On Tue, Aug 29, 2023, Marc Haber wrote: > On Tue, Aug 29, 2023 at 07:53:45AM -0700, Sean Christopherson wrote: > > What is different between the bad host(s) and the good host(s)? E.g. kernel, QEMU, > > The bad host is an APU ("AMD GX-412TC SOC") with 4 GB of RAM, one of the > good hosts is a "Xeon(R) CPU E3-1246 v3" with 32 GB of RAM. I don't expect it to help, but can you try booting the bad host with "spec_rstack_overflow=off"? > system configuration is from the same ansible playbook, but of course there > are differences. Can you capture the QEMU command lines for the good and bad hosts? KVM doesn't get directly involved in serial port emulation; if the blamed commit in 6.5 is triggering unexpected behavior then QEMU is a better starting point than KVM.