Messages in this thread | | | From | Paolo Bonzini <> | Subject | [PATCH 0/2] KVM: x86: do not mix raw and monotonic clocks in kvmclock | Date | Wed, 22 Jan 2020 15:22:31 +0100 |
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Commit 53fafdbb8b21f ("KVM: x86: switch KVMCLOCK base to monotonic raw clock") changed kvmclock to use tkr_raw instead of tkr_mono. However, the default kvmclock_offset for the VM was still based on the monotonic clock and, if the raw clock drifted enough from the monotonic clock, this could cause a negative system_time to be written to the guest's struct pvclock. RHEL5 does not like it and (if it boots fast enough to observe a negative time value) it hangs.
This series fixes the issue by using the raw clock everywhere.
(And this, ladies and gentlemen, is why I was not applying patches to the KVM tree. I saw this before Christmas and could only reproduce it today, since it requires almost 2 weeks of uptime to reproduce on my machine. Of course, once you have the reproducer the fix is relatively easy to come up with).
Paolo
Paolo Bonzini (2): KVM: x86: reorganize pvclock_gtod_data members KVM: x86: use raw clock values consistently
arch/x86/kvm/x86.c | 67 ++++++++++++++++++++++++++++-------------------------- 1 file changed, 35 insertions(+), 32 deletions(-)
-- 1.8.3.1
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