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[80.230.25.45]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4601f35f2e6sm4909136f8f.32.2026.06.02.23.17.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 02 Jun 2026 23:17:03 -0700 (PDT) Date: Wed, 3 Jun 2026 02:17:00 -0400 From: "Michael S. Tsirkin" To: Igor Mammedov Cc: qemu-devel@nongnu.org, anisinha@redhat.com, pbonzini@redhat.com, peter.maydell@linaro.org, shannon.zhaosl@gmail.com, philmd@linaro.org, zhao1.liu@intel.com, rad@semihalf.com, leif.lindholm@oss.qualcomm.com, qemu-arm@nongnu.org Subject: Re: [PATCH v2 00/21] Introduce ACPI watchdog for Q35 and arm/virt boards Message-ID: <20260603021642-mutt-send-email-mst@kernel.org> References: <20260303092532.2410177-1-imammedo@redhat.com> MIME-Version: 1.0 In-Reply-To: <20260303092532.2410177-1-imammedo@redhat.com> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: arKUztY2GOm4gj1dq3J4KouK8fBmSsGJAhoxC9-NiXs_1780467424 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=170.10.133.124; envelope-from=mst@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -24 X-Spam_score: -2.5 X-Spam_bar: -- X-Spam_report: (-2.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.445, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-arm@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-arm-bounces+qemu-arm=archiver.kernel.org@nongnu.org Sender: qemu-arm-bounces+qemu-arm=archiver.kernel.org@nongnu.org On Tue, Mar 03, 2026 at 10:25:11AM +0100, Igor Mammedov wrote: > Changelog: > v2: > * ditch generic '-machine acpi-watchdog' option in favor of > board specific variants: > x86/q35: -machine wdat={on|off} > arm/virt: -device sbsa_gwdt,wdat={on|off} > * arm/virt: add FDT and GTDT ACPI entries for GWDT when it's present > and hide GDTD one when WDAT is enabled. > * arm/virt: add test case for GTDT > * [18-21] optional GWDT cleanup/fixes in handling WCV register update, > make QEMU behave according to spec (at least the way I read it and > it appears MS also read it that way). It fixes Windows 11 reboots when > GWDT is present (without WDAT). With that fixed it's up to MS to fix > their driver to set sane timeout as with the current one wdatchdog > will never trigger. I picked the x86 patches for now. > Windows doesn't ship built-in TCO watchdog driver, and users are > forced to install vendor specific driver(s) if such exists. > However the OS provides a generic watchdog driver that uses > ACPI WDAT table [1] to abstract actual hardware behind it. > The same applies to ARM version of Windows. > > This series adds > * WDAT table tailored for TCO watchdog that Q35 already > has as part of ICH9 chipset and a knob to enable it. > * SBSA GWDT to arm/virt machine with WDAT table tailored > for it and necessary tweaks to GWDT to make usable > with WDAT driver. > * in addition to WDAT, it also adds native variant > with GWDT described in FDT and DTDT > (broken on Windows/works on linux). > > Guest OS WDAT support is present since Windows Vista and Linux since 2016[2]. > > One can test it launching VM with following options: > * x86: > -machine q35,wdat=on > * arm/virt: > -device sbsa_gwdt,wdat=on > > to trace access to TCO registers one can add to CLI: > -trace "tco_*" > to trace access to GWDT