And generate WDAT table tailored for sbsa_gwdt and disable
watchdog entry in GTDT ACPI table if WDAT is enabled,
since they are mutualy exclusive due to different
timer resolution of sbsa_gwdt.
To enable use "-device sbsa-gwdt,wdat=on" option
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
---
include/hw/acpi/wdat-gwdt.h | 19 ++++++++
hw/acpi/meson.build | 2 +
hw/acpi/wdat-gwdt-stub.c | 16 +++++++
hw/acpi/wdat-gwdt.c | 92 +++++++++++++++++++++++++++++++++++++
hw/arm/virt-acpi-build.c | 58 +++++++++++++++++------
5 files changed, 172 insertions(+), 15 deletions(-)
create mode 100644 include/hw/acpi/wdat-gwdt.h
create mode 100644 hw/acpi/wdat-gwdt-stub.c
create mode 100644 hw/acpi/wdat-gwdt.c
diff --git a/include/hw/acpi/wdat-gwdt.h b/include/hw/acpi/wdat-gwdt.h
new file mode 100644
index 0000000000..42339e031e
--- /dev/null
+++ b/include/hw/acpi/wdat-gwdt.h
@@ -0,0 +1,19 @@
+/*
+ * GWDT Watchdog Action Table (WDAT) definition
+ *
+ * Copyright Red Hat, Inc. 2026
+ * Author(s): Igor Mammedov <imammedo@redhat.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+#ifndef QEMU_HW_ACPI_WDAT_GWDT_H
+#define QEMU_HW_ACPI_WDAT_GWDT_H
+
+#include "hw/acpi/aml-build.h"
+#include "hw/watchdog/sbsa_gwdt.h"
+
+void build_gwdt_wdat(GArray *table_data, BIOSLinker *linker, const char *oem_id,
+ const char *oem_table_id, uint64_t rbase, uint64_t cbase,
+ uint64_t freq);
+
+#endif /* QEMU_HW_ACPI_WDAT_GWDT_H */
diff --git a/hw/acpi/meson.build b/hw/acpi/meson.build
index 22290ca835..189bbb0257 100644
--- a/hw/acpi/meson.build
+++ b/hw/acpi/meson.build
@@ -28,12 +28,14 @@ acpi_ss.add(when: 'CONFIG_ACPI_ICH9', if_true: files('ich9.c', 'ich9_tco.c', 'ic
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'))
+acpi_ss.add(when: 'CONFIG_WDT_SBSA', if_true: files('wdat-gwdt.c'))
if have_tpm
acpi_ss.add(files('tpm.c'))
endif
system_ss.add(when: 'CONFIG_ACPI', if_false: files('acpi-stub.c', 'aml-build-stub.c', 'ghes-stub.c', 'acpi_interface.c'))
system_ss.add(when: 'CONFIG_ACPI_PCI_BRIDGE', if_false: files('pci-bridge-stub.c'))
system_ss.add(when: 'CONFIG_ACPI_ICH9', if_false: files('wdat-ich9-stub.c'))
+system_ss.add(when: 'CONFIG_WDT_SBSA', if_false: files('wdat-gwdt-stub.c'))
system_ss.add_all(when: 'CONFIG_ACPI', if_true: acpi_ss)
system_ss.add(when: 'CONFIG_GHES_CPER', if_true: files('ghes_cper.c'))
system_ss.add(when: 'CONFIG_GHES_CPER', if_false: files('ghes_cper_stub.c'))
diff --git a/hw/acpi/wdat-gwdt-stub.c b/hw/acpi/wdat-gwdt-stub.c
new file mode 100644
index 0000000000..4d43783f70
--- /dev/null
