Avi Kivity wrote: > On 09/09/2012 05:54 PM, Liu, Jinsong wrote: >>> >>> hrtimers is an intrusive feature, I don't think we should >>> force-enable it. Please change it to a depends on. >> >> Hmm, if it changed as >> config KVM >> depends on HIGH_RES_TIMERS >> The item 'Kernel-based Virtual Machine (KVM) support (NEW)' even >> didn't appear to user when make menuconfig (when HIGH_RES_TIMERS >> disable) >> >> Is it good? I just have a little concern here:) > > It's not good, but that's what we have. > > It's okay to force-enable low-impact features (like preempt notifies). > > hrimers, on the other hand, change kernel behaviour quite deeply. > > Maybe over time someone will fix the config tools to unhide features > that can be enabled by turning on a dependency.
OK, updated as attached.
Thanks,
Jinsong
===============
>From e6c2a80d3111cc6fb992d78b242619706d99bc6b Mon Sep 17 00:00:00 2001
From: Liu, Jinsong <jinsong....@intel.com>
Date: Mon, 10 Sep 2012 06:55:39 +0800
Subject: [PATCH] KVM: KVM enable depends on HIGH_RES_TIMERS
KVM lapic timer and tsc deadline timer based on hrtimer,
setting a leftmost node to rb tree and then do hrtimer reprogram.
If hrtimer not configured as high resolution, hrtimer_enqueue_reprogram
do nothing and then make kvm lapic timer and tsc deadline timer fail.
Signed-off-by: Liu, Jinsong <jinsong....@intel.com>
---
arch/x86/kvm/Kconfig | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index a28f338..65657ec 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -20,6 +20,7 @@ if VIRTUALIZATION
config KVM
tristate "Kernel-based Virtual Machine (KVM) support"
depends on HAVE_KVM
+ depends on HIGH_RES_TIMERS
# for device assignment:
depends on PCI
# for TASKSTATS/TASK_DELAY_ACCT:
--
1.7.1
0001-KVM-KVM-enable-depends-on-HIGH_RES_TIMERS.patch
Description: 0001-KVM-KVM-enable-depends-on-HIGH_RES_TIMERS.patch
