https://bugzilla.kernel.org/show_bug.cgi?id=217799 --- Comment #3 from Roman Mamedov (rm+bko@xxxxxxxxxxx) --- Hello, Unfortunately I am not in a position to easily do bisects. But as noted above, setting "spec_rstack_overflow=off" is enough to solve it. Further info, trying with an XP x64 install ISO provided by Microsoft: https://archive.org/details/windows-xp-professional-x64-edition With "spec_rstack_overflow=off", it works fine. But in the default state of this new mitigation (which is "safe RET, no microcode" on my machine), the install ISO hangs at the "Setup is starting Windows" message. So if anyone wants to reproduce on their local machine, there is now a quick and legal way to do so. My QEMU command-line: kvm -cpu host -m 2048 -machine pc,mem-merge=on,accel=kvm -vnc [::]:24 -device ide-hd,drive=drive0,bus=ide.0 -drive if=none,id=drive0,cache=writeback,aio=threads,format=raw,discard=unmap,detect-zeroes=off,file=xp.img -rtc base=localtime -cdrom xp64ce.iso -boot d I should add that when a VM is in this stuck state, the CPU load by QEMU process is 0% (not 100%). And I am not sure why the default mitigation state says "no microcode", as I use a 2023-08-08 updated microcode package from Debian. # dmesg | grep microcode [ 0.401618] Speculative Return Stack Overflow: IBPB-extending microcode not applied! [ 0.401618] Speculative Return Stack Overflow: Mitigation: safe RET, no microcode [ 1.051941] microcode: CPU0: patch_level=0x0a201016 [ 1.051947] microcode: CPU1: patch_level=0x0a201016 [ 1.051953] microcode: CPU2: patch_level=0x0a201016 [ 1.051960] microcode: CPU3: patch_level=0x0a201016 [ 1.051967] microcode: CPU4: patch_level=0x0a201016 [ 1.051973] microcode: CPU5: patch_level=0x0a201016 [ 1.051981] microcode: CPU6: patch_level=0x0a201016 [ 1.051989] microcode: CPU7: patch_level=0x0a201016 [ 1.051996] microcode: CPU8: patch_level=0x0a201016 [ 1.052003] microcode: CPU9: patch_level=0x0a201016 [ 1.052010] microcode: CPU10: patch_level=0x0a201016 [ 1.052018] microcode: CPU11: patch_level=0x0a201016 [ 1.052024] microcode: CPU12: patch_level=0x0a201016 [ 1.052030] microcode: CPU13: patch_level=0x0a201016 [ 1.052036] microcode: CPU14: patch_level=0x0a201016 [ 1.052041] microcode: CPU15: patch_level=0x0a201016 [ 1.052046] microcode: CPU16: patch_level=0x0a201016 [ 1.052052] microcode: CPU17: patch_level=0x0a201016 [ 1.052058] microcode: CPU18: patch_level=0x0a201016 [ 1.052064] microcode: CPU19: patch_level=0x0a201016 [ 1.052070] microcode: CPU20: patch_level=0x0a201016 [ 1.052076] microcode: CPU21: patch_level=0x0a201016 [ 1.052082] microcode: CPU22: patch_level=0x0a201016 [ 1.052088] microcode: CPU23: patch_level=0x0a201016 [ 1.052092] microcode: Microcode Update Driver: v2.2. -- You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.
