From: Jan Kiszka <[email protected]> Sent: Monday, February 2, 2026 9:58 PM > > On 03.02.26 00:47, Long Li wrote: > >> From: Jan Kiszka <[email protected]> > >> > >> This resolves the follow splat and lock-up when running with PREEMPT_RT > >> enabled on Hyper-V: > > > > Hi Jan, > > > > It's interesting to know the use-case of running a RT kernel over Hyper-V. > > > > Can you give an example? > > > > - functional testing of an RT base image over Hyper-V > - re-use of a common RT base image, without exploiting RT properties > > > As far as I know, Hyper-V makes no RT guarantees of scheduling VPs for a VM. > > This is well understood and not our goal. We only need the kernel to run > correctly over Hyper-V with PREEMPT-RT enabled, and that is not the case > right now. > > Thanks, > Jan > > PS: Who had to idea to drop a virtual UART from Gen 2 VMs? Early boot > guest debugging is true fun now... >
Hmmm. I often do printk()-based debugging via a virtual UART in a Gen 2 VM. The Linux serial console outputs to that virtual UART and I see the printk() output in PuTTY on the Windows host. What specifically are you trying to do? I'm trying to remember if there's any unique setup required on a Gen 2 VM vs. a Gen 1 VM, and nothing immediately comes to mind. Though maybe it's just so baked into my process that I don't remember it! Michael
