x-hv-synic-kvm-only does two things: 1) Disables in-QEMU synic and this should be unrelated to the issue as it is unrelated to stimers.
2) Doesn't clear guest pages (HV_X64_MSR_SIEFP/HV_X64_MSR_SIMP). This can actually be related to huge pages if the cleanup is causing huge page split. Synic pages are 4k. I still fail to see how this is vhost related. I'll try to take a look. -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1811533 Title: Unstable Win10 guest with qemu 3.1 + huge pages + hv_stimer Status in QEMU: Confirmed Bug description: Host: Gentoo linux x86_64, kernel 4.20.1 Qemu 3.1.0 CPU: Intel i7 6850K Chipset: X99 Guest: Windows 10 Pro 64bit (1809) Machine type: pc-q35_3.1 Hyper-V enlightenments: hv_stimer,hv_reenlightenment,hv_frequencies,hv_vapic,hv_reset,hv_synic,hv_runtime,hv_vpindex,hv_time,hv_relaxed,hv_spinlocks=0x1fff Memory: 16GB backed by 2MB huge pages Issue: Once guest is started, log gets flooded with: qemu-system-x86_64: vhost_region_add_section: Overlapping but not coherent sections at 103000 or qemu-system-x86_64: vhost_region_add_section:Section rounded to 0 prior to previous 1f000 (line endings change) and as time goes guest loses network access (virtio-net-pci) and general performance diminishes to extent of freezing applications. Observations: 1) problem disappears when hv_stimer is removed 2) problem disappears when memory backing with huge pages is disabled 3) problem disappears when machine type is downgraded to pc-q35_3.0 To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1811533/+subscriptions
