Re: 答复: [Xen-devel] Why using hypercall_page ?

[Wu Bingzheng <wubingzheng@xxxxxxxxx>]

I think that's the reason too. 

Thank you very much.

Wu

å 2008-10-23åç 09:31 +0800ïLi Yaqiongåéï
> As you know, the old Intel/AMD x86 cpus use INT to invoke kernel's
> service. But the newer CPUs introduce two instruction pairs:
> syscall/sysret, syscenter/sysexit. So, because the hypercall page is
> filled by Xen, it can hide the difference of this two types. Guest OS
> only take one uniform format to invoke a hypercall.
> I gusee this is the reason.
> 
> -Techie
> 
> -----éäåä-----
> åää: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
> [mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] äè Wu Bingzheng
> åéæé: 2008å10æ23æ 9:18
> æää: xen-devel@xxxxxxxxxxxxxxxxxxx
> äé: [Xen-devel] Why using hypercall_page ?
> 
> 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 $0x82
> ret
> 
> Why not invoked the hypercall directly by "int $0x82" ? What's the
> advantage of using hypercall_page?
> 
> Thanks,
> Wu
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel
> 
> 


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