Hello, commit c3bc26d4b4e3 (ACPICA: ACPI 2.0, Hardware: Add access_width/bit_offset support in acpi_hw_read()) broke booting of my KVM test guest. When I revert that commit and commit 66b1ed5aa8d (ACPICA: ACPI 2.0, Hardware: Add access_width/bit_offset support for acpi_hw_write()) which looks similar, the vm boots again. The problem manifests itself that the qemu-kvm just aborts after the kernel prints: [ 0.333707] ACPI: bus type PCI registered [ 0.335494] PCI: Using configuration type 1 for base access [ 0.472716] ACPI: Added _OSI(Module Device) [ 0.475360] ACPI: Added _OSI(Processor Device) [ 0.476012] ACPI: Added _OSI(3.0 _SCP Extensions) [ 0.480035] ACPI: Added _OSI(Processor Aggregator Device) [ 0.494742] ACPI: 2 ACPI AML tables successfully acquired and loaded [ 0.496003] For working kernel the messages continue like: [ 0.507616] ACPI: Interpreter enabled [ 0.508018] ACPI: (supports S0 S5) [ 0.509129] ACPI: Using IOAPIC for interrupt routing [ 0.510717] PCI: Using host bridge windows from ACPI; if necessary, use "pci=nocrs" and report a bug [ 0.533308] ACPI: PCI Root Bridge [PCI0] (domain 0000 [bus 00-ff]) [ 0.535049] acpi PNP0A03:00: _OSC: OS supports [Segments] [ 0.536111] acpi PNP0A03:00: _OSC failed (AE_NOT_FOUND); disabling ASPM [ 0.538702] PCI host bridge to bus 0000:00 Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html