On Thu, Feb 19, 2026 at 01:17:51PM +0100, Igor Mammedov wrote: > On Wed, 18 Feb 2026 19:08:36 +0000 > Peter Maydell <[email protected]> wrote: > > > On Fri, 6 Feb 2026 at 13:15, Igor Mammedov <[email protected]> wrote: > > > > > > Add SBSA generic watchdog to virt machine type with > > > all necessary wiring for ACPI watchdog. Which includes > > > setting its frequency to 1KHz (max that WDAT is able to handle). > > > > > > Signed-off-by: Igor Mammedov <[email protected]> > > > --- > > > > > diff --git a/hw/arm/virt.c b/hw/arm/virt.c > > > index 390845c503..caf5700ed2 100644 > > > --- a/hw/arm/virt.c > > > +++ b/hw/arm/virt.c > > > @@ -93,6 +93,7 @@ > > > #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[] = { > > > { TYPE_VIRTIO_IOMMU_PCI, "aw-bits", "48" }, > > > @@ -194,6 +195,8 @@ static const MemMapEntry base_memmap[] = { > > > [VIRT_PVTIME] = { 0x090a0000, 0x00010000 }, > > > [VIRT_SECURE_GPIO] = { 0x090b0000, 0x00001000 }, > > > [VIRT_ACPI_PCIHP] = { 0x090c0000, ACPI_PCIHP_SIZE }, > > > + [VIRT_GWDT_REFRESH] = { 0x090d0000, 0x00001000 }, > > > + [VIRT_GWDT_CONTROL] = { 0x090d1000, 0x00001000 }, > > > [VIRT_MMIO] = { 0x0a000000, 0x00000200 }, > > > /* ...repeating for a total of NUM_VIRTIO_TRANSPORTS, each of that > > > size */ > > > [VIRT_PLATFORM_BUS] = { 0x0c000000, 0x02000000 }, > > > @@ -245,12 +248,32 @@ static const int a15irqmap[] = { > > > [VIRT_GPIO] = 7, > > > [VIRT_UART1] = 8, > > > [VIRT_ACPI_GED] = 9, > > > + [VIRT_GWDT_WS0] = 10, > > > [VIRT_MMIO] = 16, /* ...to 16 + NUM_VIRTIO_TRANSPORTS - 1 */ > > > [VIRT_GIC_V2M] = 48, /* ...to 48 + NUM_GICV2M_SPIS - 1 */ > > > [VIRT_SMMU] = 74, /* ...to 74 + NUM_SMMU_IRQS - 1 */ > > > [VIRT_PLATFORM_BUS] = 112, /* ...to 112 + PLATFORM_BUS_NUM_IRQS -1 */ > > > }; > > > > > > +static void create_wdt(const VirtMachineState *vms) > > > +{ > > > + hwaddr rbase = vms->memmap[VIRT_GWDT_REFRESH].base; > > > + hwaddr cbase = vms->memmap[VIRT_GWDT_CONTROL].base; > > > + int irq = vms->irqmap[VIRT_GWDT_WS0]; > > > + DeviceState *dev = qdev_new(TYPE_WDT_SBSA); > > > + SysBusDevice *s = SYS_BUS_DEVICE(dev); > > > + > > > + /* > > > + * Set watchdog tick freq to 1Kz as it's the max WDAT driver > > > + * is able to handle. > > > + */ > > > + qdev_prop_set_uint64(dev, "clock-frequency", 1000 /* 1KHz */); > > > + sysbus_realize_and_unref(s, &error_fatal); > > > + sysbus_mmio_map(s, 0, rbase); > > > + sysbus_mmio_map(s, 1, cbase); > > > + sysbus_connect_irq(s, 0, qdev_get_gpio_in(vms->gic, irq)); > > > +} > > > > Please can you also add support for exposing this device > > in the device tree ? > > It's possible, > but we probably should not enable it if acpi variant was requested, > to avoid confusion on guest side. > > For Windows it doesn't really mater, for linux it does. > on x86 linux guest uses a quirk to disable native iTCO watchdog > in favor of WDAT one if later is present. > I assume quirk is not desirable so we should expose only a preferred > variant. > > > > > > + > > > static void create_randomness(MachineState *ms, const char *node) > > > { > > > struct { > > > @@ -2515,6 +2538,9 @@ static void machvirt_init(MachineState *machine) > > > vms->highmem_ecam &= (!firmware_loaded || aarch64); > > > > > > create_rtc(vms); > > > + if (machine->acpi_watchdog) { > > > + create_wdt(vms); > > > + } > > > > Can we have a command line option name that isn't ACPI > > specific, please? There's nothing inherent to ACPI about > > "I would like a watchdog device". > > that is specifically asking for ACPI flavor being used/configured. > acpi specific option conflates 2 things: > 1. watchdog device creation (of the board choice) with properties tuned > for WDAT usage > 2. how to expose it on firmware level (in this case ACPI WDAT table) > > other option, I've considered was > -device some_wd[,fw=dt|acpi|none] > but then 'fw' is not exactly device property but rather a machine one > (we can 'abuse' it/use as a proxy of cause). > However it doesn't work for boards that have builtin watchdog.
Right, if there was a case where we were already using -device to create the watchdog, then I would suggest having a simple 'wadt=on|off' property as standard for any watchdog wanting that ACPI abstraction wrapper. That could (hypothetically) be the case if we had chosen to add WADT suport backed by i6300esb, eg -device i6300esb,wadt=on|off For cases built-in to the machine type, I'd suggest <type>-wadt=on|off eg for Q35, "-machine q35,itco-wadt=on|off" for virt, '-machine virt,gwdt-wadt=on|off' Q35 is easier as we rely on the guest quirks to disable direct access via both paths. With GWDT we need to decide if gwdt-wadt=on should imply DTB disabled, or if we just expose both & rely on a guest quirk or worst case, need a separate property to toggle DTB too. > I've used device property for x86 Q35 TCO watchdog and > then using -global to enable it as workaround in previous version. > Ugly but doable workaround. It puts a burden on users to learn how > to configure it for each support watchdog/board combo. > It's nightmare to discover/maintain though. > > Hence in this version, I've used a generic machine property approach > that exposes feature in uniform way across boards. > > enum might work, but ... > machine.watchdog = [acpi | what else could we put here???] > > I'm not married to a way how we expose/configure it and will rewrite > it to something that works for majority. > > > thanks > > -- PMM > > > With regards, Daniel -- |: https://berrange.com ~~ https://hachyderm.io/@berrange :| |: https://libvirt.org ~~ https://entangle-photo.org :| |: https://pixelfed.art/berrange ~~ https://fstop138.berrange.com :|
