From patchwork Tue Apr 16 20:32:47 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 10904169 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6F03C922 for ; Tue, 16 Apr 2019 20:32:57 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 55E67289FF for ; Tue, 16 Apr 2019 20:32:57 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4736A28A0F; Tue, 16 Apr 2019 20:32:57 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id DE04128A0B for ; Tue, 16 Apr 2019 20:32:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730677AbfDPUcx (ORCPT ); Tue, 16 Apr 2019 16:32:53 -0400 Received: from mga17.intel.com ([192.55.52.151]:46669 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730521AbfDPUcv (ORCPT ); Tue, 16 Apr 2019 16:32:51 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga107.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 16 Apr 2019 13:32:51 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,359,1549958400"; d="scan'208";a="338087378" Received: from sjchrist-coffee.jf.intel.com ([10.54.74.181]) by fmsmga006.fm.intel.com with ESMTP; 16 Apr 2019 13:32:51 -0700 From: Sean Christopherson To: Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= Cc: kvm@vger.kernel.org, Liran Alon , Wanpeng Li Subject: [PATCH v3 8/9] KVM: lapic: Check for a pending timer intr prior to start_hv_timer() Date: Tue, 16 Apr 2019 13:32:47 -0700 Message-Id: <20190416203248.29429-9-sean.j.christopherson@intel.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190416203248.29429-1-sean.j.christopherson@intel.com> References: <20190416203248.29429-1-sean.j.christopherson@intel.com> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Checking for a pending non-periodic interrupt in start_hv_timer() leads to restart_apic_timer() making an unnecessary call to start_sw_timer() due to start_hv_timer() returning false. Alternatively, start_hv_timer() could return %true when there is a pending non-periodic interrupt, but that approach is less intuitive, i.e. would require a beefy comment to explain an otherwise simple check. Cc: Liran Alon Cc: Wanpeng Li Suggested-by: Liran Alon Suggested-by: Paolo Bonzini Signed-off-by: Sean Christopherson --- arch/x86/kvm/lapic.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 9a09a41000c3..32b05ca2f70a 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -1688,9 +1688,6 @@ static bool start_hv_timer(struct kvm_lapic *apic) if (!kvm_x86_ops->set_hv_timer) return false; - if (!apic_lvtt_period(apic) && atomic_read(&ktimer->pending)) - return false; - if (!ktimer->tscdeadline) return false; @@ -1743,8 +1740,13 @@ static void start_sw_timer(struct kvm_lapic *apic) static void restart_apic_timer(struct kvm_lapic *apic) { preempt_disable(); + + if (!apic_lvtt_period(apic) && atomic_read(&apic->lapic_timer.pending)) + goto out; + if (!start_hv_timer(apic)) start_sw_timer(apic); +out: preempt_enable(); }