+++ b/hw/acpi/wdat-gwdt-stub.c
@@ -0,0 +1,16 @@
+/*
+ * Copyright Red Hat, Inc. 2026
+ * Author(s): Igor Mammedov <imammedo@redhat.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "hw/acpi/wdat-gwdt.h"
+
+void build_gwdt_wdat(GArray *table_data, BIOSLinker *linker, const char *oem_id,
+ const char *oem_table_id, uint64_t rbase, uint64_t cbase,
+ uint64_t freq)
+{
+ g_assert_not_reached();
+}
diff --git a/hw/acpi/wdat-gwdt.c b/hw/acpi/wdat-gwdt.c
new file mode 100644
index 0000000000..226ba3f01e
--- /dev/null
+++ b/hw/acpi/wdat-gwdt.c
@@ -0,0 +1,92 @@
+/*
+ * SBSA GWDT Watchdog Action Table (WDAT)
+ *
+ * Copyright Red Hat, Inc. 2026
+ * Author(s): Igor Mammedov <imammedo@redhat.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "hw/acpi/aml-build.h"
+#include "hw/acpi/wdat-gwdt.h"
+#include "hw/acpi/wdat.h"
+#include "hw/watchdog/sbsa_gwdt.h"
+
+#define GWDT_REG(base, reg_offset, reg_width) { \
+ .space_id = AML_AS_SYSTEM_MEMORY, \
+ .address = base + reg_offset, .bit_width = reg_width, \
+ .access_width = AML_DWORD_ACC };
+
+/*
+ * "Hardware Watchdog Timers Design Specification"
+ * https://uefi.org/acpi 'Watchdog Action Table (WDAT)'
+ */
+void build_gwdt_wdat(GArray *table_data, BIOSLinker *linker, const char *oem_id,
+ const char *oem_table_id, uint64_t rbase, uint64_t cbase,
+ uint64_t freq)
+{
+ AcpiTable table = { .sig = "WDAT", .rev = 1, .oem_id = oem_id,
+ .oem_table_id = oem_table_id };
+
+ struct AcpiGenericAddress wrr = GWDT_REG(rbase, 0x0, 32);
+ struct AcpiGenericAddress wor_l = GWDT_REG(cbase, SBSA_GWDT_WOR, 32);
+ struct AcpiGenericAddress wcs = GWDT_REG(cbase, SBSA_GWDT_WCS, 32);
+
+ acpi_table_begin(&table, table_data);
+ build_append_int_noprefix(table_data, 0x20, 4); /* Watchdog Header Length */
+ build_append_int_noprefix(table_data, 0xff, 2); /* PCI Segment */
+ build_append_int_noprefix(table_data, 0xff, 1); /* PCI Bus Number */
+ build_append_int_noprefix(table_data, 0xff, 1); /* PCI Device Number */
+ build_append_int_noprefix(table_data, 0xff, 1); /* PCI Function Number */
+ build_append_int_noprefix(table_data, 0, 3); /* Reserved */
+ /*
+ * WDAT spec suports only 1KHz or more coarse watchdog timer,
+ * Set resolution to minimum supported 1ms.
+ * Before starting watchdog Windows set countdown value to 5min.
+ */
+ g_assert(freq <= 1000);
+ build_append_int_noprefix(table_data, 1, 4);/* Timer Period, ms */
+ /*
+ * Needs to be more than 4min, otherwise Windows 11 won't start watchdog.
+ * Set max to limits to arbitrary max 10min and min to 5sec.
+ */
+ build_append_int_noprefix(table_data, 600 * freq, 4);/* Maximum Count */
+ build_append_int_noprefix(table_data, 5 * freq, 4); /* Minimum Count */
+ /*
+ * WATCHDOG_ENABLED
+ */
+ build_append_int_noprefix(table_data, 0x81, 1); /* Watchdog Flags */
+ build_append_int_noprefix(table_data, 0, 3); /* Reserved */
+ /*
+ * watchdog instruction entries
+ */
+ build_append_int_noprefix(table_data, 8, 4);
+ /* Action table */
+ build_append_wdat_ins(table_data, WDAT_ACTION_QUERY_RUNNING_STATE,
+ WDAT_INS_READ_VALUE,
+ wcs, 0x1, 0x1);
+ build_append_wdat_ins(table_data, WDAT_ACTION_RESET,
+ WDAT_INS_WRITE_VALUE,
+ wrr, 0x1, 0x7);
+ build_append_wdat_ins(table_data, WDAT_ACTION_SET_COUNTDOWN_PERIOD,
+ WDAT_INS_WRITE_COUNTDOWN,
+ wor_l, 0, 0xffffffff);
+ build_append_wdat_ins(table_data, WDAT_ACTION_SET_RUNNING_STATE,
+ WDAT_INS_WRITE_VALUE | WDAT_INS_PRESERVE_REGISTER,
+ wcs, 1, 0x00000001);
+ build_append_wdat_ins(table_data, WDAT_ACTION_QUERY_STOPPED_STATE,
+ WDAT_INS_READ_VALUE,
+ wcs, 0x0, 0x00000001);
+ build_append_wdat_ins(table_data, WDAT_ACTION_SET_STOPPED_STATE,
+ WDAT_INS_WRITE_VALUE | WDAT_INS_PRESERVE_REGISTER,
+ wcs, 0x0, 0x00000001);
+ build_append_wdat_ins(table_data, WDAT_ACTION_QUERY_WATCHDOG_STATUS,
+ WDAT_INS_READ_VALUE,
+ wcs, 0x4, 0x00000004);
+ build_append_wdat_ins(table_data, WDAT_ACTION_SET_WATCHDOG_STATUS,
+ WDAT_INS_WRITE_VALUE | WDAT_INS_PRESERVE_REGISTER,
+ wrr, 0x4, 0x4);
+
+ acpi_table_end(linker, &table);
+}
diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
index 9c14b1d4d5..e9670b1a2b 100644
--- a/hw/arm/virt-acpi-build.c
+++ b/hw/arm/virt-acpi-build.c
@@ -65,6 +65,7 @@
#include "target/arm/cpu.h"
#include "target/arm/multiprocessing.h"
#include "hw/watchdog/sbsa_gwdt.h"
+#include "hw/acpi/wdat-gwdt.h"
#define ARM_SPI_BASE 32
@@ -849,12 +850,25 @@ build_srat(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
acpi_table_end(linker, &table);
}
+static void virt_get_wdt_options(VirtMachineState *vms, Object *wdt,
+ hwaddr *rbase, hwaddr *cbase, int *irq)
+{
+ PlatformBusDevice *pbus = PLATFORM_BUS_DEVICE(vms->platform_bus_dev);
+ SysBusDevice *sd = SYS_BUS_DEVICE(wdt);
+ hwaddr mmio_base = vms->memmap[VIRT_PLATFORM_BUS].base;
+ *rbase = mmio_base + platform_bus_get_mmio_addr(pbus, sd, 0);
+ *cbase = mmio_base + platform_bus_get_mmio_addr(pbus, sd, 1);
+ *irq = ARM_SPI_BASE + vms->irqmap[VIRT_PLATFORM_BUS] +
+ platform_bus_get_irqn(pbus, sd, 0);
+}
+
/*
* ACPI spec, Revision 6.5
* 5.2.25 Generic Timer Description Table (GTDT)
*/
static void
-build_gtdt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
+build_gtdt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms,
+ Object *wdt, bool add_watchdog)
{
/*
* Table 5-117 Flag Definitions
@@ -865,7 +879,6 @@ build_gtdt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
AcpiTable table = { .sig = "GTDT", .rev = 3, .oem_id = vms->oem_id,
.oem_table_id = vms->oem_table_id };
uint32_t gtdt_start = table_data->len;
- Object *wdt = object_resolve_type_unambiguous(TYPE_WDT_SBSA, NULL);
