Similar to QEMU ARM/RISC-V, ENABLE_SMP_CLOCK_SYNC_TEST_ON_BOOT should not be on for x86 QEMU. But since it's x86 the kernel doesn't know it's running on QEMU when you build the kernel for a generic x86 CPU.

According to my colleague @dreamliner787-9 there's no reliable way of looking at CPUID to tell if you're being virtualised by QEMU.

I'm wondering if anyone has any other ideas for how we could skip the test at run-time if we detect we're running on QEMU, I'm still getting familiar with the x86 architecture myself.