mirror of
https://github.com/xen-project/xen.git
synced 2026-10-28 18:21:39 +01:00
Andrew Cooper
3355c1a2a6
On 64bit Xen with 32bit dom0 and crashkernel, xmalloc'ing items such as the CPU crash notes will go into the xenheap, which tends to be in upper memory. This causes problems on machines with more than 64GB (or 4GB if no PAE support) of ram as the crashkernel physically cant access the crash notes. The solution is to force Xen to allocate certain structures in lower memory. This is achieved by introducing two new command line parameters; low_crashinfo and crashinfo_maxaddr. Because of the potential impact on 32bit PV guests, and that this problem does not exist for 64bit dom0 on 64bit Xen, this new functionality defaults to the codebase's previous behavior, requiring the user to explicitly add extra command line parameters to change the behavior. This patch consists of 3 logically distinct but closely related changes. 1) Add the two new command line parameters. 2) Change crash note allocation to use lower memory when instructed. 3) Change the conring buffer to use lower memory when instructed. There result is that the crash notes and console ring will be placed in lower memory so useful information can be recovered in the case of a crash. Changes since v1: - Patch xen-command-line.markdown to document new options Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Committed-by: Keir Fraser <keir@xen.org>
xen-bugtool =========== The xen-bugtool command line application will collate the Xen dmesg output, details of the hardware configuration of your machine, information about the build of Xen that you are using, plus, if you allow it, various logs. The information collated can either be posted to a Xen Bugzilla bug (this bug must already exist in the system, and you must be a registered user there), or it can be saved as a .tar.bz2 for sending or archiving. The collated logs may contain private information, and if you are at all worried about that, you should not use this tool, or you should explicitly exclude those logs from the archive. xen-bugtool is wholly interactive, so simply run it, and answer the questions.