Evolution in Kernel Debugging using Hardware Virtualization With Xen

Short Description
Xen’s ability to run unmodified guests with the virtualization available in hardware opens new doors of possibilities in the kernel debugging. Now it’s possible to debug the Linux kernel or any other PC operating system similar to debugging a user process in Linux. Since hardware virtualization in-processor enables Xen to implement full virtualization of a guest OS, there is no need to change the kernel in any way to debug it.

Website: www.kernel.org | Filesize: 183kb
No of Page(s): 18

Content
The Xen[1] open source virtual machine monitor initially started with software virtualization by modifying the guest OS kernel. Since Xen 3.0, it also supports the Intel Virtualization Technology [2] to create and run unmodified guests. This Xen capability to run unmodified Linux OS or any other unmodified OS also provides a new opportunity to debug an unmodified OS using the Xen VMM. With this guest debug capability, it is possible to trap into an unmodified guest such as any Linux, Windows, DOS, or any other PC OS; and check the register state, modify registers, set debug breakpoints anywhere including in the kernel, read and write memory, or inspect or modify the code currently being executed. This new method uses gdb[3] as the front end for debugging. With gdb also comes the sourcelevel debugging of an unmodified Linux kernel. There are some advantages of using this debug approach compared to other kernel debug options, such as the Linux kernel stays unmodified, and ability of setting of breakpoints anywhere in the code. In fact it is also possible to set breakpoints in the boot loader such as grub [4] or inside the guest BIOS code.
…

Get the file Download here