Hello, Avi Kivity wrote: > We get a page fault immediately (next instruction) after returning from > the guest when running with oprofile. The page fault address does not > match anything the instruction does, so presumably it is one of the > accesses the processor performs in order to service an NMI (ordinary > interrupts are masked; and the fact that it happens with oprofile > strengthens this assumption). Ah... okay, that's tricky but IIRC faults like that can be distinguished from regular ones via processor state, right? > If this is correct, the fault is not in the NMI handler itself, but in > one of the memory areas the cpu looks in to vector the NMI, which can be: > > - the IDT > - the GDT > - the TSS > - the NMI stack > > Except for the IDT these are per-cpu structure, though I don't know > whether they are allocated with the percpu infrastructure. Don't know where NMI stack is but all else are percpu. > Here is the code in question: > >> 3ae7: 75 05 jne 3aee<vmx_vcpu_run+0x26a> >> 3ae9: 0f 01 c2 vmlaunch >> 3aec: eb 03 jmp 3af1<vmx_vcpu_run+0x26d> >> 3aee: 0f 01 c3 vmresume >> 3af1: 48 87 0c 24 xchg %rcx,(%rsp) > > ^^^ fault, but not at (%rsp) Can you please post the full oops (including kernel debug messages during boot) or give me a pointer to the original message? Also, does the faulting address coincide with any symbol? Thanks. -- tejun -- 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