registers one can add to CLI: > -trace "sbsa_gwdt*" > > To verify that guest uses WDAT (both Windows and Linux would use it if present), > * on linux make sure that watchdog service is configured/enabled > (use wdctl to check what watchdog device is in use) and then > trigger kernel panic with command: > echo c > /proc/sysrq-trigger > * on Windows kill svchost process, running cmd in admin mode: > taskkill /f /im svchost.exe > > Tested with WS2025 & RHEL9.6 & Fedora 43 (aarch64) > > git tree at: https://gitlab.com/imammedo/qemu/-/commits/gwdt_v2 > > 1) http://msdn.microsoft.com/en-us/windows/hardware/gg463320.aspx > 2) https://lwn.net/Articles/700524/ > > PS: > previous revision: > https://patchew.org/QEMU/20260206131438.1857182-1-imammedo@redhat.com/ > > Igor Mammedov (21): > acpi: add API to build WDAT instructions > x86: q35: add 'wdat' property > x86: q35: generate WDAT ACPI table > tests: acpi: x86/q35: whitelist new WDAT table > tests: acpi: x86/q35: add WDAT table test case > tests: acpi: x86/q35: update expected WDAT blob > arm: sbsa_gwdt: fixup default "clock-frequency" > arm: add tracing events to sbsa_gwdt > arm: virt: create sbsa_gwdt watchdog > arm: sbsa_gwdt: add 'wdat' option > arm: virt: add support for WDAT based watchdog > tests: acpi: arm/virt: whitelist new WDAT table > tests: acpi: arm/virt: add WDAT table test case > tests: acpi: arm/virt: update expected WDAT blob > tests: acpi: arm/virt: whitelist GTDT table > tests: acpi: arm/virt: add GTDT watchdog table test case > tests: acpi: arm/virt: update expected GTDT blob > sbsa_gwdt: reduce code ident > sbsa_gwdt: move all foo_REFRESH logic under REFRESH condition > sbsa_gwdt: reschedule timer on direct WCV load > sbsa_gwdt: limit compare_value to INT64_MAX > > include/hw/acpi/wdat-gwdt.h | 19 ++++ > include/hw/acpi/wdat-ich9.h | 15 ++++ > include/hw/acpi/wdat.h | 118 +++++++++++++++++++++++++ > include/hw/i386/pc.h | 1 + > include/hw/watchdog/sbsa_gwdt.h | 1 + > hw/acpi/aml-build.c | 14 +++ > hw/acpi/meson.build | 5 +- > hw/acpi/wdat-gwdt-stub.c | 16 ++++ > hw/acpi/wdat-gwdt.c | 92 +++++++++++++++++++ > hw/acpi/wdat-ich9-stub.c | 15 ++++ > hw/acpi/wdat-ich9.c | 90 +++++++++++++++++++ > hw/arm/Kconfig | 1 + > hw/arm/virt-acpi-build.c | 65 +++++++++++++- > hw/arm/virt.c | 2 + > hw/core/sysbus-fdt.c | 32 +++++++ > hw/i386/acpi-build.c | 12 +++ > hw/i386/pc_q35.c | 18 ++++ > hw/watchdog/sbsa_gwdt.c | 65 +++++++++----- > hw/watchdog/trace-events | 9 ++ > tests/data/acpi/aarch64/virt/GTDT.gwdt | Bin 0 -> 132 bytes > tests/data/acpi/aarch64/virt/WDAT.wdat | Bin 0 -> 260 bytes > tests/data/acpi/x86/q35/WDAT.wdat | Bin 0 -> 308 bytes > tests/qtest/bios-tables-test.c | 54 +++++++++++ > 23 files changed, 618 insertions(+), 26 deletions(-) > create mode 100644 include/hw/acpi/wdat-gwdt.h > create mode 100644 include/hw/acpi/wdat-ich9.h > create mode 100644 include/hw/acpi/wdat.h > create mode 100644 hw/acpi/wdat-gwdt-stub.c > create mode 100644 hw/acpi/wdat-gwdt.c > create mode 100644 hw/acpi/wdat-ich9-stub.c > create mode 100644 hw/acpi/wdat-ich9.c > create mode 100644 tests/data/acpi/aarch64/virt/GTDT.gwdt > create mode 100644 tests/data/acpi/aarch64/virt/WDAT.wdat > create mode 100644 tests/data/acpi/x86/q35/WDAT.wdat > > -- > 2.47.3