On Mon, 8 Jun 2026 19:07:20 +0200 Eric Auger <[email protected]> wrote:
> On 3/3/26 10:25 AM, Igor Mammedov wrote: > > 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 <[email protected]> > > --- > > 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 <[email protected]> > > + * > > + * 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 <[email protected]> > > + * > > + * 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 <[email protected]> > > + * > > + * 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 */ > you can add a comment that 0xff must be set for following 3 fields as > not a PCI device. > > + 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 */ > it is a bit weird to hardcode the freq while it is passed as parameter. > Why don't you propagate it in the table? > > + /* > > + * Needs to be more than 4min, otherwise Windows 11 won't start > > watchdog. > spec says: > " > The time-out period before the WDT fires is recommended to be at least 5 > minutes and is required to be less than 4,294,967,296 count intervals. > " > where does the 4 min come from? it documents (empirical) lower Windows limit vs recommended one, so later on someone wouldn't step on that same rake. > > + * Set max to limits to arbitrary max 10min and min to 5sec. > > + */ > > + build_append_int_noprefix(table_data, 600 * freq, 4);/* Maximum Count > > */ > spec says this is in count interval and not in ms, no? yep, and that's what it is here (or maybe I misread question) > > + build_append_int_noprefix(table_data, 5 * freq, 4); /* Minimum Count > > */ > same > > + /* > > + * WATCHDOG_ENABLED > and stopped in sleep state? > > + */ > > + 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); > why 0x7? where did you get that mask value from > > in DEN0094E_BSA_1.2.pdf > > "0x000-0x003 WRR Watchdog refresh register. A write to this location > causes the watchdog to refresh and start a new > watch period. A read has no effect and returns 0." > > + build_append_wdat_ins(table_data, WDAT_ACTION_SET_COUNTDOWN_PERIOD, > > + WDAT_INS_WRITE_COUNTDOWN, > > + wor_l, 0, 0xffffffff); > How does the above intrustuction work? How the countdown period is > passed? what does the 0 mean in that case? the countdown period comes from the OS at runtime, not from the WDAT table, the value here is ignored. > > I would rather group instructions on wcs and then instructions using wor > or wrr > > + 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); > reflects the status of WS1 only (and not WS0). Can you explain why this > is what we want? spec says: "Determines if the current boot was caused by the watchdog firing. The boot status is required to be set if the watchdog fired and caused a reboot." WS1 is the event we are after, WS0 is not that by any means. > > + 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) + > this patch is big. You could easily move the add_wathdog + > virt_get_wdt_options() helper in a different patch I'll split off acpi part (wdat table itself) into as a preceding patch (albeit without immediate user ) and remainder in the second patch would use it. Should make it easier to follow. > > + 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); > > { > Thanks > > Eric >
