Hi Igor, On 5/27/26 2:49 PM, Igor Mammedov wrote: > On Tue, 26 May 2026 15:58:08 +0200 > Eric Auger <[email protected]> wrote: > >> Hi Igor, >> >> On 3/3/26 10:25 AM, Igor Mammedov wrote: >>> Allow to use SBSA generic watchdog with virt machine type. >>> (includes conditional generation of corresponding FDT and >>> ACPI GTDT descriptors) >>> >>> Use '-device sbsa_gwdt' to command line to enable it. >> I thank that in general Peter is not a big fan of dynamic instantiation >> of sysbus devices. Don't you have means to instantiate it statically in >> arm virt memory map? > > /me neither > > in previous version there was a machine option to enable the feature > to that was rejected in favor of device. > > in this case for platform -device of sysbus based device, I don't think > we can do better that dynamic sysbus.
sorry I may have missed some previous discussion details. As far as I can read, I understand you could instantiate the wdt in a free MMIO slot, unconfitionnaly just as it is done in hw/arm/sbsa-ref.c. Maybe add a compat to avoid having it by default on older machine types. Then about the type of the integration gtdt or wat, can't you have a device compat? Thanks Eric > > >> >> Eric >>> >>> Tested with Fedora 43: >>> FDT: -M virt,acpi=off -device sbsa_gwdt >>> ACPI: -M virt -device sbsa_gwdt >>> >>> Signed-off-by: Igor Mammedov <[email protected]> >>> --- >>> hw/arm/Kconfig | 1 + >>> hw/arm/virt-acpi-build.c | 33 +++++++++++++++++++++++++++++++-- >>> hw/arm/virt.c | 2 ++ >>> hw/core/sysbus-fdt.c | 32 ++++++++++++++++++++++++++++++++ >>> hw/watchdog/sbsa_gwdt.c | 1 + >>> 5 files changed, 67 insertions(+), 2 deletions(-) >>> >>> diff --git a/hw/arm/Kconfig b/hw/arm/Kconfig >>> index c66c452737..1222efadd1 100644 >>> --- a/hw/arm/Kconfig >>> +++ b/hw/arm/Kconfig >>> @@ -36,6 +36,7 @@ config ARM_VIRT >>> select VIRTIO_MEM_SUPPORTED >>> select ACPI_CXL >>> select ACPI_HMAT >>> + select WDT_SBSA >>> >>> config CUBIEBOARD >>> bool >>> diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c >>> index 719d2f994e..9c14b1d4d5 100644 >>> --- a/hw/arm/virt-acpi-build.c >>> +++ b/hw/arm/virt-acpi-build.c >>> @@ -64,6 +64,7 @@ >>> #include "hw/virtio/virtio-acpi.h" >>> #include "target/arm/cpu.h" >>> #include "target/arm/multiprocessing.h" >>> +#include "hw/watchdog/sbsa_gwdt.h" >>> >>> #define ARM_SPI_BASE 32 >>> >>> @@ -863,6 +864,8 @@ build_gtdt(GArray *table_data, BIOSLinker *linker, >>> VirtMachineState *vms) >>> const uint32_t irqflags = 0; /* Interrupt is Level triggered */ >>> 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); >>> >>> @@ -893,10 +896,15 @@ build_gtdt(GArray *table_data, BIOSLinker *linker, >>> VirtMachineState *vms) >>> build_append_int_noprefix(table_data, irqflags, 4); >>> /* CntReadBase Physical address */ >>> build_append_int_noprefix(table_data, 0xFFFFFFFFFFFFFFFF, 8); >>> + >>> /* Platform Timer Count */ >>> - build_append_int_noprefix(table_data, 0, 4); >>> + build_append_int_noprefix(table_data, wdt ? 1 : 0, 4); >>> /* Platform Timer Offset */ >>> - build_append_int_noprefix(table_data, 0, 4); >>> + 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); >>> + >>> if (vms->ns_el2_virt_timer_irq) { >>> /* Virtual EL2 Timer GSIV */ >>> build_append_int_noprefix(table_data, ARCH_TIMER_NS_EL2_VIRT_IRQ, >>> 4); >>> @@ -906,6 +914,27 @@ build_gtdt(GArray *table_data, BIOSLinker *linker, >>> VirtMachineState *vms) >>> build_append_int_noprefix(table_data, 0, 4); >>> build_append_int_noprefix(table_data, 0, 4); >>> } >>> + >>> + /* 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); >>> + >>> + build_append_int_noprefix(table_data, 1 /* Type: Watchdog GT */, >>> 1); >>> + build_append_int_noprefix(table_data, 28 /* Length */, 2); >>> + build_append_int_noprefix(table_data, 0, 1); /* Reserved */ >>> + /* RefreshFrame Physical Address */ >>> + build_append_int_noprefix(table_data, rbase, 