From patchwork Thu Nov 4 00:25:29 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 12602067 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 DE28EC433FE for ; Thu, 4 Nov 2021 00:27:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C9755611EF for ; Thu, 4 Nov 2021 00:27:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233005AbhKDAaT (ORCPT ); Wed, 3 Nov 2021 20:30:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52870 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233510AbhKDA3Y (ORCPT ); Wed, 3 Nov 2021 20:29:24 -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 AFE4AC061203 for ; Wed, 3 Nov 2021 17:26:47 -0700 (PDT) Received: by mail-pg1-x549.google.com with SMTP id w13-20020a63934d000000b002a2935891daso2364199pgm.15 for ; Wed, 03 Nov 2021 17:26:47 -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=eDJLgTwa4Mq+pfIoYabE+ramu2f6Q5nSW9TL6LbQQsI=; b=AwZyd1OGNd2jGC9KPlXvy0oV+JkIiHs9n78p1LAJEXYu3abpzCJ4C2qjD9WEdimC8h /U06PEKK8296gAr9y+mGJ7YU/AYB7mMLshQmjbfJT2JjYIs1QGfBkPinN0rTDsM0mJ8v y1VXf6q7OT9SnMxtkJVPvG6qnljmv27pg/hk28jYo+otmvhiKA+XTi2uKknvqQboocCi bNfT4/DvRM5KrXSU8LLRMexndgtLytkukMKS+6YJqn2ZlSHrKvNjmLuH6tB44y+OnCgy GssafhzFt1xigLvtK4LdQ29M/UL2+eLN8sYzUERpdj2aCM8q7wJx2XZ+IzRmu3TIf4VS eNLw== 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=eDJLgTwa4Mq+pfIoYabE+ramu2f6Q5nSW9TL6LbQQsI=; b=gd8dxpVlCfB2iGJK4g2e5hKFRHLt+QrsnelJXOhyJzuGk+J3axXWSCN12jBHbhEXh6 zjmEmtXNP6hm9+XKeF19oEndkObK32cJZUzo3r+n6hd9UuCt1ngpfBqFF51/Xf2GOGJB n+ivI3Dw0PeW4s0G5tN6gJG7dX4YvoTxzU55pcRtfsVwolFA8TmD5F99gR1WS5TmA9yu Pyb/U58l/KPaW/MIoHANqM0B7zIFsnPlA8/B7blyZ1oK9GBACsSNeFTe5K7GSrE1uc97 o/jAGUuB53tYea2p8UJT9tO+G17TtZPaGM0T2Iq56y7ru0UmfE15AxK0kzqYzIq4Fnor 5jRw== X-Gm-Message-State: AOAM5323MNFAybhWBKvBrWm+ezP2Z9fNSNOvdLzqgeYDvn1hgOiIW4p3 UeaU5kdGUXqM4QYFQBcWNuhPLW6Sx8w= X-Google-Smtp-Source: ABdhPJyj4rUoqs2915nhSyoqX9YGWRaiikX568lnB/vn8bpIGUoxqu2M9ISziOOEMnXgiMyENpFmkaA/Mco= X-Received: from seanjc.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:3e5]) (user=seanjc job=sendgmr) by 2002:a17:902:ab50:b0:13f:4c70:9322 with SMTP id ij16-20020a170902ab5000b0013f4c709322mr41332797plb.89.1635985607093; Wed, 03 Nov 2021 17:26:47 -0700 (PDT) Reply-To: Sean Christopherson Date: Thu, 4 Nov 2021 00:25:29 +0000 In-Reply-To: <20211104002531.1176691-1-seanjc@google.com> Message-Id: <20211104002531.1176691-29-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 28/30] KVM: Optimize overlapping memslots check 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 From: Maciej S. Szmigiero Do a quick lookup for possibly overlapping gfns when creating or moving a memslot instead of performing a linear scan of the whole memslot set. Signed-off-by: Maciej S. Szmigiero [sean: tweaked params to avoid churn in future cleanup] Signed-off-by: Sean Christopherson --- virt/kvm/kvm_main.c | 46 +++++++++++++++++++++++++++++++-------------- 1 file changed, 32 insertions(+), 14 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index d095e01838bf..d22e40225703 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1800,6 +1800,29 @@ static int kvm_set_memslot(struct kvm *kvm, return 0; } +static bool kvm_check_memslot_overlap(struct kvm_memslots *slots, int id, + gfn_t start, gfn_t end) +{ + int idx = slots->node_idx; + struct rb_node *node; + + kvm_for_each_memslot_in_gfn_range(node, slots, start, end) { + struct kvm_memory_slot *cslot; + gfn_t cend; + + cslot = container_of(node, struct kvm_memory_slot, gfn_node[idx]); + cend = cslot->base_gfn + cslot->npages; + if (cslot->id == id) + continue; + + /* kvm_for_each_in_gfn_no_more() guarantees that cslot->base_gfn < nend */ + if (cend > start) + return true; + } + + return false; +} + /* * Allocate some memory and give it an address in the guest physical address * space. @@ -1811,8 +1834,9 @@ 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, *tmp; + struct kvm_memory_slot *old; struct kvm_memory_slot new; + struct kvm_memslots *slots; enum kvm_mr_change change; int as_id, id; int r; @@ -1841,11 +1865,13 @@ int __kvm_set_memory_region(struct kvm *kvm, if (mem->guest_phys_addr + mem->memory_size < mem->guest_phys_addr) return -EINVAL; + slots = __kvm_memslots(kvm, as_id); + /* * Note, the old memslot (and the pointer itself!) may be invalidated * and/or destroyed by kvm_set_memslot(). */ - old = id_to_memslot(__kvm_memslots(kvm, as_id), id); + old = id_to_memslot(slots, id); if (!mem->memory_size) { if (!old || !old->npages) @@ -1894,18 +1920,10 @@ int __kvm_set_memory_region(struct kvm *kvm, return 0; } - if ((change == KVM_MR_CREATE) || (change == KVM_MR_MOVE)) { - int bkt; - - /* Check for overlaps */ - kvm_for_each_memslot(tmp, bkt, __kvm_memslots(kvm, as_id)) { - if (tmp->id == id) - continue; - if (!((new.base_gfn + new.npages <= tmp->base_gfn) || - (new.base_gfn >= tmp->base_gfn + tmp->npages))) - return -EEXIST; - } - } + if ((change == KVM_MR_CREATE || change == KVM_MR_MOVE) && + kvm_check_memslot_overlap(slots, id, new.base_gfn, + new.base_gfn + new.npages)) + return -EEXIST; return kvm_set_memslot(kvm, old, &new, change); }