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

[Pratyush Yadav]

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)

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.
>