Date: Tue, 6 Mar 2018 07:15:41 -0800 From: Peter Grehan <grehan@freebsd.org> To: Fabian Freyer <fabian.freyer@physik.tu-berlin.de> Cc: freebsd-virtualization@freebsd.org, rumpkernel-users@freelists.org Subject: Re: rumpkernel and bhyve: triple faults Message-ID: <651856d3-3c34-9930-cda1-62d41091f91f@freebsd.org> In-Reply-To: <C49D0E56-10A4-49D8-A843-E371395831B5@physik.tu-berlin.de> References: <C49D0E56-10A4-49D8-A843-E371395831B5@physik.tu-berlin.de>
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Hi Fabian, > 657 0 350887309700 vm testing[0]: handled exception vmexit at 0x102a56 > 656 0 350887309570 vm testing[0]: Exception 14 pending > 655 0 350887309442 vm testing[0]: Setting intr_shadow to 0 succeeded > 654 0 350887305126 vm testing[0]: Reflecting exception 14/0 into the guest > 653 0 350887302436 vm testing[0]: vm_exit_intinfo: info1(0x80000b0e) > 652 0 350887248280 vm testing[0]: Resume execution at 0x102a56 > 651 0 350887184160 vm testing[0]: vm_entry_intinfo: info1(0), info2(0x80000b0e), retinfo(0x80000b0e) > 650 0 350887184040 vm testing[0]: Exception 14 delivered: 0x80000b0e > 649 0 350887182668 vm testing[0]: handled exception vmexit at 0x102a56 Exception 14 is a page fault (SDM Vol3 ch 6.15). The exception type is "fault" which means it is delivered at the address it was detected at. This cascaded very quickly into a triple-fault, so it looks like it could possibly be an issue with the stack. One debug tool you do have is to get a register dump on exit, with 'bhyvectl --get-all --vm=<your vn name>'. For a page-fault, the virtual address that resulted in the fault will be in the CR2 register. From the code at the faulting address: > 0000000000102a50 <cons_init>: > 102a50: push rbx > 102a51: call 103540 <hypervisor_detect> > 102a56: cmp WORD PTR [rip-0x102a5c],0x0 # 2 <current_lwp+0x2> It's using RIP-relative addressing here, but objdump seems to think this may be an offset in the current_lwp structure - is it possible that may have an uninitialized value ? (I don't believe this has anything to do with VGA). later, Peter.
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