From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EE54DC47E49 for ; Wed, 23 Oct 2019 09:30:23 +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 C29DB222C2 for ; Wed, 23 Oct 2019 09:30:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="nYrLsQgT" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C29DB222C2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.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:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=IExLBJ76keXxy97WZkptfSxHB0d4GlOP4QH5Pxk/+eM=; b=nYrLsQgTJQR/ni IRBCMBH9iRs3IKvufkyVAaiSOahnglgnWcjw1zMcLJZUvE5SXeZMhQsmPoscDRTSYH2eZ6SUF8X+J Cw+jR1yEria3b29Hnq75LSeScM1a7lZugY5V+yaGunY3rTgayxgBkO0zcGXduHazcwhDuVoObady/ 1cXuFBTJIk+3PK0vEyyUNI2mZ2LBxxjRij3LQL8ilzpwulao/sXrv64AB7ce09PcdVf7B3i1kYcqS pxo3oroFnBYW70lgasNoF3tseVZ6gRHlzuIWv922l8mD0z/Lc0xJAqDyxjRcy6YW5dORvuLZEsYaZ zLs73Al2am6pLARgsy2Q==; 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 1iNCyE-0001N7-MG; Wed, 23 Oct 2019 09:30:22 +0000 Received: from [217.140.110.172] (helo=foss.arm.com) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1iNCxH-0007u0-D8 for linux-arm-kernel@lists.infradead.org; Wed, 23 Oct 2019 09:29:24 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 92F5932B; Wed, 23 Oct 2019 02:29:09 -0700 (PDT) Received: from localhost (e113682-lin.copenhagen.arm.com [10.32.145.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1CDE23F718; Wed, 23 Oct 2019 02:29:08 -0700 (PDT) Date: Wed, 23 Oct 2019 11:29:07 +0200 From: Christoffer Dall To: Sean Christopherson Subject: Re: [PATCH v2 01/15] KVM: Reinstall old memslots if arch preparation fails Message-ID: <20191023092907.GD2652@e113682-lin.lund.arm.com> References: <20191022003537.13013-1-sean.j.christopherson@intel.com> <20191022003537.13013-2-sean.j.christopherson@intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20191022003537.13013-2-sean.j.christopherson@intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191023_022923_535027_288D879C X-CRM114-Status: GOOD ( 20.04 ) 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: Cornelia Huck , Wanpeng Li , Janosch Frank , kvm@vger.kernel.org, Radim =?utf-8?B?S3LEjW3DocWZ?= , James Hogan , Joerg Roedel , David Hildenbrand , linux-mips@vger.kernel.org, kvm-ppc@vger.kernel.org, linux-kernel@vger.kernel.org, Paul Mackerras , Christian Borntraeger , Marc Zyngier , Paolo Bonzini , Vitaly Kuznetsov , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, Jim Mattson Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Oct 21, 2019 at 05:35:23PM -0700, Sean Christopherson wrote: > Reinstall the old memslots if preparing the new memory region fails > after invalidating a to-be-{re}moved memslot. > > Remove the superfluous 'old_memslots' variable so that it's somewhat > clear that the error handling path needs to free the unused memslots, > not simply the 'old' memslots. > > Fixes: bc6678a33d9b9 ("KVM: introduce kvm->srcu and convert kvm_set_memory_region to SRCU update") > Signed-off-by: Sean Christopherson > --- > virt/kvm/kvm_main.c | 23 ++++++++++++----------- > 1 file changed, 12 insertions(+), 11 deletions(-) > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index 67ef3f2e19e8..9afd706dc038 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -924,7 +924,7 @@ int __kvm_set_memory_region(struct kvm *kvm, > unsigned long npages; > struct kvm_memory_slot *slot; > struct kvm_memory_slot old, new; > - struct kvm_memslots *slots = NULL, *old_memslots; > + struct kvm_memslots *slots; > int as_id, id; > enum kvm_mr_change change; > > @@ -1032,7 +1032,13 @@ int __kvm_set_memory_region(struct kvm *kvm, > slot = id_to_memslot(slots, id); > slot->flags |= KVM_MEMSLOT_INVALID; > > - old_memslots = install_new_memslots(kvm, as_id, slots); > + /* > + * We can re-use the old memslots, the only difference from the > + * newly installed memslots is the invalid flag, which will get > + * dropped by update_memslots anyway. We'll also revert to the > + * old memslots if preparing the new memory region fails. > + */ > + slots = install_new_memslots(kvm, as_id, slots); > > /* From this point no new shadow pages pointing to a deleted, > * or moved, memslot will be created. > @@ -1042,13 +1048,6 @@ int __kvm_set_memory_region(struct kvm *kvm, > * - kvm_is_visible_gfn (mmu_check_roots) > */ > kvm_arch_flush_shadow_memslot(kvm, slot); > - > - /* > - * We can re-use the old_memslots from above, the only difference > - * from the currently installed memslots is the invalid flag. This > - * will get overwritten by update_memslots anyway. > - */ > - slots = old_memslots; > } > > r = kvm_arch_prepare_memory_region(kvm, &new, mem, change); > @@ -1062,15 +1061,17 @@ int __kvm_set_memory_region(struct kvm *kvm, > } > > update_memslots(slots, &new, change); > - old_memslots = install_new_memslots(kvm, as_id, slots); > + slots = install_new_memslots(kvm, as_id, slots); > > kvm_arch_commit_memory_region(kvm, mem, &old, &new, change); > > kvm_free_memslot(kvm, &old, &new); > - kvfree(old_memslots); > + kvfree(slots); > return 0; > > out_slots: > + if (change == KVM_MR_DELETE || change == KVM_MR_MOVE) > + slots = install_new_memslots(kvm, as_id, slots); > kvfree(slots); > out_free: > kvm_free_memslot(kvm, &new, &old); > -- > 2.22.0 Reviewed-by: Christoffer Dall _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel