Bug 514912
| Summary: | [LTC 5.5 FEAT] CPU_DYING notifiers [201996] | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 5 | Reporter: | IBM Bug Proxy <bugproxy> |
| Component: | kvm | Assignee: | Eduardo Habkost <ehabkost> |
| Status: | CLOSED DUPLICATE | QA Contact: | Lawrence Lim <llim> |
| Severity: | high | Docs Contact: | |
| Priority: | high | ||
| Version: | 5.5 | CC: | hpicht, jjarvis, tools-bugs, virt-maint, ykaul |
| Target Milestone: | beta | ||
| Target Release: | 5.5 | ||
| Hardware: | All | ||
| OS: | All | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2009-08-26 20:47:43 UTC | Type: | --- |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
| Bug Depends On: | |||
| Bug Blocks: | 481160 | ||
*** This bug has been marked as a duplicate of bug 510814 *** |
=Comment: #0================================================= Emily J. Ratliff <ratliff.com> - 1. Feature Overview: Feature Id: [201996] a. Name of Feature: CPU_DYING notifiers b. Feature Description When kvm-intel.ko is loaded, regardless of whether any virtual machines are running, offlining/onlining of physical CPUs on the host results in failure. This can lead to confusion from a user because it is not obvious that CPU hotplug failed due to the kvm module being loaded. Hotplug fails because 2.6.18 lacked sufficient infrastructure to notify KVM so that it could disable/enable virtualization support on the removed/added physical CPUs. This infrastructure has subsequently been added to Linux by: commit db912f963909b3cbc3a059b7528f6a1a1eb6ffae Author: Avi Kivity <avi> Date: Thu May 24 12:23:10 2007 +0300 HOTPLUG: Add CPU_DYING notifier KVM wants a notification when a cpu is about to die, so it can disable hardware extensions, but at a time when user processes cannot be scheduled on the cpu, so it doesn't try to use virtualization extensions after they have been disabled. This adds a CPU_DYING notification. The notification is called in atomic context on the doomed cpu. Signed-off-by: Avi Kivity <avi> See http://lkml.org/lkml/2007/5/24/108 for the full series. See Bug 54637 <https://bugzilla.linux.ibm.com/show_bug.cgi?id=54637> - RIT320894- CPU onlining fails with I/O error when kvm_intel is loaded 2. Feature Details: Sponsor: LTC Architectures: x86_64 Arch Specificity: Purely Common Code Affects Core Kernel: Yes Delivery Mechanism: Backport Category: xSeries Request Type: Kernel - Enhancement from Upstream d. Upstream Acceptance: Accepted Sponsor Priority 1 f. Severity: High IBM Confidential: no Code Contribution: 3rd party code g. Component Version Target: 3. Business Case Make Virtualization more robust.. 4. Primary contact at Red Hat: John Jarvis jjarvis 5. Primary contacts at Partner: Project Management Contact: Stephanie Glass, sglass.com Technical contact(s): Frank Novak, fnovak.com Anthony Liguori, aliguori.com IBM Manager: Warren Grunbok II, grunbok.com