On 07/08/2015 01:02, Laszlo Ersek wrote: >> > The trace covers the full lifetime of the guest (I started tracing >> > before launching the guest, and I passed -no-reboot to qemu, so when the >> > guest crashed, QEMU exited.) >> > >> > This was on 3.10.0-299.el7.x86_64. > I repeated the test with EPT off. The guest doesn't crash this way, it spins in a busy loop. > > qemu-system-i38-32767 [002] 55142.911133: kvm_emulate_insn: 0:7ffd790b: 0f aa > qemu-system-i38-32767 [002] 55142.911139: kvm_cpuid: func 80000001 rax 6e8 rbx 0 rcx 0 rdx 100000 > qemu-system-i38-32767 [002] 55142.911148: kvm_enter_smm: vcpu 0: leaving SMM, smbase 0x7ffc0000 > qemu-system-i38-32767 [002] 55142.911150: kvm_mmu_get_page: existing sp gfn 7fe65 1/2 q3 --- !pge !nxe root 0 sync > qemu-system-i38-32767 [002] 55142.911151: kvm_mmu_get_page: existing sp gfn 7fe66 1/2 q3 --- !pge !nxe root 0 sync > qemu-system-i38-32767 [002] 55142.911151: kvm_mmu_get_page: existing sp gfn 7fe67 1/2 q3 --- !pge !nxe root 0 sync > qemu-system-i38-32767 [002] 55142.911151: kvm_mmu_get_page: existing sp gfn 7fe68 1/2 q3 --- !pge !nxe root 0 sync > qemu-system-i38-32767 [002] 55142.911152: kvm_entry: vcpu 0 > qemu-system-i38-32767 [002] 55142.911152: kvm_exit: reason EXCEPTION_NMI rip 0x7ffdb6b2 info 7fe88760 80000b0e > qemu-system-i38-32767 [002] 55142.911153: kvm_page_fault: address 7fe88760 error_code b > > And then the last triplet is repeated infinitely. > > 0x7ffdb6b2 is the address of the same first instruction executed after the RSM. > > The address 0x7fe88760 seems to fall into an EfiBootServicesData allocation, made in PEI (via a suitable HOB): > > Memory Allocation 0x00000004 0x7FE69000 - 0x7FE88FFF You probably should use "-cpu model,-lm,-nx". EFER is not part of the 32-bit state save map, so the EFER.NXE bit is not restored correctly on exit from SMM if you emulate a 32-bit CPU. I have not debugged yet why it works without KVM, nor why the symptoms are different between EPT and non-EPT. Paolo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
