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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A4409C433FE for ; Thu, 4 Nov 2021 00:26:35 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id 567D7611EE for ; Thu, 4 Nov 2021 00:26:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 567D7611EE Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.cs.columbia.edu Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 013D64B190; Wed, 3 Nov 2021 20:26:35 -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=@google.com 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 rBhWQrFc75+X; Wed, 3 Nov 2021 20:26:33 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id D6E134B1A9; Wed, 3 Nov 2021 20:26:32 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 6B04E4B13E for ; Wed, 3 Nov 2021 20:26:31 -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 Hr6vTSCLPlqI for ; Wed, 3 Nov 2021 20:26:30 -0400 (EDT) Received: from mail-pl1-f201.google.com (mail-pl1-f201.google.com [209.85.214.201]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id 1CD4B4B190 for ; Wed, 3 Nov 2021 20:26:30 -0400 (EDT) Received: by mail-pl1-f201.google.com with SMTP id q2-20020a170902dac200b001422673d86fso1025417plx.20 for ; Wed, 03 Nov 2021 17:26:30 -0700 (PDT) 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=gefeXeMu+9xCn+OiiZbsmvywIWNyuYY1aczHxfS7F84=; b=q1wAaFzQivbUaLWNpD28vIW6ok97J24IWOZtjc0+hsnIoFnhMyUWsnSfQKoqN3maJ3 KBdBMOyYnFaTKZvkOTgijuDb8a1y6dTYyIvATTjrk50gQdXgdq0sK8P9D8VXqeBwIchM S4752LKzCwKCElggFGcp/0gCfncZSwTidehk3QlNJHjH4YdWFX4NP2+qFH0XmXIojpE7 shl+78ytzLoTN1+DNy2u1aXGBjCw+SMXFRKxDeT2bHggWBTmy7o/SubcktQSj4/PZQou hwUcODvMGvNUFZIWK9EWYU9o0oSTlOaqrHSlqsc6GHFHSECGSUQyaSoW+8/pBlFiy+YJ LVDw== 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=gefeXeMu+9xCn+OiiZbsmvywIWNyuYY1aczHxfS7F84=; b=BPBTiiGnMrznh0bkAx8KEJqc+74LnnnS6tMJw4UbENBZzvlD9ulq5tVBnZxtmRcWlu Vj4wWdu3Oj7cgJ7JiM+j66/6zr+erm8fR7cIKRb95fJetriHKn+BVY6NFb5v7SEeN2J+ o5B/ntodHGyld68bdcs1FOvUHuhpPBeRT238nS4HZ94JgYSP04rBzWSYe/+9H19lG4jc 6FjZiyLZElNpUdf6qq8xjSChdn0uL+cnqNo0QiaxMsXC9GB2MqxTVB42BpB8K+HPaTOK +CmJfn90Pz83yc8255wrSo+PEH0XEZ9ZlRK7uhKNx8JQSLL8Cu1YNCQxOpA24NBIFKUk xpHQ== X-Gm-Message-State: AOAM531wu3IZmTBZQk9kKBmmtMXlCc33L9Ng8TgHE4az7orEm44k/I2M IisKuI+OCprcv5yslHXjJPGDbKcVMnk= X-Google-Smtp-Source: ABdhPJwuRHtV9T3+KFXWyLxF72TgsEexvxCX5VCcTZ2sr7WXwUborCujSIBbaHyiH9gR1LJWc7GYuxnx26s= X-Received: from seanjc.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:3e5]) (user=seanjc job=sendgmr) by 2002:a63:740e:: with SMTP id p14mr35995604pgc.329.1635985589285; Wed, 03 Nov 2021 17:26:29 -0700 (PDT) Date: Thu, 4 Nov 2021 00:25:19 +0000 In-Reply-To: <20211104002531.1176691-1-seanjc@google.com> Message-Id: <20211104002531.1176691-19-seanjc@google.com> Mime-Version: 1.0 References: <20211104002531.1176691-1-seanjc@google.com> X-Mailer: git-send-email 2.33.1.1089.g2158813163f-goog Subject: [PATCH v5.5 18/30] KVM: Don't make a full copy of the old memslot in __kvm_set_memory_region() From: Sean Christopherson To: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Paul Mackerras , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Christian Borntraeger , Janosch Frank , Paolo Bonzini Cc: Wanpeng Li , kvm@vger.kernel.org, David Hildenbrand , linux-kernel@vger.kernel.org, Atish Patra , Ben