Dongli Zhang <dongli.zhang@xxxxxxxxxx> writes: > Hi Vitaly, > > On 7/12/22 6:50 AM, Vitaly Kuznetsov wrote: >> Windows 10/11 guests with Hyper-V role (WSL2) enabled are observed to >> hang upon boot or shortly after when a non-default TSC frequency was >> set for L1. The issue is observed on a host where TSC scaling is > > Would you mind helping clarify if it is L1 or L2 that hangs? > > The commit message "Windows 10/11 guests with Hyper-V role (WSL2)" confuses me > if it is L1 or L2 (perhaps due to my lack of knowledge on hyper-v) that hangs. > I think it's L2 but I'm not sure: there's no easy way to interract with L1 (Hyper-V) directly, all the interfaces (UI, network,..) are handled by L2 (Windows). Prior to the observed 'hang' Hyper-V (L1) programms synthetic timer in KVM too far in the future but my guess is that it's doing that on Windows' (L2) behalf, basically just relaying the request. The issue only shows up with 'hv-reenlightenment' + 'hv-frequencies' (in QEMU's terms) features as in this case both Hyper-V (L1) and Windows (L2) trust the information about TSC frequency from KVM but the information turns out to be incorrect for Windows (L2). -- Vitaly
