From patchwork Mon May 18 09:22:37 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Avi Kivity X-Patchwork-Id: 24446 Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by demeter.kernel.org (8.14.2/8.14.2) with ESMTP id n4I9Pd9l026670 for ; Mon, 18 May 2009 09:25:40 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756190AbZERJXq (ORCPT ); Mon, 18 May 2009 05:23:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756229AbZERJXn (ORCPT ); Mon, 18 May 2009 05:23:43 -0400 Received: from mx2.redhat.com ([66.187.237.31]:38409 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753585AbZERJXJ (ORCPT ); Mon, 18 May 2009 05:23:09 -0400 Received: from int-mx2.corp.redhat.com (int-mx2.corp.redhat.com [172.16.27.26]) by mx2.redhat.com (8.13.8/8.13.8) with ESMTP id n4I9NBRr016905; Mon, 18 May 2009 05:23:11 -0400 Received: from ns3.rdu.redhat.com (ns3.rdu.redhat.com [10.11.255.199]) by int-mx2.corp.redhat.com (8.13.1/8.13.1) with ESMTP id n4I9N9Uu004127; Mon, 18 May 2009 05:23:10 -0400 Received: from cleopatra.tlv.redhat.com (cleopatra.tlv.redhat.com [10.35.255.11]) by ns3.rdu.redhat.com (8.13.8/8.13.8) with ESMTP id n4I9N8oV017864; Mon, 18 May 2009 05:23:09 -0400 Received: from localhost.localdomain (cleopatra.tlv.redhat.com [10.35.255.11]) by cleopatra.tlv.redhat.com (Postfix) with ESMTP id A36DFA02B2; Mon, 18 May 2009 12:23:06 +0300 (IDT) From: Avi Kivity To: linux-kernel@vger.kernel.org Cc: kvm@vger.kernel.org Subject: [PATCH 15/43] KVM: PIT: remove usage of count_load_time for channel 0 Date: Mon, 18 May 2009 12:22:37 +0300 Message-Id: <1242638585-18470-16-git-send-email-avi@redhat.com> In-Reply-To: <1242638585-18470-1-git-send-email-avi@redhat.com> References: <1242638585-18470-1-git-send-email-avi@redhat.com> X-Scanned-By: MIMEDefang 2.58 on 172.16.27.26 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Marcelo Tosatti We can infer elapsed time from hrtimer_expires_remaining. Signed-off-by: Marcelo Tosatti Signed-off-by: Avi Kivity --- arch/x86/kvm/i8254.c | 37 +++++++++++++++++++++++++++++++------ 1 files changed, 31 insertions(+), 6 deletions(-) diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c index 3eddae6..09ae841 100644 --- a/arch/x86/kvm/i8254.c +++ b/arch/x86/kvm/i8254.c @@ -98,6 +98,32 @@ static int pit_get_gate(struct kvm *kvm, int channel) return kvm->arch.vpit->pit_state.channels[channel].gate; } +static s64 __kpit_elapsed(struct kvm *kvm) +{ + s64 elapsed; + ktime_t remaining; + struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state; + + remaining = hrtimer_expires_remaining(&ps->pit_timer.timer); + if (ktime_to_ns(remaining) < 0) + remaining = ktime_set(0, 0); + + elapsed = ps->pit_timer.period; + if (ktime_to_ns(remaining) <= ps->pit_timer.period) + elapsed = ps->pit_timer.period - ktime_to_ns(remaining); + + return elapsed; +} + +static s64 kpit_elapsed(struct kvm *kvm, struct kvm_kpit_channel_state *c, + int channel) +{ + if (channel == 0) + return __kpit_elapsed(kvm); + + return ktime_to_ns(ktime_sub(ktime_get(), c->count_load_time)); +} + static int pit_get_count(struct kvm *kvm, int channel) { struct kvm_kpit_channel_state *c = @@ -107,7 +133,7 @@ static int pit_get_count(struct kvm *kvm, int channel) WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock)); - t = ktime_to_ns(ktime_sub(ktime_get(), c->count_load_time)); + t = kpit_elapsed(kvm, c, channel); d = muldiv64(t, KVM_PIT_FREQ, NSEC_PER_SEC); switch (c->mode) { @@ -137,7 +163,7 @@ static int pit_get_out(struct kvm *kvm, int channel) WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock)); - t = ktime_to_ns(ktime_sub(ktime_get(), c->count_load_time)); + t = kpit_elapsed(kvm, c, channel); d = muldiv64(t, KVM_PIT_FREQ, NSEC_PER_SEC); switch (c->mode) { @@ -208,8 +234,6 @@ static int __pit_timer_fn(struct kvm_kpit_state *ps) wake_up_interruptible(&vcpu0->wq); hrtimer_add_expires_ns(&pt->timer, pt->period); - if (pt->period) - ps->channels[0].count_load_time = ktime_get(); return (pt->period == 0 ? 0 : 1); } @@ -305,11 +329,12 @@ static void pit_load_count(struct kvm *kvm, int channel, u32 val) if (val == 0) val = 0x10000; - ps->channels[channel].count_load_time = ktime_get(); ps->channels[channel].count = val; - if (channel != 0) + if (channel != 0) { + ps->channels[channel].count_load_time = ktime_get(); return; + } /* Two types of timer * mode 1 is one shot, mode 2 is period, otherwise del timer */