From patchwork Thu Oct 24 23:07:38 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 11211141 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 89A69139A for ; Thu, 24 Oct 2019 23:10:54 +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 5184B21A4C for ; Thu, 24 Oct 2019 23:10:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="YVJKhlH9" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5184B21A4C 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=QAcmn/dmnYoVI5c/jCsJyPBEYcXL6h+/Kc+vYxFKO8g=; b=YVJKhlH9RUNwj9 yZlwTQRv2X9gwjRDrbHX8L+HOQIi+1m59S3JVB7eiMBDx6PT6bHXsafpKMNu0zrPUR/TRWJ4F4WlV Rgl6RzVt/IrRJNsF+9vB8UZQM8fLHDIBBLvAwPCOqCVSc4cg+mBZZbfTm8n+KSfnEXF7Dq7aJAyX7 gM2jGNCJnujr6qxlOWYG4YB910ehPntBiltuakGlv/VP0OSryNro42O2XWttI9mNkl7ykBcJHGZV8 hIb+YUFIbR4dx2rQsCe3MByXuR1bMAEijO2IgxDuEWiVRT7JADdegPvjM/Sp+cOw45YrBU87HOrew BVMtqmSu8RfCYfyJ8Lyg==; 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 1iNmFm-0007PE-T0; Thu, 24 Oct 2019 23:10:50 +0000 Received: from mga02.intel.com ([134.134.136.20]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1iNmD0-0003iY-FG for linux-arm-kernel@lists.infradead.org; Thu, 24 Oct 2019 23:08:00 +0000 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 24 Oct 2019 16:07:46 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.68,226,1569308400"; d="scan'208";a="202445857" Received: from sjchrist-coffee.jf.intel.com ([10.54.74.41]) by orsmga006.jf.intel.com with ESMTP; 24 Oct 2019 16:07:46 -0700 From: Sean Christopherson To: James Hogan , Paul Mackerras , Christian Borntraeger , Janosch Frank , Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= , Marc Zyngier Subject: [PATCH v3 09/15] KVM: Move memslot deletion to helper function Date: Thu, 24 Oct 2019 16:07:38 -0700 Message-Id: <20191024230744.14543-10-sean.j.christopherson@intel.com> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20191024230744.14543-1-sean.j.christopherson@intel.com> References: <20191024230744.14543-1-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-20191024_160758_586846_ECE448BE X-CRM114-Status: GOOD ( 19.72 ) X-Spam-Score: -2.3 (--) X-Spam-Report: SpamAssassin version 3.4.2 on bombadil.infradead.org summary: Content analysis details: (-2.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at https://www.dnswl.org/, medium trust [134.134.136.20 listed in list.dnswl.org] -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 , 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, i.e. implement logic similar to the dirty bitmap handling, if such functionality is needed in the future. 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 860de4fadce6..2163a7157c63 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -980,6 +980,27 @@ 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. @@ -1029,7 +1050,15 @@ 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; @@ -1037,29 +1066,20 @@ 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)) { @@ -1082,17 +1102,12 @@ 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: