Hi, as some of you may be aware I am working on porting kexec to xen/ia64. I have made a reasoble ammount of progress to this end. I'll try and get a new patch set on xen-devel some time next week. However I have a problem that I need some ideas on how to solve. At the moment when kexecing from xen to linux the boot halts on a call to efi_gettimeofday(), or more specifically efi.get_time. I'm assuming that this is more or less the first efi runtime call that is made, and that it is halting because of a discrepancy in the virtual mapping set up by efi.set_virtual_address_map(). The problem as I see it is that linux uses a page_offset that covers the most significant 3 bits, wherase xen uses the first 4. The unfortunate thing is that efi.set_virtual_address_map() can only be called once, and I don't think its possible to change the mappings at all once its been called. One idea that I had was to make sure that the efi calls are always made in real mode, and never call efi.set_virtual_address_map() at all - efi calls have to be made using virtual addressing after efi.set_virtual_address_map() is called. But can this work? Another idea from my colleague Magnus was to map the efi runtime calls into some area of memory that is agreed upon by both Linux and Xen (and any other kexec-able OS/hypervisor). This seems to be tedious at best. And a last idea was to replace the efi table with our own calls, much the same way that xen provideds a virtualised efi table to its domains. However I'm really not sure if this is possible, as it seems that at best such functions would be a mechanism to implement the real-mode approach. I'd really appreciate some input on whether or not the problem that I think I am seeing is plausible. And if so, is there a decent way around it? -- Horms H: http://www.vergenet.net/~horms/ W: http://www.valinux.co.jp/en/ - To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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