On 05.02.26 06:42, Michael Kelley wrote: > 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! >
Indeed: Powershell> Set-VMComPort -VMName "Debian 13" 1 \\.\pipe\comport <Start VM> Powershell> putty -serial \\.\pipe\comport Well hidden... Jan -- Siemens AG, Foundational Technologies Linux Expert Center
