Xen kernel fails to boot, d0v1 triple fault looks like the cuplrit

[Pratyush Yadav]

On Sat, May 19, 2018 at 3:45 PM, Pratyush Yadav <pratiy0100 at gmail.com> wrote:
> Hi,
>
> The line is
>
> /usr/src/sys/amd64/amd64/mp_machdep.c:307
>
> Also, I tried with dom0_max_vcpus=1 but it keeps rebooting (despite noreboot
> in the xen command line)

Correction: It boots with dom0_max_vcpus=1. It did not boot for me
earlier because I was trying to fix it by trying to make Xen from
source so I had actually deinstalled it when I tested with
max_vcpus=1. Now I reinstalled Xen and it works.

Thanks for the temporary workaround! Let me know if you want more info
about the panic.

>
> On Sat 19 May, 2018, 1:40 PM Roger Pau Monné, <roger.pau at citrix.com> wrote:
>>
>> On Fri, May 18, 2018 at 05:29:06PM +0530, Pratyush Yadav wrote:
>> > Hi,
>> >
>> > So I have been trying to get Xen to boot on my laptop. It is getting
>> > stuck with the following error messages:
>> >
>> > (XEN) Scrubbing free RAM on 1 nodes using 4 CPUs
>> > (XEN) [VT-D] DMAR: [DMA Read} Request device [0000:00:1a.0] fault addr
>> > 9ce13000. iommu reg - ffff82c000203000
>> > (XEN) [VT-D] DMAR: reason 06 - PTE read access is not set
>> > (XEN) ........... done
>> > (XEN) initial low memory virq threshold set at 0x200 pages.
>> > (XEN) Std. Loglevel: All
>> > (XEN) Guest Loglevel: All
>> > (XEN) Xen is keeping VGA console
>> > (XEN) Boot video device 00:02.0
>> > (XEN) ***Serial input -> DOM0 (type 'CTRL-a' three times to switch input
>> > to Xen)
>> > (XEN) Freed 320 kB init memory
>> > FreeBSD PVH running on xen-3.0-x86_64p
>> > Copyright (c) 1992-2018 The FreeBSD Project.
>> > Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993,
>> > 1994 The regents of the University of California. All rights reserved.
>> > FreeBSD is a registered trademark of The FreeBSD Foundation.
>> > FreeBSD 12.0-CURRENT #0 r333606: Mon May 14 19:59:08 UTC 2018
>> >
>> > root at releng3.nyi.freebsd.org:/usr/obj/usr/src/amd64.amd64/sys/GENERIC amd64
>> > WARNING: WITNESS option enabled, expect reduced performance.
>> > VT(vga): text 80x25
>> > CPU: Intel(R) Core(TM) i7-4710HQ CPU @ 2.50GHz (2494.22-MHz K8-class
>> > CPU)
>> >     Origin="GenuineIntel" Id=0x306c3 Family=0x6 Model=0x3c Stepping=3
>> >
>> > Features=0x17c1cbf5<FPU,DE,TSC,MSR,PAE,MCE.CX8.APIC,SEP,MCA,CMOV,PAT,ACPI,MMX
>> > FXSR,SSE,SSE2,HTT>
>> >
>> > Features2=0xf6f83203<SSE3,PCLMULQDQ,SSSE3,FMA,CX16,SSE4.1,SSE4.2,x2APIC,MOVBE
>> > POPCNT,AESNI,XSAVE,AVX,F16C,RDRAND,HV>
>> >     AMD Features=0x20101800<SYSCALL,<s12>NX,LM>
>> >     AMD Features2=0x21<<LAHF,ABM>
>> >     Structured Extended
>> > Features=0x2329<FSGSBASE,BMI1,AVX2,BMI2,ERMS,NFPUSG>
>> > Hypervisor: Origin = "XenVMMXenVMM"
>> > real memory  = 9991770112 (9528 MB)
>> > avail memory = 7936724992 (7569 MB)
>> > (XEN) d0v1 Triple fault - invoking HVM shutdown action 0
>> > (XEN) *** Dumping Dom0 vcpu#1 state: ***
>> > (XEN) ----[ Xen-4.7.2 x86_64 debug=n Not tainted ]----
>> > (XEN) CPU:    1
>> > (XEN) RIP:    0020:[<ffffffff8102042b>]
>> > (XEN) RFLAGS:  0000000000010016    CONTEXT: hvm guest (d0v1)
>> > (XEN) rax: 0000000000000000   rbx: ffffffff8201c100   rcx:
>> > 0000000000000001
>> > (XEN) rdx: 0000000000003078   rsi: ffffffff81b992f8   rdi:
>> > fffffe0003bb6078
>> > (XEN) rbp: fffffe00009ffff0   rsp: fffffe00009fffa0   r8:
>> > 00000000ffffffff
>> > (XEN) r15: 0000000000000400   cr0: 0000000000000011   cr4:
>> > 0000000000000020
>> > (XEN) cr3: 00000000035a4000   cr2: 0000000000000ff0
>> > (XEN) ds: 0028   es: 0028   fs: 0028   gs: 0028   ss: 0028   cs: 0020
>> > (XEN) Guest stack trace from rsp=fffffe00009fffa0:
>> > (XEN)   Fault while accessing guest memory.
>> > (XEN) Hardware Dom0 halted: halting machine
>> >
>> > Any idea why this is happening and how can I fix this?
>>
>> Can you execute:
>>
>> addr2line -e /usr/lib/debug/boot/kernel/kernel.debug ffffffff8102042b
>>
>> This should print a file and line number that would help in order to
>> debug what's going on.
>>
>> Since it seems like the crash is caused by a triple fault on an AP,
>> you can try to boot with dom0_max_vcpus=1 on the xen_cmdline, that
>> might prevent the panic from happening.
>>
>> We need however to figure out what's going on and fix it.
>>
>> Thanks, Roger.



-- 
Regards,
Pratyush Yadav