Red Hat Bugzilla – Bug 1039745
qemu vcpu hotplug support for q35 machine type
Last modified: 2015-03-05 04:43:15 EST
CPU hot-add was implemented for piix based machines and Q35 based machines still miss it. It's needed to factor out common ACPI bits of CPU hot-plug code and reuse it for Q35 as well. Patch to factor out need generic ACPI bits was posted as part of memory hotplug series http://lists.gnu.org/archive/html/qemu-devel/2013-11/msg02526.html Once it is committed, I can post CPU specific patch to add feature to Q35.
QE, Please retest when RHEL7.1 is ready.
upstream fix: http://lists.gnu.org/archive/html/qemu-devel/2014-01/msg00997.html
Update the component to qemu-kvm-rhev since this bz is fixed in qemu2.0, fix me if there is wrong. Best Regards, Junyi
Verify this bug with qemu-kvm-1.5.3-53.el7.x86_64 and qemu-kvm-1.5.3-66.el7.x86_64 and qemu-kvm-rhev-2.1.0-3.el7ev.preview.x86_64 For RHEL7.0 guest with qemu-kvm-rhev-2.1.0-3.el7ev.preview.x86_64 & qemu-kvm-1.5.3-66.el7.x86_64 & qemu-kvm-1.5.3-53.el7.x86_64 on Intel host. 1./usr/libexec/qemu-kvm -M q35 -smp 8,cores=2,threads=2,sockets=2,maxcpus=160... 2.{ "execute": "cpu-add", "arguments": { "id": 9 }} 3.check vcpu number from qemu-kvm HMP (qemu) info cpus * CPU #0: pc=0xfffff8037f21f1ff (halted) thread_id=13221 CPU #1: pc=0xfffff8037f21f1ff (halted) thread_id=13222 CPU #2: pc=0xfffff8037f21f1ff (halted) thread_id=13223 CPU #3: pc=0xfffff8037f21f1ff (halted) thread_id=13224 CPU #4: pc=0xfffff8000039f37e thread_id=13225 CPU #5: pc=0xfffff8037f21f1ff (halted) thread_id=13226 CPU #6: pc=0xfffff8037f21f1ff (halted) thread_id=13227 CPU #7: pc=0xfffff8037f21f1ff (halted) thread_id=13228 CPU #8: pc=0xfffff8037f21f1ff (halted) thread_id=13232 4. check vcpu number inside guest can find 9 vcpu inside guest from /proc/cpuinfo For win2012r2 guest with qemu-kvm-rhev-2.1.0-3.el7ev.preview.x86_64 on AMD host Got the same result with RHEL7.0 guest. Test summary. 1. qemu-kvm-1.5.3-53.el7.x86_64 & qemu-kvm-1.5.3-66.el7.x86_64 & qemu-kvm-rhev-2.1.0-3.el7ev.preview.x86_64 support vcpu hotplug 2. For linux and windows guest, both support vcpu hotplug on AMD & Intel host. Igor, 1.According to this test result above. Is this bug fixed? 2.qemu-kvm-1.5.3-53.el7.x86_64 and qemu-kvm-1.5.3-66.el7.x86_64 support vcpu hotplug as well. Is it expect?
(In reply to FuXiangChun from comment #6) > Verify this bug with qemu-kvm-1.5.3-53.el7.x86_64 and > qemu-kvm-1.5.3-66.el7.x86_64 and qemu-kvm-rhev-2.1.0-3.el7ev.preview.x86_64 > > For RHEL7.0 guest with qemu-kvm-rhev-2.1.0-3.el7ev.preview.x86_64 & > qemu-kvm-1.5.3-66.el7.x86_64 & qemu-kvm-1.5.3-53.el7.x86_64 on Intel host. > > 1./usr/libexec/qemu-kvm -M q35 -smp > 8,cores=2,threads=2,sockets=2,maxcpus=160... > > 2.{ "execute": "cpu-add", "arguments": { "id": 9 }} > > 3.check vcpu number from qemu-kvm HMP > (qemu) info cpus > * CPU #0: pc=0xfffff8037f21f1ff (halted) thread_id=13221 > CPU #1: pc=0xfffff8037f21f1ff (halted) thread_id=13222 > CPU #2: pc=0xfffff8037f21f1ff (halted) thread_id=13223 > CPU #3: pc=0xfffff8037f21f1ff (halted) thread_id=13224 > CPU #4: pc=0xfffff8000039f37e thread_id=13225 > CPU #5: pc=0xfffff8037f21f1ff (halted) thread_id=13226 > CPU #6: pc=0xfffff8037f21f1ff (halted) thread_id=13227 > CPU #7: pc=0xfffff8037f21f1ff (halted) thread_id=13228 > CPU #8: pc=0xfffff8037f21f1ff (halted) thread_id=13232 > > 4. check vcpu number inside guest > > can find 9 vcpu inside guest from /proc/cpuinfo > > > For win2012r2 guest with qemu-kvm-rhev-2.1.0-3.el7ev.preview.x86_64 on AMD > host > > Got the same result with RHEL7.0 guest. > > Test summary. > 1. qemu-kvm-1.5.3-53.el7.x86_64 & qemu-kvm-1.5.3-66.el7.x86_64 & > qemu-kvm-rhev-2.1.0-3.el7ev.preview.x86_64 support vcpu hotplug > > 2. For linux and windows guest, both support vcpu hotplug on AMD & Intel > host. > > Igor, > > 1.According to this test result above. > Is this bug fixed? looks like it is. > > 2.qemu-kvm-1.5.3-53.el7.x86_64 and qemu-kvm-1.5.3-66.el7.x86_64 support vcpu > hotplug as well. Is it expect? 1.5.3 supports CPU hotadd only for piix4 machine, if one tries to use it for q35 machine, CPU will be added (info cpus) but guest won't see it until reboot, since q35 ACPI parts are missing.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://rhn.redhat.com/errata/RHSA-2015-0624.html