On Tue, Mar 16, 2021, Jan Kiszka wrote: > On 16.03.21 17:50, Sean Christopherson wrote: > > Rather than block all events in KVM, what about having QEMU "pause" the timer? > > E.g. save MSR_TSC_DEADLINE and APIC_TMICT (or inspect the guest to find out > > which flavor it's using), clear them to zero, then restore both when > > single-stepping is disabled. I think that will work? > > > > No one can stop the clock, and timers are only one source of interrupts. > Plus they do not all come from QEMU, some also from KVM or in-kernel > sources directly. But are any other sources of interrupts a chronic problem? I 100% agree that this would not be a robust solution, but neither is blocking events in KVM. At least with this approach, the blast radius is somewhat contained. > Would quickly become a mess. Maybe, but it'd be Qemu's mess ;-)