To invoke hypercall:
1. Not using hypercall_page:
 mov $__HYPERCALL_sched_op, %eax
 int 0ドルx82
2. Using hypercall_page:
 call hypercall_page + __HYPERCALL_sched_op * 32
Besides, using the hypercall_page, guest has to keep a page for hypercall_page.
I do not think the hypercall_page makes the thing much easier.
Is "release guest from hardcoding" the only advantage of using hypercall_page?
Thanks,
Wu
在 2008年10月23日四的 09:24 +0800，Tian, Kevin写道：
> >From: Wu Bingzheng
> >Sent: Thursday, October 23, 2008 9:18 AM
> >
> >Hello,
> >
> >I am studing Xen hypercall now. I found that hypercall is invoked via
> >hypercall_page, which is only filled with (in
> >no-hypervisor-kernel-mode ):
> >
> >mov $i, %eax
> >int 0ドルx82
> >ret
> >
> >Why not invoked the hypercall directly by "int 0ドルx82" ? What's the
> >advantage of using hypercall_page?
> >
>
> This allows guest migrated to a newer/older xen with a different
> hypercall invocation convention. Xen fills hypercall page by its
> convention, and thus release guest from hardcoding specific flow.
>
> Thanks
> Kevin
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