[PATCH] vmi: paravirt drop udelay op
authorZachary Amsden <zach@vmware.com>
Mon, 5 Mar 2007 08:30:38 +0000 (00:30 -0800)
committerLinus Torvalds <torvalds@woody.linux-foundation.org>
Mon, 5 Mar 2007 15:57:52 +0000 (07:57 -0800)
commiteda08b1befaabcdfea1a9216ae13f9065e69baa7
treed70d13c90e540357962ae5d15a7aecc5c8b0f3fa
parent9a1c13e91f100c12dcad3a1be1b12890bf32f6ff
[PATCH] vmi: paravirt drop udelay op

Not respecting udelay causes problems with any virtual hardware that is passed
through to real hardware.  This can be noticed by any device that interacts
with the real world in real time - like AP startup, which takes real time.  Or
keyboard LEDs, which should blink in real-time.  Or floppy drives, but only
when passed through to a real floppy controller on OSes which can't
sufficiently buffer the floppy commands to emulate a zero latency floppy.  Or
IDE drives, when connecting to a physical CDROM.

This was mostly a hack to get the kernel to boot faster, but it introduced a
number of misvirtualization bugs, and Alan and Pavel argued pretty strongly
against it.  We were the only client, and now want to clean up this cruft.

Signed-off-by: Zachary Amsden <zach@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
arch/i386/kernel/paravirt.c
arch/i386/kernel/smpboot.c
arch/i386/kernel/vmi.c
include/asm-i386/delay.h
include/asm-i386/paravirt.h