From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755397Ab2K2Usu (ORCPT ); Thu, 29 Nov 2012 15:48:50 -0500 Received: from mx1.redhat.com ([209.132.183.28]:25337 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754807Ab2K2UsX (ORCPT ); Thu, 29 Nov 2012 15:48:23 -0500 Subject: [PATCH] kvm: Fix user memslot overlap check To: mtosatti@redhat.com, gleb@redhat.com From: Alex Williamson Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, xiaoguangrong@linux.vnet.ibm.com Date: Thu, 29 Nov 2012 13:48:17 -0700 Message-ID: <20121129204619.8862.77695.stgit@bling.home> User-Agent: StGit/0.16 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Prior to memory slot sorting this loop compared all of the user memory slots for overlap with new entries. With memory slot sorting, we're just checking some number of entries in the array that may or may not be user slots. Instead, walk all the slots with kvm_for_each_memslot, which has the added benefit of terminating early when we hit the first empty slot, and skip comparison to private slots. Signed-off-by: Alex Williamson Cc: stable@vger.kernel.org --- virt/kvm/kvm_main.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index be70035..cac294d 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -710,7 +710,7 @@ int __kvm_set_memory_region(struct kvm *kvm, gfn_t base_gfn; unsigned long npages; unsigned long i; - struct kvm_memory_slot *memslot; + struct kvm_memory_slot *memslot, *slot; struct kvm_memory_slot old, new; struct kvm_memslots *slots, *old_memslots; @@ -761,13 +761,11 @@ int __kvm_set_memory_region(struct kvm *kvm, /* Check for overlaps */ r = -EEXIST; - for (i = 0; i < KVM_MEMORY_SLOTS; ++i) { - struct kvm_memory_slot *s = &kvm->memslots->memslots[i]; - - if (s == memslot || !s->npages) + kvm_for_each_memslot(slot, kvm->memslots) { + if (slot->id >= KVM_MEMORY_SLOTS || slot == memslot) continue; - if (!((base_gfn + npages <= s->base_gfn) || - (base_gfn >= s->base_gfn + s->npages))) + if (!((base_gfn + npages <= slot->base_gfn) || + (base_gfn >= slot->base_gfn + slot->npages))) goto out_free; }