On 01/30/14 07:37, Dietmar Maurer wrote: >> Does it work with TCG? > > It simply hangs a bit later if I use TCG, without any output on the console.
Strange. How recent qemu happens this with? The relevant emulation code (under "ljmp Ev" in "target-i386/translate.c") has been changed as recently as commit 78261634 (not in any release yet). > But It works perfectly when I switch back to the pxe-XX.rom files. > >> Also, can you try with a NIC model different from the default e1000? > > same behavior with e1000, rtl8139, pcnet These do match my results. Please allow me to summarize the rest of the thread: - New builds of iPXE contain funny jmp instructions. - They are only present in the qemu tree in the efi-*.rom files, the pxe-*.rom builds date back to much earlier. - When running the funny jmp instructions in a KVM guest, you either need "unrestricted_guest" support from the host CPU (check the "/sys/module/kvm_intel/parameters/unrestricted_guest" file when kvm-intel.ko is inserted), *or* you need to ask KVM to emulate invalid guest state, by passing "emulate_invalid_guest_state=1" to kvm-intel.ko -- check your module options under /etc/modprobe.d. (Note that you should rebuild the initramfs with dracut if you change those options.) - In the latter case (ie. unrestricted_guest==0 && emulate_invalid_guest_state==1), you will still run into an emulation problem on a current RHEL-6 host *later* (a different jmp insn in the iPXE builds). I filed RHBZ#1059496 for this and posted the backport last night. Gleb's upstream patches in question are e35b7b9c and ea79849d. Laszlo
