On Tue, 2008-01-08 at 14:15 -0500, David P. Reed wrote: > Alan Cox wrote: > > The natsemi docs here say otherwise. I trust them not you. > > > As well you should. I am honestly curious (for my own satisfaction) as > to what the natsemi docs say the delay code should do (can't imagine > they say "use io port 80 because it is unused"). I don't have any
What is the outcome of this thread? Are we going to use timing based port delays, or can we finally drop these things entirely on 64-bit architectures? I a have a doubly vested interest in this, both as the owner of an affected HP dv9210us laptop and as a maintainer of paravirt code - and would like 64-bit Linux code to stop using I/O to port 0x80 in both cases (as I suspect would every other person involved with virtualization). BTW, it isn't ever safe to pass port 0x80 through to hardware from a virtual machine; some OSes use port 0x80 as a hardware available scratch register (I believe Darwin/x86 did/does this during boot). This means simultaneous execution of two virtual machines can interleave port 0x80 values or share data with a hardware provided covert channel. This means KVM should be trapping port 0x80 access, which is really expensive, or alternatively, Linux should not be using port 0x80 for timing bus access on modern (64-bit) hardware. I've tried to follow this thread, but with all the jabs, 1-ups, and obscure legacy hardware pageantry going on, it isn't clear what we're really doing. Thanks, Zach -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
