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=unavailable 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 14769C2D0CD for ; Tue, 17 Dec 2019 20:41:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E23312146E for ; Tue, 17 Dec 2019 20:41:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728756AbfLQUla (ORCPT ); Tue, 17 Dec 2019 15:41:30 -0500 Received: from mga01.intel.com ([192.55.52.88]:19766 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728499AbfLQUkp (ORCPT ); Tue, 17 Dec 2019 15:40:45 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 17 Dec 2019 12:40:44 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.69,326,1571727600"; d="scan'208";a="389952629" Received: from sjchrist-coffee.jf.intel.com ([10.54.74.202]) by orsmga005.jf.intel.com with ESMTP; 17 Dec 2019 12:40:43 -0800 From: Sean Christopherson To: James Hogan , Paul Mackerras , Christian Borntraeger , Janosch Frank , Paolo Bonzini , Marc Zyngier Cc: David Hildenbrand , Cornelia Huck , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , James Morse , Julien Thierry , Suzuki K Poulose , linux-mips@vger.kernel.org, kvm-ppc@vger.kernel.org, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, Christoffer Dall , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= Subject: [PATCH v4 18/19] KVM: Dynamically size memslot array based on number of used slots Date: Tue, 17 Dec 2019 12:40:40 -0800 Message-Id: <20191217204041.10815-19-sean.j.christopherson@intel.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20191217204041.10815-1-sean.j.christopherson@intel.com> References: <20191217204041.10815-1-sean.j.christopherson@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Archived-At: List-Archive: List-Post: 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. Tested-by: Christoffer Dall Tested-by: Marc Zyngier Signed-off-by: Sean Christopherson --- include/linux/kvm_host.h | 2 +- virt/kvm/kvm_main.c | 31 ++++++++++++++++++++++++++++--- 2 files changed, 29 insertions(+), 4 deletions(-) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 49b6b457a157..eecfa1fe0fc7 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -433,11 +433,11 @@ 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[]; }; struct kvm { diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index a1566c5cee26..57926579551b 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -569,7 +569,7 @@ 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; } @@ -1081,6 +1081,32 @@ 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, struct kvm_memory_slot *old, @@ -1091,10 +1117,9 @@ 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) { /* -- 2.24.1