Re: How console data travel in Xen?

[Anthony Liguori <aliguori@us.ibm.com>]

NAHieu wrote:

>Oops, probably you missed my point: I want to know how the data go
>from low level (HW) to Xen (hypervisor), then to dom0.
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I was avoiding answering this because I'm sure that someone who's much 
smarter than me is going to jump in and correct me on this :-)

dom0 takes the keyboard interrupts just like it normally would.  I 
believe (and I may be wrong here) that in x86 the IDT is setup such that 
keyboard interrupts go directly to the dom0 kernel (since it's in ring 1).

I would imagine that in x86-64 that those interrupts have to be 
reflected back down to the guest OS.  This is almost pure speculation 
though so hopefully someone else will jump in and correct me.

>I guess it works this way: dom0 has privileged right to access to HW,
>so it can take keyboard code directly (I guess it goes thru Xen, but
>dont know exactly how?). Then from dom to domU, it works like you
>explained. Is that correct?
>
>Many thanks, Anthony.
>Hieu.
>
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