I noticed this as well. Apparently it was introduced in the following commit:
https://github.com/qemu/qemu/commit/ebe15582cafeb944a1c6e99aa526e81a1551c567 Saying: --- pc: Add an SMB0 ACPI device to q35 This is so I2C devices can be found in the ACPI namespace. Currently that's only IPMI, but devices can be easily added now. Adding the devices required some PCI information, and the bus itself to be added to the PCMachineState structure. Note that this only works on Q35, the ACPI for PIIX4 is not capable of handling an SMBus device. Cc: Michael S. Tsirkin <m...@redhat.com> Cc: Igor Mammedov <imamm...@redhat.com> Signed-off-by: Corey Minyard <cminy...@mvista.com> Reviewed-by: Paolo Bonzini <pbonz...@redhat.com> --- -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1856724 Title: SB.PCI0.SMB0 device drivers unavailable Status in QEMU: New Bug description: QEMU 4.2 introduces new device with this code: static void build_smb0(Aml *table, I2CBus *smbus, int devnr, int func) { Aml *scope = aml_scope("_SB.PCI0"); Aml *dev = aml_device("SMB0"); aml_append(dev, aml_name_decl("_HID", aml_eisaid("APP0005"))); aml_append(dev, aml_name_decl("_ADR", aml_int(devnr << 16 | func))); build_acpi_ipmi_devices(dev, BUS(smbus), "\\_SB.PCI0.SMB0"); aml_append(scope, dev); aml_append(table, scope); } It is detected by Windows 10 as 'Unknown Device' and there is no driver available. Please provide a working Windows driver or give ability to disable this device. To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1856724/+subscriptions