Hello I wrote some module in my hobby OS kernel to issue the performance monitoring interrupt (PMI) on instructions counter overflow. It works well on my machine (Intel core i5). But when I run it on qemu using
qemu-system-x86_64 -enable-kvm -cpu host -m 256 -serial mon:stdio -cdrom var/run/hypervisor.iso the interrupt does never fire. However, Instruction counting works well in qemu. Is there anything I am missing? Does it require any special configuration to get the PMI fired on qemu? This is how I configure msr registers to activate PMI Msr::write(Msr::MSR_PERF_GLOBAL_CTRL, 0x700000003); Msr::write(Msr::MSR_PERF_FIXED_CTRL, 0xa); Msr::write(Msr::IA32_PERFEVTSEL0, 0x004100c5); Program the PMI for 0x1000 instructions Msr::write(Msr::IA32_PERF_GLOBAL_OVF_CTRL, 1ull << 32); Msr::write(Msr::MSR_PERF_FIXED_CTR0, 0xFFFFEFFF | 0xFFFF00000000); Thanks -- Parfait T.
