other: 0.974 graphic: 0.974 device: 0.953 performance: 0.911 semantic: 0.898 permissions: 0.836 debug: 0.783 network: 0.776 KVM: 0.763 files: 0.744 socket: 0.700 vnc: 0.695 boot: 0.632 PID: 0.628 SB.PCI0.SMB0 device drivers unavailable 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. what is this shit? 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