Messages in this thread | | | Date | Fri, 10 Aug 2007 11:51:17 -0700 | From | Jeremy Fitzhardinge <> | Subject | Re: [PATCH 23/25] [PATCH] paravirt hooks for arch initialization |
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Glauber de Oliveira Costa wrote: > On 8/9/07, Alan Cox <alan@lxorguk.ukuu.org.uk> wrote: > >>> What's the EBDA actually used for? The only place which seems to use >>> ebda_addr is in the e820 code to avoid that area as RAM. >>> >> It belongs to the firmware. >> > > Wouldn't it be better, then, to just skip this step unconditionally if > we are running a paravirtualized guest? What do we from doing it? >
It's better to make discover_ebda() quietly cope with a missing ebda for whatever reason. We could add an explicit interface to paravirt_ops to handle this one little corner, but it isn't very important, not very general and really its just clutter. Its much better to have things cope with being virtualized quietly on their own rather than hit them all with the pv_ops hammer. pv_ops is really for things where the hypervisor-specific code really has to get actively involved.
For Xen-domU and lguest, there probably won't be an ebda, but its quite likely that it will be present in some form for vmware, kvm and xen-dom0; in those cases the (presumably virtual) ebda will be put in place as it would be in the native case, eliminating the need for any special handling.
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