Gardon , "Maciej S . Szmigiero" , Claudio Imbrenda , linux-riscv@lists.infradead.org, Joerg Roedel , kvmarm@lists.cs.columbia.edu, kvm-ppc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Jim Mattson , Cornelia Huck , linux-mips@vger.kernel.org, kvm-riscv@lists.infradead.org, Vitaly Kuznetsov X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list Reply-To: Sean Christopherson 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 Stop making a full copy of the old memslot in __kvm_set_memory_region() now that metadata updates are handled by kvm_set_memslot(), i.e. now that the old memslot's dirty bitmap doesn't need to be referenced after the memslot and its pointer is modified/invalidated by kvm_set_memslot(). No functional change intended. Signed-off-by: Sean Christopherson --- virt/kvm/kvm_main.c | 35 +++++++++++++---------------------- 1 file changed, 13 insertions(+), 22 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 6c7bbc452dae..bbaa01afac43 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1715,8 +1715,8 @@ static int kvm_set_memslot(struct kvm *kvm, int __kvm_set_memory_region(struct kvm *kvm, const struct kvm_userspace_memory_region *mem) { - struct kvm_memory_slot old, new; - struct kvm_memory_slot *tmp; + struct kvm_memory_slot *old, *tmp; + struct kvm_memory_slot new; enum kvm_mr_change change; int as_id, id; int r; @@ -1746,25 +1746,16 @@ int __kvm_set_memory_region(struct kvm *kvm, return -EINVAL; /* - * Make a full copy of the old memslot, the pointer will become stale - * when the memslots are re-sorted by update_memslots(), and the old - * memslot needs to be referenced after calling update_memslots(), e.g. - * to free its resources and for arch specific behavior. + * Note, the old memslot (and the pointer itself!) may be invalidated + * and/or destroyed by kvm_set_memslot(). */ - tmp = id_to_memslot(__kvm_memslots(kvm, as_id), id); - if (tmp) { - old = *tmp; - tmp = NULL; - } else { - memset(&old, 0, sizeof(old)); - old.id = id; - } + old = id_to_memslot(__kvm_memslots(kvm, as_id), id); if (!mem->memory_size) { - if (!old.npages) + if (!old || !old->npages) return -EINVAL; - if (WARN_ON_ONCE(kvm->nr_memslot_pages < old.npages)) + if (WARN_ON_ONCE(kvm->nr_memslot_pages < old->npages)) return -EIO; memset(&new, 0, sizeof(new)); @@ -1784,7 +1775,7 @@ int __kvm_set_memory_region(struct kvm *kvm, if (new.npages > KVM_MEM_MAX_NR_PAGES) return -EINVAL; - if (!old.npages) { + if (!old || !old->npages) { change = KVM_MR_CREATE; /* @@ -1794,14 +1785,14 @@ int __kvm_set_memory_region(struct kvm *kvm, if ((kvm->nr_memslot_pages + new.npages) < kvm->nr_memslot_pages) return -EINVAL; } else { /* Modify an existing slot. */ - if ((new.userspace_addr != old.userspace_addr) || - (new.npages != old.npages) || - ((new.flags ^ old.flags) & KVM_MEM_READONLY)) + if ((new.userspace_addr != old->userspace_addr) || + (new.npages != old->npages) || + ((new.flags ^ old->flags) & KVM_MEM_READONLY)) return -EINVAL; - if (new.base_gfn != old.base_gfn) + if (new.base_gfn != old->base_gfn) change = KVM_MR_MOVE; - else if (new.flags != old.flags) + else if (new.flags != old->flags) change = KVM_MR_FLAGS_ONLY; else /* Nothing to change. */ return 0; -- 2.33.1.1089.g2158813163f-goog _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm