From patchwork Tue Feb 18 21:07:26 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 1240350 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=kvm-ppc-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=intel.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 48MYPJ1cHdz9sTV for ; Wed, 19 Feb 2020 08:08:52 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727476AbgBRVHv (ORCPT ); Tue, 18 Feb 2020 16:07:51 -0500 Received: from mga07.intel.com ([134.134.136.100]:6399 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727329AbgBRVHu (ORCPT ); Tue, 18 Feb 2020 16:07:50 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 18 Feb 2020 13:07:45 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,457,1574150400"; d="scan'208";a="253856435" Received: from sjchrist-coffee.jf.intel.com ([10.54.74.202]) by orsmga002.jf.intel.com with ESMTP; 18 Feb 2020 13:07:45 -0800 From: Sean Christopherson To: Paolo Bonzini Cc: Paul Mackerras , Christian Borntraeger , Janosch Frank , David Hildenbrand , Cornelia Huck , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Marc Zyngier , James Morse , Julien Thierry , Suzuki K Poulose , linux-mips@vger.kernel.org, kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, Christoffer Dall , Peter Xu , =?utf-8?q?Philippe_Mathieu-Daud?= =?utf-8?b?w6k=?= Subject: [PATCH v6 12/22] KVM: Move memslot deletion to helper function Date: Tue, 18 Feb 2020 13:07:26 -0800 Message-Id: <20200218210736.16432-13-sean.j.christopherson@intel.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200218210736.16432-1-sean.j.christopherson@intel.com> References: <20200218210736.16432-1-sean.j.christopherson@intel.com> MIME-Version: 1.0 Sender: kvm-ppc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm-ppc@vger.kernel.org Move memslot deletion into its own routine so that the success path for other memslot updates does not need to use kvm_free_memslot(), i.e. can explicitly destroy the dirty bitmap when necessary. This paves the way for dropping @dont from kvm_free_memslot(), i.e. all callers now pass NULL for @dont. Add a comment above the code to make a copy of the existing memslot prior to deletion, it is not at all obvious that the pointer will become stale during sorting and/or installation of new memslots. Note, kvm_arch_commit_memory_region() allows an architecture to free resources when moving a memslot or changing its flags, e.g. x86 frees its arch specific memslot metadata during commit_memory_region(). Acked-by: Christoffer Dall Tested-by: Christoffer Dall Reviewed-by: Peter Xu Signed-off-by: Sean Christopherson --- virt/kvm/kvm_main.c | 75 +++++++++++++++++++++++++++------------------ 1 file changed, 46 insertions(+), 29 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index f84bb0442a1b..1f56a0d042a0 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1043,6 +1043,27 @@ static int kvm_set_memslot(struct kvm *kvm, return r; } +static int kvm_delete_memslot(struct kvm *kvm, + const struct kvm_userspace_memory_region *mem, + struct kvm_memory_slot *old, int as_id) +{ + struct kvm_memory_slot new; + int r; + + if (!old->npages) + return -EINVAL; + + memset(&new, 0, sizeof(new)); + new.id = old->id; + + r = kvm_set_memslot(kvm, mem, old, &new, as_id, KVM_MR_DELETE); + if (r) + return r; + + kvm_free_memslot(kvm, old, NULL); + return 0; +} + /* * Allocate some memory and give it an address in the guest physical address * space. @@ -1092,7 +1113,17 @@ int __kvm_set_memory_region(struct kvm *kvm, if (npages > KVM_MEM_MAX_NR_PAGES) return -EINVAL; - new = old = *slot; + /* + * 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. + */ + old = *slot; + if (!mem->memory_size) + return kvm_delete_memslot(kvm, mem, &old, as_id); + + new = old; new.id = id; new.base_gfn = base_gfn; @@ -1100,29 +1131,20 @@ int __kvm_set_memory_region(struct kvm *kvm, new.flags = mem->flags; new.userspace_addr = mem->userspace_addr; - if (npages) { - if (!old.npages) - change = KVM_MR_CREATE; - else { /* Modify an existing slot. */ - if ((new.userspace_addr != old.userspace_addr) || - (npages != old.npages) || - ((new.flags ^ old.flags) & KVM_MEM_READONLY)) - return -EINVAL; - - if (base_gfn != old.base_gfn) - change = KVM_MR_MOVE; - else if (new.flags != old.flags) - change = KVM_MR_FLAGS_ONLY; - else /* Nothing to change. */ - return 0; - } - } else { - if (!old.npages) + if (!old.npages) { + change = KVM_MR_CREATE; + } else { /* Modify an existing slot. */ + if ((new.userspace_addr != old.userspace_addr) || + (npages != old.npages) || + ((new.flags ^ old.flags) & KVM_MEM_READONLY)) return -EINVAL; - change = KVM_MR_DELETE; - new.base_gfn = 0; - new.flags = 0; + if (base_gfn != old.base_gfn) + change = KVM_MR_MOVE; + else if (new.flags != old.flags) + change = KVM_MR_FLAGS_ONLY; + else /* Nothing to change. */ + return 0; } if ((change == KVM_MR_CREATE) || (change == KVM_MR_MOVE)) { @@ -1145,17 +1167,12 @@ int __kvm_set_memory_region(struct kvm *kvm, return r; } - /* actual memory is freed via old in kvm_free_memslot below */ - if (change == KVM_MR_DELETE) { - new.dirty_bitmap = NULL; - memset(&new.arch, 0, sizeof(new.arch)); - } - r = kvm_set_memslot(kvm, mem, &old, &new, as_id, change); if (r) goto out_bitmap; - kvm_free_memslot(kvm, &old, &new); + if (old.dirty_bitmap && !new.dirty_bitmap) + kvm_destroy_dirty_bitmap(&old); return 0; out_bitmap: