From nobody Sat Feb 7 07:11:16 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1695754887; cv=none; d=zohomail.com; s=zohoarc; b=mTtPbh/MS6Z2g6aSK5DbdjTUSAPEJnyP0WEJg59y+kq/7Bd4y0ctr1PWkqcFpN/APWeYoaaduBNSygyIvFuRpBbt917KEgEUPXhbPZDLsw0T6mJCTMJOUWehgYj+G1E3qHK8l8v0Ts1P4qbhVBA/SDqZDY9/kaOPh4FoehO2ZF8= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1695754887; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=jAvglJj91/o8R3ulPUvMP06jx5ezTDNURc+rL2BIGo4=; b=DecIIl+FIP2D7emgm7NgYp7QeacvqA7KShleCZanYWEpsXJHaLBoleQOaIJFlWJ1zZNmmfI/i0fOwJxsgBNUp7/ghi7ELG00UwwqPvvWMzOd8jIORvgbU/B/z6F88qF0YVmM5EQM/GzRXxY89O1rmYBpLUwWdjAr7vy+A4hQ9Ok= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=none dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1695754887485968.2991461329835; Tue, 26 Sep 2023 12:01:27 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qlDIJ-0002M2-UY; Tue, 26 Sep 2023 15:00:28 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qlDI8-0001to-8e for qemu-devel@nongnu.org; Tue, 26 Sep 2023 15:00:16 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qlDI4-0003Uq-Ix for qemu-devel@nongnu.org; Tue, 26 Sep 2023 15:00:15 -0400 Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-281-t_nnSmVvNL-nvOoa5tOcxg-1; Tue, 26 Sep 2023 15:00:07 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 1DE3E811E8E; Tue, 26 Sep 2023 19:00:07 +0000 (UTC) Received: from t14s.fritz.box (unknown [10.39.192.33]) by smtp.corp.redhat.com (Postfix) with ESMTP id B9B372026D4B; Tue, 26 Sep 2023 19:00:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1695754811; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=jAvglJj91/o8R3ulPUvMP06jx5ezTDNURc+rL2BIGo4=; b=hR12PzKXXvgb//rP8/f7FQccH0FZyKQbaawQnhzy2V+TVcxtJRRVw2KKXx+SYqNZOyT8Ro 5EE4TTfACEKDkiFVFP0UbCGnrIPUetn+m6flyA9GOQMdfJ+qEczZxyWzHo4ju6C7Z+Qs/v KcrmJg5mJ+eLK0qbyMEAxfuXirZxXhg= X-MC-Unique: t_nnSmVvNL-nvOoa5tOcxg-1 From: David Hildenbrand To: qemu-devel@nongnu.org Cc: David Hildenbrand , Paolo Bonzini , Igor Mammedov , Xiao Guangrong , "Michael S. Tsirkin" , Peter Xu , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Eduardo Habkost , Marcel Apfelbaum , Yanan Wang , Michal Privoznik , =?UTF-8?q?Daniel=20P=20=2E=20Berrang=C3=A9?= , Gavin Shan , Alex Williamson , Stefan Hajnoczi , "Maciej S . Szmigiero" , kvm@vger.kernel.org Subject: [PATCH v4 18/18] virtio-mem: Mark memslot alias memory regions unmergeable Date: Tue, 26 Sep 2023 20:57:38 +0200 Message-ID: <20230926185738.277351-19-david@redhat.com> In-Reply-To: <20230926185738.277351-1-david@redhat.com> References: <20230926185738.277351-1-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.4 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.129.124; envelope-from=david@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1695754888836100003 Let's mark the memslot alias memory regions as unmergable, such that flatview and vhost won't merge adjacent memory region aliases and we can atomically map/unmap individual aliases without affecting adjacent alias memory regions. This handles vhost and vfio in multiple-memslot mode correctly (which do not support atomic memslot updates) and avoids the temporary removal of large memslots, which can be an expensive operation. For example, vfio might have to unpin + repin a lot of memory, which is undesired. Reviewed-by: Philippe Mathieu-Daud=C3=A9 Signed-off-by: David Hildenbrand --- hw/virtio/virtio-mem.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c index e1e4250e69..9dc3c61b5a 100644 --- a/hw/virtio/virtio-mem.c +++ b/hw/virtio/virtio-mem.c @@ -940,6 +940,12 @@ static void virtio_mem_prepare_memslots(VirtIOMEM *vme= m) memory_region_init_alias(&vmem->memslots[idx], OBJECT(vmem), name, &vmem->memdev->mr, memslot_offset, memslot_size); + /* + * We want to be able to atomically and efficiently activate/deact= ivate + * individual memslots without affecting adjacent memslots in memo= ry + * notifiers. + */ + memory_region_set_unmergeable(&vmem->memslots[idx], true); } } =20 --=20 2.41.0