When running windows 2016 server guests we have encountered a problem with ACPI representation of CPU devices. This windows version contains a hidinterrupt.sys driver which looks for ACPI device node with _HID set to "ACPI0010" and "ACPI0011". ACPI0010 is also a valid id for CPU container device which qemu uses.
hidinterrupt driver takes over (even though it fails) ACPI0010 node and thus hides its children -- the CPUs -- from the regular ACPI enumeration. So there are no processors in the Windows device tree Device Manager or "!devnode 0 1" in the debugger. hidinterrupt.inf as shipped with Windows 2016 has both ACPI0011 and ACPI0010; the record for the latter is preceded with a comment "This Id is not to be used. It will be removed once everyone has stopped using it." So I guess the typo was not in the driver but in the ACPI tables of some device(s) which the driver wanted to support despite the bug. For reference this is a known issue: https://bugzilla.redhat.com/show_bug.cgi?id=1377155#c31 This change works around this problem by setting qemu CPU container ACPI _HID to compatible PNP0A05. Signed-off-by: Evgeny Yakovlev <eyakov...@virtuozzo.com> --- hw/acpi/cpu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/hw/acpi/cpu.c b/hw/acpi/cpu.c index a233fe1..b93db40 100644 --- a/hw/acpi/cpu.c +++ b/hw/acpi/cpu.c @@ -397,7 +397,7 @@ void build_cpus_aml(Aml *table, MachineState *machine, CPUHotplugFeatures opts, Aml *rm_evt = aml_name("%s.%s", cphp_res_path, CPU_REMOVE_EVENT); Aml *ej_evt = aml_name("%s.%s", cphp_res_path, CPU_EJECT_EVENT); - aml_append(cpus_dev, aml_name_decl("_HID", aml_string("ACPI0010"))); + aml_append(cpus_dev, aml_name_decl("_HID", aml_string("PNP0A05"))); aml_append(cpus_dev, aml_name_decl("_CID", aml_eisaid("PNP0A05"))); method = aml_method(CPU_NOTIFY_METHOD, 2, AML_NOTSERIALIZED); -- 1.8.3.1
