Hi, > I was curious why the mpic_cpu_read(MPIC_INFO(CPU_WHOAMI)) was there in > the first place and if it's still needed. If it's still required, I > guess a better approach is to eliminate the call only if the kernel is > running on the KVM guest side, where the MPIC is emulated and no longer > requires a readback.
"Why not?" A mechanism being "emulated"/"virtual" or not may not necessarily be much of a distinction (if at all!). The readback might be required to properly fulfill all requirements of a full state change protocol specification, which might easily be the case for both RS(*) and virtual hardware. And especially for virtual hardware such a "readback" event might be an extremely important "end of transaction" marker which may often be needed for freeing of temporary resources etc. I'm talking out of my *ss without any MPIC specifics here (and especially not why the readback there actually is needed - if that doesn't happen to be the case for PCI Posting reasons or some such), but it's just intended as food for thought :) *) Real Silicon (rather than RL - Real Life) HTH, Andreas Mohr -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
