From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4E814C433E2 for ; Fri, 4 Sep 2020 10:46:10 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id 00C5320770 for ; Fri, 4 Sep 2020 10:46:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="PDUxXl55" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 00C5320770 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvmarm-bounces@lists.cs.columbia.edu Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id ADC004B37D; Fri, 4 Sep 2020 06:46:09 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Authentication-Results: mm01.cs.columbia.edu (amavisd-new); dkim=softfail (fail, message has been altered) header.i=@kernel.org Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id RE-NvO-FzbI0; Fri, 4 Sep 2020 06:46:07 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 9B0F14B386; Fri, 4 Sep 2020 06:46:06 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 92D6B4B32D for ; Fri, 4 Sep 2020 06:46:04 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id fnQAGc6cOBQ2 for ; Fri, 4 Sep 2020 06:46:03 -0400 (EDT) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id 7AC844B32B for ; Fri, 4 Sep 2020 06:46:03 -0400 (EDT) Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A4D882087C; Fri, 4 Sep 2020 10:46:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599216362; bh=mIOES2oHYEYo5N/ys71QEEfVp16YdoOph7z6Wrougfk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PDUxXl55pS8P0i2mXv8eXiPFRnDlSsjvAB+5QhghbY4LOy55VUh4gNHr+qKYIqp2C ZQ0aCYrmuGeToF3qJsRxuR0V4jHl+tYvra5QyGZkSMc84716glwQPrjmrWNUEZ56ZU zccPHA1SUcz94hNN9twx6JN82PZz34Y5Twp2LR7c= Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kE9EH-0098oH-4r; Fri, 04 Sep 2020 11:46:01 +0100 From: Marc Zyngier To: Paolo Bonzini Subject: [PATCH 2/9] KVM: arm64: pvtime: Fix potential loss of stolen time Date: Fri, 4 Sep 2020 11:45:23 +0100 Message-Id: <20200904104530.1082676-3-maz@kernel.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200904104530.1082676-1-maz@kernel.org> References: <20200904104530.1082676-1-maz@kernel.org> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: pbonzini@redhat.com, alexandru.elisei@arm.com, drjones@redhat.com, eric.auger@redhat.com, gshan@redhat.com, steven.price@arm.com, kernel-team@android.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Cc: kvm@vger.kernel.org, kernel-team@android.com, Steven Price , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu From: Andrew Jones We should only check current->sched_info.run_delay once when updating stolen time. Otherwise there's a chance there could be a change between checks that we miss (preemption disabling comes after vcpu request checks). Signed-off-by: Andrew Jones Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20200804170604.42662-3-drjones@redhat.com --- arch/arm64/kvm/pvtime.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kvm/pvtime.c b/arch/arm64/kvm/pvtime.c index c3ef4ebd6846..95f9580275b1 100644 --- a/arch/arm64/kvm/pvtime.c +++ b/arch/arm64/kvm/pvtime.c @@ -13,6 +13,7 @@ void kvm_update_stolen_time(struct kvm_vcpu *vcpu) { struct kvm *kvm = vcpu->kvm; + u64 last_steal = vcpu->arch.steal.last_steal; u64 steal; __le64 steal_le; u64 offset; @@ -24,8 +25,8 @@ void kvm_update_stolen_time(struct kvm_vcpu *vcpu) /* Let's do the local bookkeeping */ steal = vcpu->arch.steal.steal; - steal += current->sched_info.run_delay - vcpu->arch.steal.last_steal; - vcpu->arch.steal.last_steal = current->sched_info.run_delay; + vcpu->arch.steal.last_steal = READ_ONCE(current->sched_info.run_delay); + steal += vcpu->arch.steal.last_steal - last_steal; vcpu->arch.steal.steal = steal; steal_le = cpu_to_le64(steal); -- 2.27.0 _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm