This series provides support for booting mach-virt machines with non-flat cpu topology, i.e. enabling the extended options of the '-smp' command line parameter (sockets,cores,threads). Both DT and ACPI description generators are added. We only apply the new feature to 3.1 and later machine types, as the change is guest visible, even when no command line change is made. This is because the basic '-smp <N>' parameter makes the assumption that <N> refers to the number of sockets, but when no topology description is provided, Linux will use the MPIDR to guess. Neither the MPIDR exposed to the guest when running with KVM nor TCG currently provides socket information, leaving Linux to assume all processing elements are cores in the same socket. For example, before this series '-smp 4' would show up in the guest as
CPU(s): 4 On-line CPU(s) list: 0-3 Thread(s) per core: 1 Core(s) per socket: 4 Socket(s): 1 and after it shows up as CPU(s): 4 On-line CPU(s) list: 0-3 Thread(s) per core: 1 Core(s) per socket: 1 Socket(s): 4 It's not expected that this should be a problem, but it's worth considering. The only way to avoid the silent change is for QEMU to provide boards a way to override the default '-smp' parsing function. Otherwise, if a user wants to avoid a guest visible change, but still use a 3.1 or later mach-virt machine type, then they must ensure the command line specifies a single socket, e.g. '-smp sockets=1,cores=4' Thanks, drew Andrew Jones (6): hw/arm/virt: Add virt-3.1 machine type device_tree: add qemu_fdt_add_path hw/arm/virt: DT: add cpu-map hw/arm/virt-acpi-build: distinguish possible and present cpus virt-acpi-build: add PPTT table hw/arm/virt: cpu topology: don't allow threads device_tree.c | 24 +++++++++++++ hw/acpi/aml-build.c | 50 ++++++++++++++++++++++++++ hw/arm/virt-acpi-build.c | 25 ++++++++++--- hw/arm/virt.c | 69 +++++++++++++++++++++++++++++++++--- include/hw/acpi/aml-build.h | 2 ++ include/hw/arm/virt.h | 1 + include/sysemu/device_tree.h | 1 + 7 files changed, 162 insertions(+), 10 deletions(-) -- 2.17.1
