Re: [Xen-devel] [PATCHv9 0/9] Xen: extend kexec hypercall for use with pv-ops kernels

[Daniel Kiper <daniel.kiper@xxxxxxxxxx>]

On Sat, Oct 19, 2013 at 12:14:24AM +0100, David Vrabel wrote:
> On 18/10/2013 19:40, Daniel Kiper wrote:
> > On Tue, Oct 08, 2013 at 05:55:01PM +0100, David Vrabel wrote:
> >> The series (for Xen 4.4) improves the kexec hypercall by making Xen
> >> responsible for loading and relocating the image.  This allows kexec
> >> to be usable by pv-ops kernels and should allow kexec to be usable
> >> from a HVM or PVH privileged domain.
> >
> > I could not load panic image because Xen crashes in following way:
> >
> > (XEN) ----[ Xen-4.4-unstable  x86_64  debug=y  Tainted:    C ]----
> [...]
> > (XEN) Xen call trace:
> > (XEN)    [<ffff82d080114ef2>] kimage_free+0x67/0xd2
> > (XEN)    [<ffff82d0801151f9>] do_kimage_alloc+0x29c/0x2f0
> > (XEN)    [<ffff82d0801152fe>] kimage_alloc+0xb1/0xe6
> > (XEN)    [<ffff82d0801144c0>] do_kexec_op_internal+0x68e/0x789
> > (XEN)    [<ffff82d0801145c9>] do_kexec_op+0xe/0x12
> > (XEN)    [<ffff82d0802268cb>] syscall_enter+0xeb/0x145
>
> The appended patch should fix this crash which only occurs if there's an
> error in do_kimage_alloc().

Patch had wrapped lines. I hope that I fixed it properly.
I cannot load panic kernel. kexec fails with following message:

kexec_load failed: Cannot assign requested address
entry       = 0x13f4f720 flags = 0x3e0001
nr_segments = 5
segment[0].buf   = 0x7f5057554e10
segment[0].bufsz = 0x2d4d20
segment[0].mem   = 0x13000000
segment[0].memsz = 0xc0f000
segment[1].buf   = 0x144e620
segment[1].bufsz = 0x3f28
segment[1].mem   = 0x13f4a000
segment[1].memsz = 0x4000
segment[2].buf   = 0x14464c0
segment[2].bufsz = 0x80e0
segment[2].mem   = 0x13f4f000
segment[2].memsz = 0xa000
segment[3].buf   = 0x1445aa0
segment[3].bufsz = 0x400
segment[3].mem   = 0x13f5a000
segment[3].memsz = 0x4000
segment[4].buf   = 0x7f5058ad4010
segment[4].bufsz = 0x9f400
segment[4].mem   = 0x13f5f000
segment[4].memsz = 0xa0000

Normal kexec crashes as previously.

I boot my system in following way:

multiboot /boot/xen.gz apic_verbosity=debug com1=115200,8n1 conring_size=256k \
  crashkernel=256m@64m dom0_mem=1g,max:1g guest_loglvl=all loglvl=all \
  sync_console console=com1,vga
module /boot/vmlinuz root=/dev/sda3 ro apic=debug fbcon=scrollback:256k \
  libata.ignore_hpa=1 raid=noautodetect earlyprintk=xen console=tty1 
console=hvc0

I load panic kernel with following command line:

/sbin/kexec -p /boot/vmlinuz --console-serial --serial=ttyS0 
--serial-baud=115200 \
  --append='root=/dev/sda3 ro apic=debug fbcon=scrollback:256k 
libata.ignore_hpa=1
            nr_cpus=1 raid=noautodetect earlyprintk=ttyS0,115200 console=tty1
            console=ttyS0,115200n8'

I load normal kernel with following command line:

/sbin/kexec -l /boot/vmlinuz --console-serial --serial=ttyS0 
--serial-baud=115200 \
  --append='root=/dev/sda3 ro apic=debug fbcon=scrollback:256k 
libata.ignore_hpa=1
            raid=noautodetect earlyprintk=ttyS0,115200 console=tty1
            console=ttyS0,115200n8'

I use xen-unstable tree with latest commit 
(f72cb6bbc10348f4f7671428e5db509731e9e6a5),
Linux Kernel 3.10.17 and kexec-tools with latest
commit (1cbddc80ddfe34cdcdac11c0562e4d8395c48b16)

If you need more info drop me a line.

Daniel

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