linux-kernel - [PATCH] KVM: x86: Use do_div for tsc deadline calculation

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Message-ID: <4E85ACFC.1090509@siemens.com>
Date:	Fri, 30 Sep 2011 13:50:20 +0200
From:	Jan Kiszka <jan.kiszka@...mens.com>
To:	Avi Kivity <avi@...hat.com>, Marcelo Tosatti <mtosatti@...hat.com>
CC:	Stephen Rothwell <sfr@...b.auug.org.au>,
	Randy Dunlap <rdunlap@...otime.net>,
	linux-next@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>,
	"kvm@...r.kernel.org" <kvm@...r.kernel.org>,
	"Liu >> \"Liu, Jinsong\"" <jinsong.liu@...el.com>,
	"Tian, Kevin" <kevin.tian@...el.com>
Subject: [PATCH] KVM: x86: Use do_div for tsc deadline calculation

Required on i386 hosts.

Signed-off-by: Jan Kiszka <jan.kiszka@...mens.com>
---
 arch/x86/kvm/lapic.c |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index f9385ec..92390dc 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -740,9 +740,10 @@ static void start_apic_timer(struct kvm_lapic *apic)
 
 		now = apic->lapic_timer.timer.base->get_time();
 		guest_tsc = kvm_x86_ops->read_l1_tsc(vcpu);
-		if (likely(tscdeadline > guest_tsc))
-			ns = (tscdeadline - guest_tsc)
-				* 1000000L / this_tsc_khz;
+		if (likely(tscdeadline > guest_tsc)) {
+			ns = (tscdeadline - guest_tsc) * 1000000ULL;
+			do_div(ns, this_tsc_khz);
+		}
 		hrtimer_start(&apic->lapic_timer.timer,
 			ktime_add_ns(now, ns), HRTIMER_MODE_ABS);
 
-- 
1.7.3.4
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