmask &= ~ICH9_LPC_GEN_PMCON_1_SMI_LOCK;
diff --git a/include/hw/acpi/ich9.h b/include/hw/acpi/ich9.h
index 2faf7f0cae..940a3d795f 100644
--- a/include/hw/acpi/ich9.h
+++ b/include/hw/acpi/ich9.h
@@ -68,6 +68,9 @@ typedef struct ICH9LPCPMRegs {
     bool smm_compat;
     bool enable_tco;
     TCOIORegs tco_regs;
+
+    QEMUTimer *swsmi_timer;
+    QEMUTimer *periodic_timer;
 } ICH9LPCPMRegs;
 
 #define ACPI_PM_PROP_TCO_ENABLED "enable_tco"
diff --git a/include/hw/acpi/ich9_timer.h b/include/hw/acpi/ich9_timer.h
new file mode 100644
index 0000000000..e48f9918d8
--- /dev/null
+++ b/include/hw/acpi/ich9_timer.h
@@ -0,0 +1,23 @@
+/*
+ * QEMU ICH9 Timer emulation
+ *
+ * Copyright (c) 2024 Dominic Prinz <git@dprinz.de>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#ifndef HW_ACPI_ICH9_TIMER_H
+#define HW_ACPI_ICH9_TIMER_H
+
+#include "hw/acpi/ich9.h"
+
+void ich9_pm_update_swsmi_timer(ICH9LPCPMRegs *pm, bool enable);
+
+void ich9_swsmi_timer(void *opaque);
+
+void ich9_pm_update_periodic_timer(ICH9LPCPMRegs *pm, bool enable);
+
+void ich9_periodic_timer(void *opaque);
+
+#endif
diff --git a/include/hw/southbridge/ich9.h b/include/hw/southbridge/ich9.h
index fd01649d04..6c60017024 100644
--- a/include/hw/southbridge/ich9.h
+++ b/include/hw/southbridge/ich9.h
@@ -196,8 +196,12 @@ struct ICH9LPCState {
 #define ICH9_PMIO_GPE0_LEN                      16
 #define ICH9_PMIO_SMI_EN                        0x30
 #define ICH9_PMIO_SMI_EN_APMC_EN                (1 << 5)
+#define ICH9_PMIO_SMI_EN_SWSMI_EN               (1 << 6)
 #define ICH9_PMIO_SMI_EN_TCO_EN                 (1 << 13)
+#define ICH9_PMIO_SMI_EN_PERIODIC_EN            (1 << 14)
 #define ICH9_PMIO_SMI_STS                       0x34
+#define ICH9_PMIO_SMI_STS_SWSMI_STS             (1 << 6)
+#define ICH9_PMIO_SMI_STS_PERIODIC_STS          (1 << 14)
 #define ICH9_PMIO_TCO_RLD                       0x60
 #define ICH9_PMIO_TCO_LEN                       32
 
