Messages in this thread | | | Date | Wed, 7 Jun 2006 11:47:47 -0700 | From | Rajesh Shah <> | Subject | Re: NMI problems with Dell SMP Xeons |
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On Wed, Jun 07, 2006 at 03:18:57PM +0000, Brendan Trotter wrote: > > > I will try forcing send_IPI_allbutself() to use the mask version rather > > than the broadcast shortcut. Later tonight ... > > I've been looking into this a little - it appears that Linux tries to > use one bit per CPU in the local APIC's "logical destination register" > and that in all cases at least one bit is set for each valid CPU. As > far as I can tell sending an NMI (or any other broadcast IPI) in > logical mode with no shorthand and "destination = 0xFF" should work > fine for both "cluster mode" and "flat mode". In this case I'd also > suggest that "clear_local_APIC()" clear the destination format > register (DFR) and the logical destination register (LDR) so that it > doesn't receive broadcast NMIs if the CPU is taken offline. > I will double-check with the CPU folks, but I don't think this will do what you want it to do. If you send an NMI IPI with destination set to 0xff, I think it will interrupt all CPUs, including the non-started CPUs in the cli;hlt state. If I remember right, the destination shorthand method simply sends the interrupt on the bus with destination set to 0xff..
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