特权指令
- 网络Privileged Instruction;Privilege Instruction
![特权指令](../cache/1400255.jpg)
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例如:企图执行一条特权指令和诸如上溢出、下溢出与除0等的算术运算陷井。
Examples are : attempts to execute a privileged instruction and arithmetic traps such as overflow , underflow , and divide by zero .
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在Intel的实现中,读写这些结构涉及到一些特权指令,要求跨嵌套堆栈的各层进行多次出入。
In Intel 's implementation , reading and writing these structures involves privileged instructions that require multiple exits and entries across the layers of the nested stack .
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试图执行一条特权指令。
Attempt to execute a priviledged instruction .
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这种方法不再需要重新编译或捕获特权指令,因为操作系统本身在虚拟化进程中会相互紧密协作。
This approach obviates the need for any recompilation or trapping because the operating systems themselves cooperate in the virtualization process .
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类似的一个例子是完全虚拟化解决方案通过运行时代码扫描来查找和重定向特权指令(用来解决特定处理器指令集的一些问题)。
A similar example is runtime code scanning used by full virtualization solutions to find and redirect privileged instructions ( to work around issues in certain processor instruction sets ) .
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特定的特权模式指令无法捕获,基于所使用的模式还可能返回不同的结果。
Certain privileged-mode instructions do not trap , and can return different results based upon the mode .
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针对这一界定原则,指出了虚拟计算环境中CPU开销的两个测量指标,即虚拟机之间进行调度时产生的CPU性能开销和由特权域代理执行某些特权指令产生的额外CPU开销。
Based on this principle , we point out two indicators to measure the CPU overhead : the overhead of scheduling between virtual machines and the additional overhead generated by the privileged domain agent executing some privileged instructions .