From patchwork Tue Dec 17 20:40:34 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 11298701 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 08DE614E3 for ; Tue, 17 Dec 2019 20:43:40 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D75D02053B for ; Tue, 17 Dec 2019 20:43:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="IJcCCAWX" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D75D02053B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=uqcQIPe8wZSzh8I+8l3VTBqVkOLSbkH+Ww3q+pmIeps=; b=IJcCCAWXl71eli AiOajtXg2rV7wNIRJTfieQL3gaSu0knodXQLOKW7kHO1DQwAcqcpVXdbbNvO5YfrIAwkTMYR+PXn0 d7BypU9QZ0wrr0crgfK5Y7BtAGGwrGCc4hXG4797tr/s06Ji6CD3/NhsdyPZvJ2zE9tJbunUdwmba EMWC0hemlQfZiSWMBGl3JgZbd5rNaA2/UZOg/7hAj8GiX+XOF2SBmkSaYDBeh7X1mlUgExJe5GvT6 YVSAsWYibuWjGsjwtwLOrlg98VBdcT/qzCdDS4wtoOsXn0ZdgCn3WMoxEXSOispOKZwUAgDVZlYv5 UvC14fftxItMVGeY/oyg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1ihJgt-0007AS-CT; Tue, 17 Dec 2019 20:43:35 +0000 Received: from mga11.intel.com ([192.55.52.93]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1ihJeA-0004mj-Oi for linux-arm-kernel@lists.infradead.org; Tue, 17 Dec 2019 20:40:51 +0000 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 17 Dec 2019 12:40:42 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.69,326,1571727600"; d="scan'208";a="389952609" 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 Subject: [PATCH v4 12/19] KVM: Move memslot deletion to helper function Date: Tue, 17 Dec 2019 12:40:34 -0800 Message-Id: <20191217204041.10815-13-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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191217_124046_873343_FEF47EE9 X-CRM114-Status: GOOD ( 19.17 ) X-Spam-Score: -5.0 (-----) X-Spam-Report: SpamAssassin version 3.4.2 on bombadil.infradead.org summary: Content analysis details: (-5.0 points) pts rule name description ---- ---------------------- -------------------------------------------------- -5.0 RCVD_IN_DNSWL_HI RBL: Sender listed at https://www.dnswl.org/, high trust [192.55.52.93 listed in list.dnswl.org] -0.0 RCVD_IN_MSPIKE_H2 RBL: Average reputation (+2) [192.55.52.93 listed in wl.mailspike.net] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arm-kernel@lists.infradead.org, Christoffer Dall , Wanpeng Li , =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= , kvm@vger.kernel.org, David Hildenbrand , Joerg Roedel , Cornelia Huck , linux-mips@vger.kernel.org, Sean Christopherson , linux-kernel@vger.kernel.org, James Morse , kvm-ppc@vger.kernel.org, Vitaly Kuznetsov , Suzuki K Poulose , kvmarm@lists.cs.columbia.edu, Julien Thierry , Jim Mattson Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.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 Signed-off-by: Sean Christopherson --- virt/kvm/kvm_main.c | 73 +++++++++++++++++++++++++++------------------ 1 file changed, 44 insertions(+), 29 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index acf52fa16500..50e5aec0c15c 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1046,6 +1046,27 @@ 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. @@ -1095,7 +1116,15 @@ 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(). + */ + 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; @@ -1103,29 +1132,20 @@ 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)) { @@ -1148,17 +1168,12 @@ 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: