Avi Kivity wrote: > kvm will forward a virtual machine's writes to port 0x80 to the real > port. The reason is that the write is much faster than exiting and > emulating it; the difference is measurable when compiling kernels. > > Now if the cause is simply writing to port 0x80, then we must stop > doing that. But if the reason is the back-to-back writes, when we can > keep it, since the other writes will be trapped by kvm and emulated. > Do you which is the case? > As for kvm, I don't have enough info to know anything about that. Is there a test you'd like me to try?
I think you are also asking if the crash on these laptops is caused only by back-to-back writes. Actually, it doesn't seem to matter if they are back to back. I can cause the crash if the writes to 80 are very much spread out in time - it seems only to matter how many of them get executed - almost as if there is a buffer overflow. (And of course if you do back to back writes to other ports that are apparently fully unused, such as 0xED on my machine, no crash occurs). I believe (though no one seems to have confirming documentation from the chipset or motherboard vendor) that port 80 is actually functional for some unknown function on these machines. (They do respond to "in" instructions faster than a bus cycle abort does - more evidence). I searched the DSDT to see if there is any evidence of an ACPI use for this port, but found nothing. ------------------------------------------------------------------------- SF.Net email is sponsored by: Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://ad.doubleclick.net/clk;164216239;13503038;w?http://sf.net/marketplace _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
