Juergen Gross ab24507cfa xen: avoid another early crash of memory limited dom0 ... Commit b1c9f169047b ("xen: split counting of extra memory pages...") introduced an error when dom0 was started with limited memory occurring only on some hardware. The problem arises in case dom0 is started with initial memory and maximum memory being the same. The kernel must be configured without CONFIG_XEN_BALLOON_MEMORY_HOTPLUG for the problem to happen. If all of this is true and the E820 map of the machine is sparse (some areas are not covered) then the machine might crash early in the boot process. An example E820 map triggering the problem looks like this: [ 0.000000] e820: BIOS-provided physical RAM map: [ 0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009d7ff] usable [ 0.000000] BIOS-e820: [mem 0x000000000009d800-0x000000000009ffff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000000e0000-0x00000000000fffff] reserved [ 0.000000] BIOS-e820: [mem 0x0000000000100000-0x00000000cf7fafff] usable [ 0.000000] BIOS-e820: [mem 0x00000000cf7fb000-0x00000000cf95ffff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000cf960000-0x00000000cfb62fff] ACPI NVS [ 0.000000] BIOS-e820: [mem 0x00000000cfb63000-0x00000000cfd14fff] usable [ 0.000000] BIOS-e820: [mem 0x00000000cfd15000-0x00000000cfd61fff] ACPI NVS [ 0.000000] BIOS-e820: [mem 0x00000000cfd62000-0x00000000cfd6cfff] ACPI data [ 0.000000] BIOS-e820: [mem 0x00000000cfd6d000-0x00000000cfd6ffff] ACPI NVS [ 0.000000] BIOS-e820: [mem 0x00000000cfd70000-0x00000000cfd70fff] usable [ 0.000000] BIOS-e820: [mem 0x00000000cfd71000-0x00000000cfea8fff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000cfea9000-0x00000000cfeb9fff] ACPI NVS [ 0.000000] BIOS-e820: [mem 0x00000000cfeba000-0x00000000cfecafff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000cfecb000-0x00000000cfecbfff] ACPI NVS [ 0.000000] BIOS-e820: [mem 0x00000000cfecc000-0x00000000cfedbfff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000cfedc000-0x00000000cfedcfff] ACPI NVS [ 0.000000] BIOS-e820: [mem 0x00000000cfedd000-0x00000000cfeddfff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000cfede000-0x00000000cfee3fff] ACPI NVS [ 0.000000] BIOS-e820: [mem 0x00000000cfee4000-0x00000000cfef6fff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000cfef7000-0x00000000cfefffff] usable [ 0.000000] BIOS-e820: [mem 0x00000000e0000000-0x00000000efffffff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000fec00000-0x00000000fec00fff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000fec10000-0x00000000fec10fff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000fed00000-0x00000000fed00fff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000fed40000-0x00000000fed44fff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000fed61000-0x00000000fed70fff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000fed80000-0x00000000fed8ffff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000ff000000-0x00000000ffffffff] reserved [ 0.000000] BIOS-e820: [mem 0x0000000100001000-0x000000020effffff] usable In this case the area a0000-dffff isn't present in the map. This will confuse the memory setup of the domain when remapping the memory from such holes to populated areas. To avoid the problem the accounting of to be remapped memory has to count such holes in the E820 map as well. Reported-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>		2015-09-08 16:28:04 +01:00
..
boot	x86/efi: Use all 64 bit of efi_memmap in setup_e820()	2015-07-30 18:07:10 +01:00
configs
crypto
entry	x86: fix error handling for 32-bit compat out-of-range system call numbers	2015-08-13 16:19:44 -07:00
ia32
include	xen/PMU: Initialization code for Xen PMU	2015-08-20 12:25:20 +01:00
kernel	Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2015-08-16 15:11:25 -07:00
kvm	KVM: x86: Use adjustment in guest cycles when handling MSR_IA32_TSC_ADJUST	2015-08-07 13:28:03 +02:00
lguest
lib	perf/x86: Fix copy_from_user_nmi() return if range is not ok	2015-07-06 14:09:27 +02:00
math-emu	x86/ldt: Further fix FPU emulation	2015-08-16 15:11:05 -07:00
mm	x86/mm/pat: Revert 'Adjust default caching mode translation tables'	2015-07-26 10:27:37 +02:00
net	ebpf, x86: fix general protection fault when tail call is invoked	2015-07-29 17:02:19 -07:00
oprofile
pci
platform	efi: Check for NULL efi kernel parameters	2015-07-30 18:07:11 +01:00
power	x86/ldt: Make modify_ldt synchronous	2015-07-31 10:23:23 +02:00
purgatory
realmode
tools
um
video
xen	xen: avoid another early crash of memory limited dom0	2015-09-08 16:28:04 +01:00
.gitignore
Kbuild
Kconfig	x86/fpu, sched: Introduce CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT and use it on x86	2015-07-18 03:42:51 +02:00
Kconfig.cpu
Kconfig.debug	x86/entry/64, x86/nmi/64: Add CONFIG_DEBUG_ENTRY NMI testing code	2015-07-17 12:50:14 +02:00
Makefile
Makefile_32.cpu
Makefile.um