From: Aurelien Jarno <aurelien@aurel32.net>
Date: Fri, 25 Sep 2009 09:09:37 +0000 (+0200)
Subject: KVM: fix LAPIC timer period overflow
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=d80e68823cada7b6d850330da1edfdf8bff9e2e6;p=users%2Fdwmw2%2Flinux.git

KVM: fix LAPIC timer period overflow

Don't overflow when computing the 64-bit period from 32-bit registers.

Fixes sourceforge bug #2826486.

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Cc: stable@kernel.org
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
---

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 9c8f9018c59b0..3ca776755ae6d 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -658,7 +658,7 @@ static void start_apic_timer(struct kvm_lapic *apic)
 {
 	ktime_t now = apic->lapic_timer.timer.base->get_time();
 
-	apic->lapic_timer.period = apic_get_reg(apic, APIC_TMICT) *
+	apic->lapic_timer.period = (u64)apic_get_reg(apic, APIC_TMICT) *
 		    APIC_BUS_CYCLE_NS * apic->divide_count;
 	atomic_set(&apic->lapic_timer.pending, 0);