From patchwork Thu Nov 4 00:25:19 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 12602047 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 C6F42C433FE for ; Thu, 4 Nov 2021 00:27:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AF63660230 for ; Thu, 4 Nov 2021 00:27:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233174AbhKDAaK (ORCPT ); Wed, 3 Nov 2021 20:30:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52730 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233361AbhKDA3G (ORCPT ); Wed, 3 Nov 2021 20:29:06 -0400 Received: from mail-pg1-x549.google.com (mail-pg1-x549.google.com [IPv6:2607:f8b0:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D7C18C061205 for ; Wed, 3 Nov 2021 17:26:29 -0700 (PDT) Received: by mail-pg1-x549.google.com with SMTP id r25-20020a63a019000000b002a20656994dso2408698pge.3 for ; Wed, 03 Nov 2021 17:26:29 -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=B/9994/Gx9Iatkg8ZNN9/jYe+CyB7PuTab7AQgLiNGnLGGd02JQcRyApdxRlS8r2SI wIVkTattOa/Hl+G+HlS0Pw2vP/hbiTJVl73WbSjtCR4c+0E/IsG4l6KVAnJMR9ka+UQP AhJN2UOWAcMdW5kuu4PA75LMM2ddSo2zxLFaUKUQ5SShCgqlqnq6xvWIrBvvVKiKlAJP R6OWMoS9a1tIeQ0pb8mIWoXzvBw+F/jylzPt+CA/eOG8bFiMzVIuEL6m4Q6Y32NW+Usl PFFe0qvLcwG/Hj3RRsP//LxnRIhYbqaz2VhGIQxTuV/4Au+pd9Ve/l+6VueXt5KbZFyE Bfng== X-Gm-Message-State: AOAM533dp5apeorQJBXk1OwBPYe4EqsxDnUTUPSVKOADlarwNKYr36xh 7QRdH1+Om8I8ZNDuSihIe/dIyazZmSI= 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) Reply-To: Sean Christopherson 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: James Morse , Alexandru Elisei , Suzuki K Poulose , Atish Patra , David Hildenbrand , Cornelia Huck , Claudio Imbrenda , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-mips@vger.kernel.org, kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Ben Gardon , "Maciej S . Szmigiero" Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org 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 Reviewed-by: Maciej S. Szmigiero --- 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;