graphic: 0.974 user-level: 0.973 device: 0.953 mistranslation: 0.947 virtual: 0.943 peripherals: 0.937 assembly: 0.932 architecture: 0.913 performance: 0.911 semantic: 0.898 ppc: 0.846 permissions: 0.836 register: 0.834 kernel: 0.804 arm: 0.799 debug: 0.783 network: 0.776 risc-v: 0.767 KVM: 0.763 hypervisor: 0.744 files: 0.744 VMM: 0.742 socket: 0.700 vnc: 0.695 i386: 0.681 TCG: 0.661 boot: 0.632 PID: 0.628 x86: 0.622 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