vmm: call notify_guest_clock_paused for Hyper-V guests - #7933
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rbradford merged 1 commit intoMar 31, 2026
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We reviewed this internally and also think this is a good fix. Thanks!
Previously, KVM_KVMCLOCK_CTRL was skipped when kvm_hyperv=on because Windows does not use pvclock directly. However, KVM internally uses pvclock data structures as the basis for computing the Hyper-V Reference TSC page parameters. Not calling KVM_KVMCLOCK_CTRL means there is no mechanism to signal time discontinuity to Windows guests after pause/resume, contributing to multi-minute hangs. Remove the kvm_hyperv guard so all guests receive the clock-paused notification. Signed-off-by: CMGS <[email protected]>
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rbradford
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Backport [0]. Previously, KVM_KVMCLOCK_CTRL was skipped when kvm_hyperv=on because Windows does not use pvclock directly. However, KVM internally uses pvclock data structures as the basis for computing the Hyper-V Reference TSC page parameters. Not calling KVM_KVMCLOCK_CTRL means there is no mechanism to signal time discontinuity to Windows guests after pause/resume, contributing to multi-minute hangs. Remove the kvm_hyperv guard so all guests receive the clock-paused notification. [0] cloud-hypervisor#7933 Signed-off-by: CMGS <[email protected]>
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Backport [0]. Previously, KVM_KVMCLOCK_CTRL was skipped when kvm_hyperv=on because Windows does not use pvclock directly. However, KVM internally uses pvclock data structures as the basis for computing the Hyper-V Reference TSC page parameters. Not calling KVM_KVMCLOCK_CTRL means there is no mechanism to signal time discontinuity to Windows guests after pause/resume, contributing to multi-minute hangs. Remove the kvm_hyperv guard so all guests receive the clock-paused notification. [0] cloud-hypervisor#7933 Signed-off-by: CMGS <[email protected]>
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Previously, KVM_KVMCLOCK_CTRL was skipped when kvm_hyperv=on because Windows does not use pvclock directly. However, KVM internally uses pvclock data structures as the basis for computing the Hyper-V Reference TSC page parameters. Not calling KVM_KVMCLOCK_CTRL means there is no mechanism to signal time discontinuity to Windows guests after pause/resume, contributing to multi-minute hangs.
Remove the kvm_hyperv guard so all guests receive the clock-paused notification.
close #7931