Re: [Xen-devel] [questions] Dom0/DomU on ARM under Xen

[Alexey Klimov <trashsee@xxxxxxxxx>]

2012/8/1 Alexey Klimov <trashsee@xxxxxxxxx>:
> And i saw that Ian set up git repository for xen with latest patches
> for ARM. So i'll try to use this repository.

Hello Stefano and Ian,

I used new Ian xen-unstable git repository
(git://xenbits.xen.org/people/ianc/xen-unstable.git arm-for-4.) and
Stefano linux kernel git repository (
git://xenbits.xen.org/people/sstabellini/linux-pvhvm.git
3.5-rc7-arm-2) with additional patches:

- for linux kernel "xen/events: fix unmask_evtchn for PV on HVM guests",
- ARM hypercall ABI: 64 bit ready patch series for xen and attached
few versions of xcbuild (early version of Ian and latest version).
After applying 64-bit ready patches i observed such errors when
building xen and tools:

1)
for i in public/callback.h public/dom0_ops.h public/elfnote.h
public/event_channel.h public/features.h public/grant_table.h
public/kexec.h public/mem_event.h public/memory.h public/nmi.h
public/physdev.h public/platform.h public/sched.h public/tmem.h
public/trace.h public/vcpu.h public/version.h public/xen-compat.h
public/xen.h public/xencomm.h public/xenoprof.h public/hvm/e820.h
public/hvm/hvm_info_table.h public/hvm/hvm_op.h public/hvm/ioreq.h
public/hvm/params.h public/io/blkif.h public/io/console.h
public/io/fbif.h public/io/fsif.h public/io/kbdif.h
public/io/libxenvchan.h public/io/netif.h public/io/pciif.h
public/io/protocols.h public/io/ring.h public/io/tpmif.h
public/io/usbif.h public/io/vscsiif.h public/io/xenbus.h
public/io/xs_wire.h; do gcc -ansi -include stdint.h -Wall -W -Werror
-S -o /dev/null -xc $i || exit 1; echo $i; done >headers.chk.new
public/version.h:61:5: error: unknown type name 'xen_ulong_t'
make[3]: *** [headers.chk] Error 1
make[3]: Leaving directory `/src/xen/xen/include'

Fixed by inserting #include "arch-arm.h" in xen/include/public/version.h

2)
building 'xc' extension
gcc -fno-strict-aliasing -DNDEBUG -g -fwrapv -O2 -Wall
-Wstrict-prototypes -O1 -fno-omit-frame-pointer -marm -g
-fno-strict-aliasing -std=gnu99 -Wall -Wstrict-prototypes
-Wdeclaration-after-statement -Wno-unused-but-set-variable
-D__XEN_TOOLS__ -MMD -MF .build.d -D_LARGEFILE_SOURCE
-D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE
-fno-optimize-sibling-calls -fPIC -I../../tools/include
-I../../tools/libxc -Ixen/lowlevel/xc -I/usr/include/python2.7 -c
xen/lowlevel/xc/xc.c -o
build/temp.linux-armv7l-2.7/xen/lowlevel/xc/xc.o -fno-strict-aliasing
-Werror
xen/lowlevel/xc/xc.c: In function 'pyxc_xeninfo':
xen/lowlevel/xc/xc.c:1442:5: error: format '%lx' expects argument of
type 'long unsigned int', but argument 4 has type 'xen_ulong_t'
[-Werror=format]
xen/lowlevel/xc/xc.c:1442:5: error: format '%lx' expects argument of
type 'long unsigned int', but argument 4 has type 'xen_ulong_t'
[-Werror=format]
cc1: all warnings being treated as errors

Just commented snprintf(str, sizeof(str), "virt_start=0x%lx",
p_parms.virt_start); in xc.c

Then it compiled and i tried to run DomU. It looks like allocation
console_pfn and xenstore_pfn in alloc_magic_pages() in xc_dom_arm.c
creates real pain for me. With this allocation/patch xen prints "bad
p2m lookup" messages before booting DomU
(XEN) bad p2m lookup
(XEN) dom1 IPA 0x0000000090000000
(XEN) P2M @ 02ffcac0 mfn:0xffe56
(XEN) 1ST[0x2] = 0x00000000f3f686ff
(XEN) 2ND[0x80] = 0x0000000000000000
(XEN) bad p2m lookup
(XEN) dom1 IPA 0x0000000090001000
(XEN) P2M @ 02ffcac0 mfn:0xffe56
(XEN) 1ST[0x2] = 0x00000000f3f686ff
(XEN) 2ND[0x80] = 0x0000000000000000
(XEN) bad p2m lookup
(XEN) dom1 IPA 0x0000000090001000
(XEN) P2M @ 02ffcac0 mfn:0xffe56
(XEN) 1ST[0x2] = 0x00000000f3f686ff
(XEN) 2ND[0x80] = 0x0000000000000000

and then everything  hangs with translation fault:

(XEN) DOM1: Grant tables using version 1 layout.
(XEN) DOM1: Grant table initialized
(XEN) DOM1: NET: Registered protocol family 16
(XEN) Guest data abort: Translation fault at level 2
(XEN)     gva=88808804
(XEN)     gpa=0000000090001804
(XEN)     size=2 sign=0 write=0 reg=2
(XEN)     eat=0 cm=0 s1ptw=0 dfsc=6
(XEN) dom1 IPA 0x0000000090001804
(XEN) P2M @ 02ffcac0 mfn:0xffe56
(XEN) 1ST[0x2] = 0x00000000f3f686ff
(XEN) 2ND[0x80] = 0x0000000000000000

Detailed log is attached.
Ok, i moved allocation for console and xenstore pages back in
arch_setup_meminit() like in
http://lists.xen.org/archives/html/xen-devel/2012-06/msg01340.html and
then added kernel parameter keep_bootcon in DomU  device tree file and
everything booted up to "unable to open an initial console" and unable
to mount rootfs. I still didn't learn how to deal with xenstore, hvc0,
xvda and how to boot from initramfs on ARM using xcbuild but i'll try
to understand and learn this :) So may be it's good thing to
investigate or take deep look why add_to_physmap failed in xcbuild and
why there is bad p2m lookup in xen. Log is attached.

Do you have any difference between Dom0 .config and DomU .config? Did
you just attach initrd using xc_dom_ramdisk_file() call in xcbuild?
Any special configuration of xen console/xen store?

Well, i dont mean that i'm doing everything correctly but i tried to
run it fixing/commenting as much as i can. Could you please help if
you have time? I can test new changes, sent other useful info/logs.

-- 
Best regards,
Alexey.

Attachment: fault_xcbuild-simple-Dom0+U-A15x1_07082012.log
Description: Binary data

Attachment: roots-console_xcbuild-simple-DomU-A15x1_08082012.log
Description: Binary data

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