hw/acpi/ich9: Add periodic and swsmi timer

This patch implements the periodic and the swsmi ICH9 chipset timers. They are
especially useful when prototyping UEFI firmware (e.g. with EDK2's OVMF)
using QEMU.

For backwards compatibility, the compat properties "x-smi-swsmi-timer",
and "x-smi-periodic-timer" are introduced.

Additionally, writes to the SMI_STS register are enabled for the
corresponding two bits using a write mask to make future work easier.

Signed-off-by: Dominic Prinz <git@dprinz.de>
Message-Id: <1d90ea69e01ab71a0f2ced116801dc78e04f4448.1725991505.git.git@dprinz.de>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

5 files changed, 135 insertions, 2 deletions

diff --git a/hw/acpi/ich9.c b/hw/acpi/ich9.c
index 02d8546..c15e5b8 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 +109,18 @@ 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);
+        if (pm->swsmi_timer_enabled) {
+            ich9_pm_update_swsmi_timer(pm, pm->smi_en &
+                                               ICH9_PMIO_SMI_EN_SWSMI_EN);
+        }
+        if (pm->periodic_timer_enabled) {
+            ich9_pm_update_periodic_timer(pm, pm->smi_en &
+                                                  ICH9_PMIO_SMI_EN_PERIODIC_EN);
+        }
+        break;
+    case 4:
+        pm->smi_sts &= ~pm->smi_sts_wmask;
+        pm->smi_sts |= (val & pm->smi_sts_wmask);
         break;
     }
 }
@@ -286,6 +299,8 @@ static void pm_powerdown_req(Notifier *n, void *opaque)
 
 void ich9_pm_init(PCIDevice *lpc_pci, ICH9LPCPMRegs *pm, qemu_irq sci_irq)
 {
+    pm->smi_sts_wmask = 0;
+
     memory_region_init(&pm->io, OBJECT(lpc_pci), "ich9-pm", ICH9_PMIO_SIZE);
     memory_region_set_enabled(&pm->io, false);
     memory_region_add_subregion(pci_address_space_io(lpc_pci),
@@ -305,6 +320,14 @@ 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);
 
+    if (pm->swsmi_timer_enabled) {
+        ich9_pm_swsmi_timer_init(pm);
+    }
+
+    if (pm->periodic_timer_enabled) {
+        ich9_pm_periodic_timer_init(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 0000000..5b1c910
--- /dev/null
+++ b/hw/acpi/ich9_timer.c
@@ -0,0 +1,93 @@
+/*
+ * 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);
+    }
+}
+
+static void ich9_pm_swsmi_timer_expired(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_swsmi_timer_init(ICH9LPCPMRegs *pm)
+{
+    pm->smi_sts_wmask |= ICH9_PMIO_SMI_STS_SWSMI_STS;
+    pm->swsmi_timer =
+        timer_new_ns(QEMU_CLOCK_VIRTUAL, ich9_pm_swsmi_timer_expired, pm);
+}
+
+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);
+    }
+}
+
+static void ich9_pm_periodic_timer_expired(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);
+}
+
+void ich9_pm_periodic_timer_init(ICH9LPCPMRegs *pm)
+{
+    pm->smi_sts_wmask |= ICH9_PMIO_SMI_STS_PERIODIC_STS;
+    pm->periodic_timer =
+        timer_new_ns(QEMU_CLOCK_VIRTUAL, ich9_pm_periodic_timer_expired, pm);
+}
diff --git a/hw/acpi/meson.build b/hw/acpi/meson.build
index fa5c07d..7f8ccc9 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/i386/pc.c b/hw/i386/pc.c
index ba0ff51..8d84c22 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -79,7 +79,10 @@
     { "qemu64-" TYPE_X86_CPU, "model-id", "QEMU Virtual CPU version " v, },\
     { "athlon-" TYPE_X86_CPU, "model-id", "QEMU Virtual CPU version " v, },
 
-GlobalProperty pc_compat_9_1[] = {};
+GlobalProperty pc_compat_9_1[] = {
+    { "ICH9-LPC", "x-smi-swsmi-timer", "off" },
+    { "ICH9-LPC", "x-smi-periodic-timer", "off" },
+};
 const size_t pc_compat_9_1_len = G_N_ELEMENTS(pc_compat_9_1);
 
 GlobalProperty pc_compat_9_0[] = {
diff --git a/hw/isa/lpc_ich9.c b/hw/isa/lpc_ich9.c
index bd727b2..ab17b76 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 +532,15 @@ 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;
 
+    if (lpc->pm.swsmi_timer_enabled) {
+        ich9_pm_update_swsmi_timer(
+            &lpc->pm, lpc->pm.smi_en & ICH9_PMIO_SMI_EN_SWSMI_EN);
+    }
+    if (lpc->pm.periodic_timer_enabled) {
+        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;
@@ -826,6 +836,10 @@ static Property ich9_lpc_properties[] = {
                       ICH9_LPC_SMI_F_CPU_HOTPLUG_BIT, true),
     DEFINE_PROP_BIT64("x-smi-cpu-hotunplug", ICH9LPCState, smi_host_features,
                       ICH9_LPC_SMI_F_CPU_HOT_UNPLUG_BIT, true),
+    DEFINE_PROP_BOOL("x-smi-swsmi-timer", ICH9LPCState,
+                     pm.swsmi_timer_enabled, true),
+    DEFINE_PROP_BOOL("x-smi-periodic-timer", ICH9LPCState,
+                     pm.periodic_timer_enabled, true),
     DEFINE_PROP_END_OF_LIST(),
 };