acpi_table_begin(&table, table_data);
@@ -898,12 +911,12 @@ build_gtdt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
build_append_int_noprefix(table_data, 0xFFFFFFFFFFFFFFFF, 8);
/* Platform Timer Count */
- build_append_int_noprefix(table_data, wdt ? 1 : 0, 4);
+ build_append_int_noprefix(table_data, add_watchdog ? 1 : 0, 4);
/* Platform Timer Offset */
build_append_int_noprefix(table_data,
- wdt ? (table_data->len - gtdt_start) +
- 4 + 4 + 4 /* len of this & following 2 fields to skip */
- : 0, 4);
+ add_watchdog ? (table_data->len - gtdt_start) +
+ 4 + 4 + 4 /* len of this & following 2 fields to skip */
+ : 0, 4);
if (vms->ns_el2_virt_timer_irq) {
/* Virtual EL2 Timer GSIV */
@@ -916,14 +929,10 @@ build_gtdt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
}
/* ACPI 6.5 spec: 5.2.25.2 ARM Generic Watchdog Structure (Table 5-124) */
- if (wdt) {
- PlatformBusDevice *pbus = PLATFORM_BUS_DEVICE(vms->platform_bus_dev);
- SysBusDevice *sd = SYS_BUS_DEVICE(wdt);
- hwaddr mmio_base = vms->memmap[VIRT_PLATFORM_BUS].base;
- hwaddr rbase = mmio_base + platform_bus_get_mmio_addr(pbus, sd, 0);
- hwaddr cbase = mmio_base + platform_bus_get_mmio_addr(pbus, sd, 1);
- int irq = ARM_SPI_BASE + vms->irqmap[VIRT_PLATFORM_BUS] +
- platform_bus_get_irqn(pbus, sd, 0);
+ if (add_watchdog) {
+ int irq;
+ hwaddr rbase, cbase;
+ virt_get_wdt_options(vms, wdt, &rbase, &cbase, &irq);
build_append_int_noprefix(table_data, 1 /* Type: Watchdog GT */, 1);
build_append_int_noprefix(table_data, 28 /* Length */, 2);
@@ -1282,8 +1291,14 @@ void virt_acpi_build(VirtMachineState *vms, AcpiBuildTables *tables)
VirtMachineClass *vmc = VIRT_MACHINE_GET_CLASS(vms);
GArray *table_offsets;
unsigned dsdt, xsdt;
+ bool has_wdat = false;
GArray *tables_blob = tables->table_data;
MachineState *ms = MACHINE(vms);
+ Object *wdt = object_resolve_type_unambiguous(TYPE_WDT_SBSA, NULL);
+
+ if (wdt) {
+ has_wdat = object_property_get_bool(wdt, "wdat", &error_abort);
+ }
table_offsets = g_array_new(false, true /* clear */,
sizeof(uint32_t));
@@ -1303,6 +1318,19 @@ void virt_acpi_build(VirtMachineState *vms, AcpiBuildTables *tables)
acpi_add_table(table_offsets, tables_blob);
build_madt(tables_blob, tables->linker, vms);
+ acpi_add_table(table_offsets, tables_blob);
+ if (wdt && has_wdat) {
+ int irq;
+ hwaddr rbase, cbase;
+ uint64_t freq = object_property_get_uint(wdt, "clock-frequency",
+ &error_abort);
+ virt_get_wdt_options(vms, wdt, &rbase, &cbase, &irq);
+
+ build_gwdt_wdat(tables_blob, tables->linker,
+ vms->oem_id, vms->oem_table_id,
+ rbase, cbase, freq);
+ }
+
if (!vmc->no_cpu_topology) {
acpi_add_table(table_offsets, tables_blob);
build_pptt(tables_blob, tables->linker, ms,
@@ -1310,7 +1338,7 @@ void virt_acpi_build(VirtMachineState *vms, AcpiBuildTables *tables)
}
acpi_add_table(table_offsets, tables_blob);
- build_gtdt(tables_blob, tables->linker, vms);
+ build_gtdt(tables_blob, tables->linker, vms, wdt, wdt && !has_wdat);
acpi_add_table(table_offsets, tables_blob);
{
--
2.47.3