Hello, I have encountered a problem trying to hotplug a CPU in my x86_64 guest setup. host os: x86_64 debian-squeeze (2.6.32-5-amd64 kernel) qemu-kvm: 0.14.1 or latest, both with the following (not-accepted) patch to allow hotplug on the main_system_bus applied: http://lists.gnu.org/archive/html/qemu-devel/2010-08/msg00850.html guest os: x86_64 debian-testing with 2.6.39-2-amd64 kernel or debian stable-squeeze with 2.6.32-5-amd64. example qemu-kvm command line (others have also been tried, this is the simplest): /opt/qemu-kvm/bin/qemu-system-x86_64 -enable-kvm -M pc -smp 1,maxcpus=2 -drive file=/opt/images/wheezy.qcow2 -monitor stdio My first issue is regarding the acpi event delivery: I am running "udevadm monitor" in my guest OS. When I issue the cpu-hotplug on my qemu-monitor: qemu_monitor: cpu_set 1 online No udev-acpi event appears in the udevadm monitor of the guest. if i issue a pci-device hotplug command afterwards e.g. adding a NIC: qemu_monitor: pci_add auto nic then the cpu-hotplug acpi/udev events appear in the udev monitor: KERNEL[1311086666.114132] add /devices/LNXSYSTM:00/device:00/LNXCPU:01 (acpi) KERNEL[1311086666.119475] add /devices/system/cpu/cpu1 (cpu) KERNEL[1311086666.120699] add /devices/virtual/thermal/cooling_device1 (thermal) UDEV [1311086666.158445] add /devices/system/cpu/cpu1 (cpu) UDEV [1311086666.159925] add /devices/virtual/thermal/cooling_device1 (thermal) UDEV [1311086666.174848] add /devices/LNXSYSTM:00/device:00/LNXCPU:01 (acpi) So only then is the./sys/devices/system/cpu/cpu1/ directory created. Is the acpi event supposed to be delivered to the guest OS immediately after the cpu_set command? Or is what I described expected behaviour? I am probably missing something, as issuing a pci_add device command seems irrelevant for the purpose of a CPU-hotplug acpi event. My second issue: after the successful creation of the cpu1 directory I try to online the cpu: echo 1 > /sys/devices/system/cpu/cpu1/online bash: echo: write error: Input/output error in the guest, dmesg reports: [ 2325.376355] Booting Node 0 Processor 1 APIC 0x1 [ 2325.376357] smpboot cpu 1: start_ip = 9a000 [ 2330.821306] CPU1: Not responding. and subsequent writes to /sys/devices/system/cpu/cpu1/online return invalid argument. Is there an obvious problem with the setup I have described? The same problem was observed with other -smp,maxcpus options as well e.g. -smp 2,macpus=4 and trying to online cpu3. I have also tried to specify "-cpu phenom" in the qemu command line, with no effect. qemu-0.14.1 has seabios-0.6.1 or 0.6.2 I believe, both of which include cpu hotplug support. I have also tried the newest seabios (from repository) to be on the safe side with the same result, so this doesn't seem to be a bios problem. thanks for any help, - Vasilis -- 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
