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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, 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 AA5C3CA9EB0 for ; Tue, 22 Oct 2019 00:35:52 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id 67B3922469 for ; Tue, 22 Oct 2019 00:35:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 67B3922469 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com 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 202E84A997; Mon, 21 Oct 2019 20:35:52 -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 UuJp-RnejQno; Mon, 21 Oct 2019 20:35:50 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 2EDAC4AC0D; Mon, 21 Oct 2019 20:35:45 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 27D924A993 for ; Mon, 21 Oct 2019 20:35:44 -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 n1zIf82pRTbj for ; Mon, 21 Oct 2019 20:35:43 -0400 (EDT) Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id 5067A4A9D5 for ; Mon, 21 Oct 2019 20:35:42 -0400 (EDT) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 21 Oct 2019 17:35:40 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.67,325,1566889200"; d="scan'208";a="348897241" Received: from sjchrist-coffee.jf.intel.com ([10.54.74.41]) by orsmga004.jf.intel.com with ESMTP; 21 Oct 2019 17:35:39 -0700 From: Sean Christopherson To: James Hogan , Paul Mackerras , Christian Borntraeger , Janosch Frank , Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , Marc Zyngier Subject: [PATCH v2 15/15] KVM: Dynamically size memslot array based on number of used slots Date: Mon, 21 Oct 2019 17:35:37 -0700 Message-Id: <20191022003537.13013-16-sean.j.christopherson@intel.com> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20191022003537.13013-1-sean.j.christopherson@intel.com> References: <20191022003537.13013-1-sean.j.christopherson@intel.com> MIME-Version: 1.0 Cc: linux-arm-kernel@lists.infradead.org, Wanpeng Li , kvm@vger.kernel.org, David Hildenbrand , Joerg Roedel , Cornelia Huck , linux-mips@vger.kernel.org, Sean Christopherson , linux-kernel@vger.kernel.org, kvm-ppc@vger.kernel.org, Vitaly Kuznetsov , kvmarm@lists.cs.columbia.edu, Jim Mattson 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 Now that the memslot logic doesn't assume memslots are always non-NULL, dynamically size the array of memslots instead of unconditionally allocating memory for the maximum number of memslots. Note, because a to-be-deleted memslot must first be invalidated, the array size cannot be immediately reduced when deleting a memslot. However, consecutive deletions will realize the memory savings, i.e. a second deletion will trim the entry. Signed-off-by: Sean Christopherson --- include/linux/kvm_host.h | 5 ++++- virt/kvm/kvm_main.c | 31 ++++++++++++++++++++++++++++--- 2 files changed, 32 insertions(+), 4 deletions(-) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 3f8a7760bb79..9e3a68257e80 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -433,11 +433,14 @@ static inline int kvm_arch_vcpu_memslots_id(struct kvm_vcpu *vcpu) */ struct kvm_memslots { u64 generation; - struct kvm_memory_slot memslots[KVM_MEM_SLOTS_NUM]; /* The mapping table from slot id to the index in memslots[]. */ short id_to_index[KVM_MEM_SLOTS_NUM]; atomic_t lru_slot; int used_slots; + struct kvm_memory_slot memslots[]; + /* + * WARNING: 'memslots' is dynamically-sized. It *MUST* be at the end. + */ }; struct kvm { diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 177caac395de..131b2dd7db72 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -535,7 +535,7 @@ static struct kvm_memslots *kvm_alloc_memslots(void) return NULL; for (i = 0; i < KVM_MEM_SLOTS_NUM; i++) - slots->id_to_index[i] = slots->memslots[i].id = -1; + slots->id_to_index[i] = -1; return slots; } @@ -934,6 +934,32 @@ static struct kvm_memslots *install_new_memslots(struct kvm *kvm, return old_memslots; } +/* + * Note, at a minimum, the current number of used slots must be allocated, even + * when deleting a memslot, as we need a complete duplicate of the memslots for + * use when invalidating a memslot prior to deleting/moving the memslot. + */ +static struct kvm_memslots *kvm_dup_memslots(struct kvm_memslots *old, + enum kvm_mr_change change) +{ + struct kvm_memslots *slots; + size_t old_size, new_size; + + old_size = sizeof(struct kvm_memslots) + + (sizeof(struct kvm_memory_slot) * old->used_slots); + + if (change == KVM_MR_CREATE) + new_size = old_size + sizeof(struct kvm_memory_slot); + else + new_size = old_size; + + slots = kvzalloc(new_size, GFP_KERNEL_ACCOUNT); + if (likely(slots)) + memcpy(slots, old, old_size); + + return slots; +} + static int kvm_set_memslot(struct kvm *kvm, const struct kvm_userspace_memory_region *mem, const struct kvm_memory_slot *old, @@ -944,10 +970,9 @@ static int kvm_set_memslot(struct kvm *kvm, struct kvm_memslots *slots; int r; - slots = kvzalloc(sizeof(struct kvm_memslots), GFP_KERNEL_ACCOUNT); + slots = kvm_dup_memslots(__kvm_memslots(kvm, as_id), change); if (!slots) return -ENOMEM; - memcpy(slots, __kvm_memslots(kvm, as_id), sizeof(struct kvm_memslots)); if (change == KVM_MR_DELETE || change == KVM_MR_MOVE) { /* -- 2.22.0 _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm