From patchwork Tue Nov 30 21:41:41 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Maciej S. Szmigiero" X-Patchwork-Id: 12648231 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BD17CC433F5 for ; Tue, 30 Nov 2021 21:46:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233150AbhK3Vth (ORCPT ); Tue, 30 Nov 2021 16:49:37 -0500 Received: from vps-vb.mhejs.net ([37.28.154.113]:56940 "EHLO vps-vb.mhejs.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344754AbhK3Vsm (ORCPT ); Tue, 30 Nov 2021 16:48:42 -0500 Received: from MUA by vps-vb.mhejs.net with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1msAvC-0006Gr-6E; Tue, 30 Nov 2021 22:44:18 +0100 From: "Maciej S. Szmigiero" To: Paolo Bonzini , Sean Christopherson Cc: Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Igor Mammedov , Marc Zyngier , James Morse , Julien Thierry , Suzuki K Poulose , Huacai Chen , Aleksandar Markovic , Paul Mackerras , Christian Borntraeger , Janosch Frank , David Hildenbrand , Cornelia Huck , Claudio Imbrenda , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandru Elisei , Atish Patra , Ben Gardon , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v6 28/29] KVM: Wait 'til the bitter end to initialize the "new" memslot Date: Tue, 30 Nov 2021 22:41:41 +0100 Message-Id: X-Mailer: git-send-email 2.33.0 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Sean Christopherson Initialize the "new" memslot in the !DELETE path only after the various sanity checks have passed. This will allow a future commit to allocate @new dynamically without having to copy a memslot, and without having to deal with freeing @new in error paths and in the "nothing to change" path that's hiding in the sanity checks. No functional change intended. Signed-off-by: Sean Christopherson Reviewed-by: Maciej S. Szmigiero Signed-off-by: Maciej S. Szmigiero --- virt/kvm/kvm_main.c | 37 ++++++++++++++++++++----------------- 1 file changed, 20 insertions(+), 17 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 52117f65bc5b..8295d87c07b5 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1844,6 +1844,8 @@ int __kvm_set_memory_region(struct kvm *kvm, struct kvm_memory_slot new; struct kvm_memslots *slots; enum kvm_mr_change change; + unsigned long npages; + gfn_t base_gfn; int as_id, id; int r; @@ -1870,6 +1872,8 @@ int __kvm_set_memory_region(struct kvm *kvm, return -EINVAL; if (mem->guest_phys_addr + mem->memory_size < mem->guest_phys_addr) return -EINVAL; + if ((mem->memory_size >> PAGE_SHIFT) > KVM_MEM_MAX_NR_PAGES) + return -EINVAL; slots = __kvm_memslots(kvm, as_id); @@ -1893,15 +1897,8 @@ int __kvm_set_memory_region(struct kvm *kvm, return kvm_set_memslot(kvm, old, &new, KVM_MR_DELETE); } - new.as_id = as_id; - new.id = id; - new.base_gfn = mem->guest_phys_addr >> PAGE_SHIFT; - new.npages = mem->memory_size >> PAGE_SHIFT; - new.flags = mem->flags; - new.userspace_addr = mem->userspace_addr; - - if (new.npages > KVM_MEM_MAX_NR_PAGES) - return -EINVAL; + base_gfn = (mem->guest_phys_addr >> PAGE_SHIFT); + npages = (mem->memory_size >> PAGE_SHIFT); if (!old || !old->npages) { change = KVM_MR_CREATE; @@ -1910,27 +1907,33 @@ int __kvm_set_memory_region(struct kvm *kvm, * To simplify KVM internals, the total number of pages across * all memslots must fit in an unsigned long. */ - if ((kvm->nr_memslot_pages + new.npages) < kvm->nr_memslot_pages) + if ((kvm->nr_memslot_pages + npages) < kvm->nr_memslot_pages) return -EINVAL; } else { /* Modify an existing slot. */ - if ((new.userspace_addr != old->userspace_addr) || - (new.npages != old->npages) || - ((new.flags ^ old->flags) & KVM_MEM_READONLY)) + if ((mem->userspace_addr != old->userspace_addr) || + (npages != old->npages) || + ((mem->flags ^ old->flags) & KVM_MEM_READONLY)) return -EINVAL; - if (new.base_gfn != old->base_gfn) + if (base_gfn != old->base_gfn) change = KVM_MR_MOVE; - else if (new.flags != old->flags) + else if (mem->flags != old->flags) change = KVM_MR_FLAGS_ONLY; else /* Nothing to change. */ return 0; } if ((change == KVM_MR_CREATE || change == KVM_MR_MOVE) && - kvm_check_memslot_overlap(slots, id, new.base_gfn, - new.base_gfn + new.npages)) + kvm_check_memslot_overlap(slots, id, base_gfn, base_gfn + npages)) return -EEXIST; + new.as_id = as_id; + new.id = id; + new.base_gfn = base_gfn; + new.npages = npages; + new.flags = mem->flags; + new.userspace_addr = mem->userspace_addr; + return kvm_set_memslot(kvm, old, &new, change); } EXPORT_SYMBOL_GPL(__kvm_set_memory_region);