hello, my friend:

According to my research with source code of xen, i think the process is that:

first, when Guest OS is created by Xen/Domian0, it install it's IDT through "set_trap_table" hypercall.

second, during Xen/GuestOS running, all interrupt/trap will result a trap into Ring0, that is the layer of Xen.

for some trap, such as system-call, they will be dealt with directly through interrupt hardware.

For the most of other traps, they will be dealt by xen, and then dispatched to corresponding Guest OS.

in addition, there are other details to study in-depth.

2008年03月09日

房海峰

发件人： weiming

发送时间： 2008年03月09日 09:33:41

收件人： Xen Developers

抄送：

主题： [Xen-devel] how page faults are handled in paravirtualized xenguests?

Hi,

I got contradicted information about the path of page fault handling under para-virtualized linux:

1) From some web resources: page fault interruption is trapped by xen hypervisor and it then dispatches to corresponding guest OS
2) From the book "a definitive guide to xen hypervisor": when a guest is scheduled to run by hypervisor, hypervisor installes the guest's IDT (except for special interrupts like timer) to CPU. So almost all interrupts are handled by guest OS directly, bypassing the xen hypervisor.

Which one is correct? (My guess is second one because it's more efficient)

Thanks
Weiming