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OpenVZ kernel supports x86, x86_64, and IA64 architectures as of now. Below are the quick and dirty information about how to port the kernel to yet another architecture.
* UBC: need to account any platform specific VMAs created by hand in arch specific code. i.e. if there are calls of <code>insert_vma_struct() </code> this should be accounted with <code>ub_memory_charge()</code>. Didn't find such thing on sparc64.
* If there are user triggerable <code>printk()</code>'s (related to the user, not the system as a whole) better replace them with <code>ve_printk()</code>. Otherwise user can flood (DoS). minor actually.
* Call to functions <code>find_task_by_pid()</code>, <code>for_each_process() </code> and <code>do_each_thread()</code>/<code>while_each_thread() </code> should be replaced with it's counterparts - <code>find_task_by_pid_XXX()</code>, <code>for_each_process_XXX() </code> and <code>do_each_thread_XXX()</code>/<code>while_each_thread_XXX()</code>, where <code>XXX </code> is 'either <code>all' </code> or '<code>ve'</code>. 'Here <code>all' </code> means that all system processes in the system will be scanned, while '<code>ve' </code> means that only the [[VE (VPS) accessiable ]] accessible from this task (current context - <code>get_exec_env()</code>) will be visible. So you need to decide, whether the code in question is about system or user context.
* <code>task->pid </code> should be changed with <code>virt_pid(task) </code> in some places. The rule is simple: user should see only virtual pids, while kernel operate on global pids. e.g. in signals, virtual pid should be delivered to app.
* In interrupt handlers one need to set global host ([[VE0]]) context. i.e. <code>set_exec_env()</code>, <code>set_exec_ub()</code>. i.e. interrupt handlers are running in VE0 context.
* In <code>kernel_thread() </code> one needs to prohibit kernel threads in VE. mostly Mostly security related...
* <code>show_registers() </code> better to extend to show current VE.
* <code>utsname </code> should be virtualized. this This mostly means that '<code>system_utsnames' </code> should be replaced with '<code>ve_utsname'</code>. See any arch code for this.
* some Some exports will be required. e.g. <code>show_mem() </code> and probably <code>cpu_khz</code>. easyEasy.
* everything Everything else are bugfixes.
All these are straightforward and really simple, so it should take a few hours to do.
