Bug 1992479
Summary: | Detecting TSC timer frequencies requires too many privileges | |||
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Product: | Red Hat Enterprise Linux Advanced Virtualization | Reporter: | Roman Mohr <rmohr> | |
Component: | libvirt | Assignee: | Michal Privoznik <mprivozn> | |
Status: | CLOSED ERRATA | QA Contact: | Luyao Huang <lhuang> | |
Severity: | high | Docs Contact: | ||
Priority: | unspecified | |||
Version: | 8.4 | CC: | chhu, jdenemar, jsuchane, lmen, mprivozn, pkrempa, virt-maint, xuzhang, ymankad | |
Target Milestone: | rc | Keywords: | Upstream, ZStream | |
Target Release: | 8.5 | |||
Hardware: | Unspecified | |||
OS: | Unspecified | |||
Whiteboard: | ||||
Fixed In Version: | libvirt-7.6.0-3.module+el8.5.0+12510+80564ecf | Doc Type: | If docs needed, set a value | |
Doc Text: | Story Points: | --- | ||
Clone Of: | ||||
: | 1996130 (view as bug list) | Environment: | ||
Last Closed: | 2021-11-16 07:55:01 UTC | Type: | Bug | |
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: | 1996130 |
Description
Roman Mohr
2021-08-11 07:54:25 UTC
Michal it would be great if we could get a backport. The commit from upstream issue #188 is: commit 5df2c49263338da7221f24b3ad67ffd21d88047c Author: Daniel P. Berrangé <berrange> Date: Wed Aug 4 18:05:59 2021 +0100 util: directly query KVM for TSC scaling support We currently query the host MSRs to determine if TSC scaling is supported. This works OK when running privileged and can open the /dev/cpu/0/msr. When unprivileged we fallback to querying MSRs from /dev/kvm. This is incorrect because /dev/kvm only reports accurate info for MSRs that are valid to use from inside a guest. The TSC scaling support MSR is not, thus we always end up reporting lack of TSC scaling when unprivileged. The solution to this is easy, because KVM can directly report whether TSC scaling is available, which matches what QEMU will do at startup. Closes: https://gitlab.com/libvirt/libvirt/-/issues/188 Reported-by: Roman Mohr <rmohr> Reviewed-by: Michal Privoznik <mprivozn> Signed-off-by: Daniel P. Berrangé <berrange> v7.6.0-53-g5df2c49263 Preverify this bug with rebuild libvirt with patch: https://mailman-int.corp.redhat.com/archives/rhvirt-patches/2021-August/msg00103.html Verify this bug with libvirt-daemon-7.6.0-3.module+el8.5.0+12510+80564ecf.x86_64 with the same steps in bug 1996130 comment 4. 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 (virt:av bug fix and enhancement update), 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://access.redhat.com/errata/RHBA-2021:4684 |