On Wed, Mar 06, 2013 at 10:07:31AM +0100, Paolo Bonzini wrote: > Il 06/03/2013 09:56, Hu Tao ha scritto: > >> > > >> > Something like this should work (in SeaBIOS's src/acpi-dsdt-isa.dsl): > >> > > >> > Device(PEVT) { > >> > Name(_HID, EisaId("QEMU0001")) > >> > OperationRegion(PEOR, SystemIO, 0x505, 0x01) > >> > Field(PEOR, ByteAcc, NoLock, Preserve) { > >> > PEPT, 8, > >> > } > >> > > >> > Method(_STA, 0, NotSerialized) { > >> > Store(PEPT, Local0) > >> > If (LEqual(Local0, Zero)) { > >> > Return (0x00) > >> > } Else { > >> > Return (0x0F) > >> > } > >> > } > > IIUC, here _STA reads from ioport 0x505, if the result is 0, then the > > device is not present. Otherwise, the device is present. But as Gleb > > said, ''the data you read from unassigned port is not guarantied to be > > zero, it may depend on QEMU version''. What should I do to tell if the > > device is present or not correctly? > > The firmware is tied to the QEMU version, so you can rely on unassigned > ports returning zero. > > Later we can change this to use fw-cfg. > I thought we agreed to do it from the start :) -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html