tmp_suning_uos_patched/arch/x86/xen
Stefan Bader 8e1b4cf210 xen: p2m: correctly initialize partial p2m leaf
After changing the p2m mapping to a tree by

  commit 58e05027b5
    xen: convert p2m to a 3 level tree

and trying to boot a DomU with 615MB of memory, the following crash was
observed in the dump:

kernel direct mapping tables up to 26f00000 @ 1ec4000-1fff000
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<c0107397>] xen_set_pte+0x27/0x60
*pdpt = 0000000000000000 *pde = 0000000000000000

Adding further debug statements showed that when trying to set up
pfn=0x26700 the returned mapping was invalid.

pfn=0x266ff calling set_pte(0xc1fe77f8, 0x6b3003)
pfn=0x26700 calling set_pte(0xc1fe7800, 0x3)

Although the last_pfn obtained from the startup info is 0x26700, which
should in turn not be hit, the additional 8MB which are added as extra
memory normally seem to be ok. This lead to looking into the initial
p2m tree construction, which uses the smaller value and assuming that
there is other code handling the extra memory.

When the p2m tree is set up, the leaves are directly pointed to the
array which the domain builder set up. But if the mapping is not on a
boundary that fits into one p2m page, this will result in the last leaf
being only partially valid. And as the invalid entries are not
initialized in that case, things go badly wrong.

I am trying to fix that by checking whether the current leaf is a
complete map and if not, allocate a completely new page and copy only
the valid pointers there. This may not be the most efficient or elegant
solution, but at least it seems to allow me booting DomUs with memory
assignments all over the range.

BugLink: http://bugs.launchpad.net/bugs/686692
[v2: Redid a bit of commit wording and fixed a compile warning]

Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-01-21 11:24:14 -05:00
..
debugfs.c llseek: automatically add .llseek fop 2010-10-15 15:53:27 +02:00
debugfs.h xen: add debugfs support 2008-08-21 13:52:58 +02:00
enlighten.c Merge branch 'stable/bug-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen 2011-01-10 08:48:46 -08:00
grant-table.c xen: make grant table arch portable 2008-04-24 23:57:32 +02:00
irq.c xen: fix non-ANSI function warning in irq.c 2011-01-20 14:52:13 -05:00
Kconfig Merge branch 'stable/xen-pcifront-0.8.2' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen 2010-10-28 17:11:17 -07:00
Makefile xen: move p2m handling to separate file 2011-01-11 14:31:07 -05:00
mmu.c xen: export arbitrary_virt_to_machine 2011-01-14 16:11:12 -08:00
mmu.h xen: make install_p2mtop_page() static 2010-10-22 12:57:23 -07:00
multicalls.c x86, xen: do multicall callbacks with interrupts disabled 2009-02-16 08:56:41 +01:00
multicalls.h xen: Use this_cpu_ops 2010-12-17 15:07:19 +01:00
p2m.c xen: p2m: correctly initialize partial p2m leaf 2011-01-21 11:24:14 -05:00
pci-swiotlb-xen.c Merge branch 'stable/xen-pcifront-0.8.2' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen 2010-10-28 17:11:17 -07:00
platform-pci-unplug.c xen: unplug the emulated devices at resume time 2010-12-02 14:40:53 +00:00
setup.c Merge branches 'upstream/core' and 'upstream/bugfix' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen 2010-12-03 10:08:52 -08:00
smp.c Merge branch 'stable/xen-pcifront-0.8.2' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen 2010-10-28 17:11:17 -07:00
spinlock.c xen: Use this_cpu_ops 2010-12-17 15:07:19 +01:00
suspend.c xen: unplug the emulated devices at resume time 2010-12-02 14:40:53 +00:00
time.c Merge branch 'this_cpu_ops' into for-2.6.38 2010-12-17 15:16:46 +01:00
vdso.h i386: move xen 2007-10-11 11:16:51 +02:00
xen-asm_32.S percpu: remove per_cpu__ prefix. 2009-10-29 22:34:15 +09:00
xen-asm_64.S xen: use iret for return from 64b kernel to 32b usermode 2009-12-03 11:14:54 -08:00
xen-asm.h xen: make direct versions of irq_enable/disable/save/restore to common code 2009-02-04 16:59:04 -08:00
xen-asm.S x86: style cleanups for xen assemblies 2009-02-05 20:25:41 +01:00
xen-head.S x86: use _types.h headers in asm where available 2009-02-13 11:35:01 -08:00
xen-ops.h xen: unplug the emulated devices at resume time 2010-12-02 14:40:53 +00:00