8); >>> + /* WatchdogControlFrame Physical Address */ >>> + build_append_int_noprefix(table_data, cbase, 8); >>> + build_append_int_noprefix(table_data, irq, 4); /* Watchdog Timer >>> GSIV */ >>> + build_append_int_noprefix(table_data, 0, 4); /* Watchdog Timer >>> Flags */ >>> + } >>> acpi_table_end(linker, &table); >>> } >>> >>> diff --git a/hw/arm/virt.c b/hw/arm/virt.c >>> index cab2e21e8a..a87991b591 100644 >>> --- a/hw/arm/virt.c >>> +++ b/hw/arm/virt.c >>> @@ -95,6 +95,7 @@ >>> #include "hw/cxl/cxl.h" >>> #include "hw/cxl/cxl_host.h" >>> #include "qemu/guest-random.h" >>> +#include "hw/watchdog/sbsa_gwdt.h" >>> >>> static GlobalProperty arm_virt_compat_defaults[] = { >>> { TYPE_VIRTIO_IOMMU_PCI, "aw-bits", "48" }, >>> @@ -3474,6 +3475,7 @@ static void virt_machine_class_init(ObjectClass *oc, >>> const void *data) >>> machine_class_allow_dynamic_sysbus_dev(mc, TYPE_RAMFB_DEVICE); >>> machine_class_allow_dynamic_sysbus_dev(mc, TYPE_UEFI_VARS_SYSBUS); >>> machine_class_allow_dynamic_sysbus_dev(mc, TYPE_ARM_SMMUV3); >>> + machine_class_allow_dynamic_sysbus_dev(mc, TYPE_WDT_SBSA); >>> #ifdef CONFIG_TPM >>> machine_class_allow_dynamic_sysbus_dev(mc, TYPE_TPM_TIS_SYSBUS); >>> #endif >>> diff --git a/hw/core/sysbus-fdt.c b/hw/core/sysbus-fdt.c >>> index 89d0c46445..76aa1bc579 100644 >>> --- a/hw/core/sysbus-fdt.c >>> +++ b/hw/core/sysbus-fdt.c >>> @@ -36,6 +36,7 @@ >>> #include "hw/display/ramfb.h" >>> #include "hw/uefi/var-service-api.h" >>> #include "hw/arm/fdt.h" >>> +#include "hw/watchdog/sbsa_gwdt.h" >>> >>> /* >>> * internal struct that contains the information to create dynamic >>> @@ -118,6 +119,36 @@ static int add_uefi_vars_node(SysBusDevice *sbdev, >>> void *opaque) >>> return 0; >>> } >>> >>> +static int add_sbsa_gwdt_node(SysBusDevice *sbdev, void *opaque) >>> +{ >>> + PlatformBusFDTData *data = opaque; >>> + PlatformBusDevice *pbus = data->pbus; >>> + const char *parent_node = data->pbus_node_name; >>> + void *fdt = data->fdt; >>> + uint64_t cbase, rbase; >>> + char *nodename; >>> + int irq; >>> + >>> + cbase = platform_bus_get_mmio_addr(pbus, sbdev, 1); /* control frame >>> */ >>> + rbase = platform_bus_get_mmio_addr(pbus, sbdev, 0); /* refresh frame >>> */ >>> + irq = platform_bus_get_irqn(pbus, sbdev, 0); >>> + >>> + nodename = g_strdup_printf("%s/watchdog@%" PRIx64, parent_node, cbase); >>> + qemu_fdt_add_subnode(fdt, nodename); >>> + >>> + qemu_fdt_setprop_string(fdt, nodename, "compatible", "arm,sbsa-gwdt"); >>> + qemu_fdt_setprop_cells(fdt, nodename, "reg", >>> + cbase, SBSA_GWDT_CMMIO_SIZE, >>> + rbase, SBSA_GWDT_RMMIO_SIZE); >>> + qemu_fdt_setprop_cells(fdt, nodename, "interrupts", >>> + GIC_FDT_IRQ_TYPE_SPI, data->irq_start + irq, >>> + GIC_FDT_IRQ_FLAGS_LEVEL_HI); >>> + qemu_fdt_setprop_cell(fdt, nodename, "timeout-sec", 30); >>> + >>> + g_free(nodename); >>> + return 0; >>> +} >>> + >>> static int no_fdt_node(SysBusDevice *sbdev, void *opaque) >>> { >>> return 0; >>> @@ -140,6 +171,7 @@ static const BindingEntry bindings[] = { >>> TYPE_BINDING(TYPE_ARM_SMMUV3, no_fdt_node), >>> TYPE_BINDING(TYPE_RAMFB_DEVICE, no_fdt_node), >>> TYPE_BINDING(TYPE_UEFI_VARS_SYSBUS, add_uefi_vars_node), >>> + TYPE_BINDING(TYPE_WDT_SBSA, add_sbsa_gwdt_node), >>> TYPE_BINDING("", NULL), /* last element */ >>> }; >>> >>> diff --git a/hw/watchdog/sbsa_gwdt.c b/hw/watchdog/sbsa_gwdt.c >>> index acb970e8b3..c4dd8005b7 100644 >>> --- a/hw/watchdog/sbsa_gwdt.c >>> +++ b/hw/watchdog/sbsa_gwdt.c >>> @@ -285,6 +285,7 @@ static void wdt_sbsa_gwdt_class_init(ObjectClass >>> *klass, const void *data) >>> dc->realize = wdt_sbsa_gwdt_realize; >>> device_class_set_legacy_reset(dc, wdt_sbsa_gwdt_reset); >>> dc->hotpluggable = false; >>> + dc->user_creatable = true; >>> set_bit(DEVICE_CATEGORY_WATCHDOG, dc->categories); >>> dc->vmsd = &vmstate_sbsa_gwdt; >>> dc->desc = "SBSA-compliant generic watchdog device"; >> >
