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 Received: from smtp1.osuosl.org (smtp1.osuosl.org [140.211.166.138]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 545CCC433EF for ; Wed, 8 Dec 2021 01:54:52 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp1.osuosl.org (Postfix) with ESMTP id 0169982784; Wed, 8 Dec 2021 01:54:52 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp1.osuosl.org ([127.0.0.1]) by localhost (smtp1.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id k0sVYYGXdWMV; Wed, 8 Dec 2021 01:54:51 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp1.osuosl.org (Postfix) with ESMTPS id DFF25824EE; Wed, 8 Dec 2021 01:54:50 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id BEBC0C001E; Wed, 8 Dec 2021 01:54:50 +0000 (UTC) Received: from smtp4.osuosl.org (smtp4.osuosl.org [IPv6:2605:bc80:3010::137]) by lists.linuxfoundation.org (Postfix) with ESMTP id 5660AC0012 for ; Wed, 8 Dec 2021 01:54:50 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id 396AA41D74 for ; Wed, 8 Dec 2021 01:54:50 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Authentication-Results: smtp4.osuosl.org (amavisd-new); dkim=pass (2048-bit key) header.d=google.com Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id MoCnPEVuVGNz for ; Wed, 8 Dec 2021 01:54:49 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.8.0 Received: from mail-pf1-x44a.google.com (mail-pf1-x44a.google.com [IPv6:2607:f8b0:4864:20::44a]) by smtp4.osuosl.org (Postfix) with ESMTPS id AD98F41D8A for ; Wed, 8 Dec 2021 01:54:49 +0000 (UTC) Received: by mail-pf1-x44a.google.com with SMTP id a23-20020a62bd17000000b004a3f6892612so665367pff.22 for ; Tue, 07 Dec 2021 17:54:49 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=reply-to:date:in-reply-to:message-id:mime-version:references :subject:from:to:cc; bh=t+Ei0itOPUqCS4bP4MpGZr4Y0AKiyZYQUO3shvC6OH4=; b=k2YwbuxAPGemjRBHL7uFYlBdoruRLQIFroSCqiVqW7M9ZBvnUQQ9jGvvoRM5wp50BU zIgGQ7HGQFBmuNg7A+QIp+NCeTdN/K7rIpyetOEYv0fFftMX25G2HHMkN4qtIQ0LfZMv nEZ0SJpr3uyAnIWFfnfoFOuoynn+5sugfYnXc8Zu5xGttDxjBfbR1pzNtBX3wmGo5Eh4 tc+DrZgmJZQlP0JmnQUhMMdwg4C1ob1gWVBL3GTQuYBEqUYWxacTaSRVkDaRkCGPvyNC fBrkeiQfSYOSRFEFYUtRYvG8vJlWJMCUTEIGnMXeL5T96k3SQN4J7z95j0CLBBRC0fn1 ygmg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:reply-to:date:in-reply-to:message-id :mime-version:references:subject:from:to:cc; bh=t+Ei0itOPUqCS4bP4MpGZr4Y0AKiyZYQUO3shvC6OH4=; b=pNJ/e30w+8v7utV4lRkn8M+nJCJty/wKcsEeKPXfOQt70DOSxvVl1ANwot86pSlHha TrX9SL03eyT+XwUA6K9d2OHZuW9ZKc0eUDJq9bcWV8Rwp2ZroWK3IyL6VOPn2oeIsuyv wp0j80a3aiBCO0BNi9PXg9vhQee6h5BYKyUf6DEvY62WLqZZgSkXQgodumE67t5kXOMB IMUgEhhRGywIWBIJ6K0ZBdAM2hj889abLxeU8qOU8bzfrHpNEk6Y7caQt7tes45Mj7Dj yeKKwI06P6BYqCP911aQqHWYruBNpRbWTPtgKwuVojnjImoMkdeQJqKPqqlNXRcwomqs jjBA== X-Gm-Message-State: AOAM531YQ0kEHuXfebT6NrSvj1p2orzi72+THc4zQkVJnngJTkrHzDqN RJeabp0NsbOcANQSFWEuUCQXRX+aK8M= X-Google-Smtp-Source: ABdhPJydNGMZpFjjQ57G1ZC66ywbHz44PKREG9EyVwHjLHfG2SNsZYM0b6sqBp1lD+CDQVcAS7e/s6aPdYs= X-Received: from seanjc.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:3e5]) (user=seanjc job=sendgmr) by 2002:a17:90b:1486:: with SMTP id js6mr342701pjb.0.1638928488764; Tue, 07 Dec 2021 17:54:48 -0800 (PST) Date: Wed, 8 Dec 2021 01:52:11 +0000 In-Reply-To: <20211208015236.1616697-1-seanjc@google.com> Message-Id: <20211208015236.1616697-2-seanjc@google.com> Mime-Version: 1.0 References: <20211208015236.1616697-1-seanjc@google.com> X-Mailer: git-send-email 2.34.1.400.ga245620fadb-goog Subject: [PATCH v3 01/26] KVM: fix avic_set_running for preemptable kernels To: Paolo Bonzini , Joerg Roedel Cc: Wanpeng Li , kvm@vger.kernel.org, Sean Christopherson , linux-kernel@vger.kernel.org, Maxim Levitsky , iommu@lists.linux-foundation.org, Vitaly Kuznetsov , Jim Mattson X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Sean Christopherson via iommu Reply-To: Sean Christopherson Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" From: Paolo Bonzini avic_set_running() passes the current CPU to avic_vcpu_load(), albeit via vcpu->cpu rather than smp_processor_id(). If the thread is migrated while avic_set_running runs, the call to avic_vcpu_load() can use a stale value for the processor id. Avoid this by blocking preemption over the entire execution of avic_set_running(). Reported-by: Sean Christopherson Signed-off-by: Paolo Bonzini Reviewed-by: Maxim Levitsky Not-signed-off-by: Sean Christopherson --- arch/x86/kvm/svm/avic.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c index 1d8ada5b01f8..d7132a4551a2 100644 --- a/arch/x86/kvm/svm/avic.c +++ b/arch/x86/kvm/svm/avic.c @@ -997,16 +997,18 @@ void avic_vcpu_put(struct kvm_vcpu *vcpu) static void avic_set_running(struct kvm_vcpu *vcpu, bool is_run) { struct vcpu_svm *svm = to_svm(vcpu); + int cpu = get_cpu(); + WARN_ON(cpu != vcpu->cpu); svm->avic_is_running = is_run; - if (!kvm_vcpu_apicv_active(vcpu)) - return; - - if (is_run) - avic_vcpu_load(vcpu, vcpu->cpu); - else - avic_vcpu_put(vcpu); + if (kvm_vcpu_apicv_active(vcpu)) { + if (is_run) + avic_vcpu_load(vcpu, cpu); + else + avic_vcpu_put(vcpu); + } + put_cpu(); } void svm_vcpu_blocking(struct kvm_vcpu *vcpu) -- 2.34.1.400.ga245620fadb-goog _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu