On Xen, we have to use /proc/iomem to retrieve the memory area for the kexec'd
kernel, not /sys/firmware/memmap. Dom0 kernel gets a E820 map that contains
only one region:
0000000000000000-0000000018e5e000 (System RAM)
Compared to the /proc/iomem:
00000000-0009cbff : System RAM
0009cc00-0009ffff : reserved
000ce000-000d3fff : reserved
000e0000-000fffff : reserved
00100000-1fd6ffff : System RAM
01000000-04ffffff : Crash kernel
1ec00000-1fbfffff : Hypervisor code and data
1f0b4680-1f0b4873 : Crash note
1f0b4900-1f0b4a93 : Crash note
1f0b4b80-1f0b4d13 : Crash note
1f0b4e00-1f0b4f93 : Crash note
...
Without that patch, /proc/vmcore is empty in the kexec'd kernel and I'm unable
to copy the crashdump.
Signed-off-by: Bernhard Walle <bwalle at suse.de>
---
kexec/arch/i386/kexec-x86-common.c | 10 +++++++++-
1 files changed, 9 insertions(+), 1 deletions(-)
diff --git a/kexec/arch/i386/kexec-x86-common.c b/kexec/arch/i386/kexec-x86-common.c
index 00c2be3..1453780 100644
--- a/kexec/arch/i386/kexec-x86-common.c
+++ b/kexec/arch/i386/kexec-x86-common.c
@@ -27,6 +27,7 @@
#include "../../kexec.h"
#include "../../kexec-syscall.h"
#include "../../firmware_memmap.h"
+#include "../../crashdump.h"
#include "kexec-x86.h"
static struct memory_range memory_range[MAX_MEMORY_RANGES];
@@ -147,7 +148,14 @@ int get_memory_ranges(struct memory_range **range, int *ranges,
{
int ret, i;
- if (have_sys_firmware_memmap())
+ /*
+ * When using Xen, /sys/firmware/memmap (i.e., the E820 map) is
+ * wrong, it just provides one large memory are and that cannot
+ * be used for Kdump. Use always the /proc/iomem interface there
+ * even if we have /sys/firmware/memmap. Without that, /proc/vmcore
+ * is empty in the kdump kernel.
+ */
+ if (!xen_present() && have_sys_firmware_memmap())
ret = get_memory_ranges_sysfs(range, ranges);
else
ret = get_memory_ranges_proc_iomem(range, ranges);
--
1.6.0.2
