Hi Dan/Alex, Thanks for your information and advice. I will correct and resend this patch. - I remove handle_fpu_swa_for_xen(). and, - When an FP error occurs in Xen, Xen does the panic.
Best regards, Kan >> > Why do we need handle_fpu_swa_for_xen()? Xen should >> never hit an FP >> >error that requires this support. Thanks, >> >> Same as you, I think that Xen should never hit an FP error >> that requires >> this support. However, the time when FPSWA is necessary for >> Xen may come. >> Therefore I'd like to leave handle_fpu_swa_for_xen(). > >I have to disagree. An FP error that requires handling >by the FPSWA is very rare, even in applications that do >lots of floating point processing. > >Linux/ia64 does no floating point processing, Xen/x86 does >no floating point processing, and Xen/ia64 shouldn't either. >If some developer adds floating point code into Xen/x86, >guests will break. (This happened once last year -- >someone added floating point code to compute some statistics.) > >Linux/ia64 uses floating point registers only for integer >multiply/divide (and? fast copy?). The same is true of Xen/ia64. >If any Xen/ia64 developer adds any floating point code >in Xen that could possibly cause an FPSWA, I'd rather see >a panic so that code could be removed or fixed. > >Last, it is not Linux or Xen style to add code that might >possibly be used sometime in the future. A kernel and a >hypervisor should be as small as possible and adding >even a few hundred bytes of code that maybe will be >executed sometime in the future (or, in my opinion, never >should be) is bad style. At best, the code should be >surrounded by an "#if 0", and I don't think even that >is a good idea. > >Just my opinion... others may disagree. >Dan _______________________________________________ Xen-ia64-devel mailing list Xen-ia64-devel@lists.xensource.com http://lists.xensource.com/xen-ia64-devel
