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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 23B36C4338F for ; Wed, 4 Aug 2021 15:25:59 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 86D5C60C3F for ; Wed, 4 Aug 2021 15:25:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 86D5C60C3F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:34798 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mBImL-0003Fp-Ew for qemu-devel@archiver.kernel.org; Wed, 04 Aug 2021 11:25:57 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:35716) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mBI86-0007t6-6x for qemu-devel@nongnu.org; Wed, 04 Aug 2021 10:44:22 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:34581) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mBI84-00063P-Mr for qemu-devel@nongnu.org; Wed, 04 Aug 2021 10:44:21 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1628088259; 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; bh=gH0VFgCRqk1qi7U3LKL3479tXvUotLhlTiFjwmmnQkI=; b=eU37kfacTPaO53MAQLw1tLPy7qKdcWA/JzIyeCYt6Ad4P93trMnj4MmRn5Z8IDB6onF1xQ 6oG75Wg2vsFU96anSqYgrR9fZGkTDdiufnRuifnJy+q4CFet1ew9RqgPuWRLPp/rmLAm3J 0glVZD23PynqhHc9ZFgzEzJRaqnivoc= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-394-F77lNHb7Py-XWYHx4CSumQ-1; Wed, 04 Aug 2021 10:44:16 -0400 X-MC-Unique: F77lNHb7Py-XWYHx4CSumQ-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9216A801AEB; Wed, 4 Aug 2021 14:44:15 +0000 (UTC) Received: from eperezma.remote.csb (unknown [10.39.192.171]) by smtp.corp.redhat.com (Postfix) with ESMTP id 12D473AA2; Wed, 4 Aug 2021 14:44:09 +0000 (UTC) From: =?UTF-8?q?Eugenio=20P=C3=A9rez?= To: qemu-devel@nongnu.org Subject: [RFC PATCH] vhost-vdpa: Do not send empty IOTLB update batches Date: Wed, 4 Aug 2021 16:44:02 +0200 Message-Id: <20210804144402.711594-1-eperezma@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eperezma@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=eperezma@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.699, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jason Wang , Eli Cohen , Cindy Lu , "Michael S. Tsirkin" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" With the introduction of the batch hinting, meaningless batches can be created with no IOTLB updates if the memory region was skipped by vhost_vdpa_listener_skipped_section. This is the case of host notifiers memory regions, but others could fall on this category. This caused the vdpa device to receive dma mapping settings with no changes, a possibly expensive operation for nothing. To avoid that, VHOST_IOTLB_BATCH_BEGIN hint is delayed until we have a meaningful (not skipped section) mapping or unmapping operation, and VHOST_IOTLB_BATCH_END is not written unless at least one of _UPDATE / _INVALIDATE has been issued. Signed-off-by: Eugenio Pérez --- include/hw/virtio/vhost-vdpa.h | 1 + hw/virtio/vhost-vdpa.c | 38 +++++++++++++++++++++++----------- 2 files changed, 27 insertions(+), 12 deletions(-) diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h index e98e327f12..0a7edbe4eb 100644 --- a/include/hw/virtio/vhost-vdpa.h +++ b/include/hw/virtio/vhost-vdpa.h @@ -23,6 +23,7 @@ typedef struct vhost_vdpa { int device_fd; int index; uint32_t msg_type; + size_t n_iotlb_sent_batch; MemoryListener listener; struct vhost_dev *dev; VhostVDPAHostNotifier notifier[VIRTIO_QUEUE_MAX]; diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c index 6ce94a1f4d..2517fc6103 100644 --- a/hw/virtio/vhost-vdpa.c +++ b/hw/virtio/vhost-vdpa.c @@ -89,19 +89,13 @@ static int vhost_vdpa_dma_unmap(struct vhost_vdpa *v, hwaddr iova, return ret; } -static void vhost_vdpa_listener_begin(MemoryListener *listener) +static void vhost_vdpa_listener_begin_batch(struct vhost_vdpa *v) { - struct vhost_vdpa *v = container_of(listener, struct vhost_vdpa, listener); - struct vhost_dev *dev = v->dev; - struct vhost_msg_v2 msg = {}; int fd = v->device_fd; - - if (!(dev->backend_cap & (0x1ULL << VHOST_BACKEND_F_IOTLB_BATCH))) { - return; - } - - msg.type = v->msg_type; - msg.iotlb.type = VHOST_IOTLB_BATCH_BEGIN; + struct vhost_msg_v2 msg = { + .type = v->msg_type, + .iotlb.type = VHOST_IOTLB_BATCH_BEGIN, + }; if (write(fd, &msg, sizeof(msg)) != sizeof(msg)) { error_report("failed to write, fd=%d, errno=%d (%s)", @@ -120,6 +114,11 @@ static void vhost_vdpa_listener_commit(MemoryListener *listener) return; } + if (v->n_iotlb_sent_batch == 0) { + return; + } + + v->n_iotlb_sent_batch = 0; msg.type = v->msg_type; msg.iotlb.type = VHOST_IOTLB_BATCH_END; @@ -170,6 +169,14 @@ static void vhost_vdpa_listener_region_add(MemoryListener *listener, llsize = int128_sub(llend, int128_make64(iova)); + if (v->dev->backend_cap & (0x1ULL << VHOST_BACKEND_F_IOTLB_BATCH)) { + if (v->n_iotlb_sent_batch == 0) { + vhost_vdpa_listener_begin_batch(v); + } + + v->n_iotlb_sent_batch++; + } + ret = vhost_vdpa_dma_map(v, iova, int128_get64(llsize), vaddr, section->readonly); if (ret) { @@ -221,6 +228,14 @@ static void vhost_vdpa_listener_region_del(MemoryListener *listener, llsize = int128_sub(llend, int128_make64(iova)); + if (v->dev->backend_cap & (0x1ULL << VHOST_BACKEND_F_IOTLB_BATCH)) { + if (v->n_iotlb_sent_batch == 0) { + vhost_vdpa_listener_begin_batch(v); + } + + v->n_iotlb_sent_batch++; + } + ret = vhost_vdpa_dma_unmap(v, iova, int128_get64(llsize)); if (ret) { error_report("vhost_vdpa dma unmap error!"); @@ -234,7 +249,6 @@ static void vhost_vdpa_listener_region_del(MemoryListener *listener, * depends on the addnop(). */ static const MemoryListener vhost_vdpa_memory_listener = { - .begin = vhost_vdpa_listener_begin, .commit = vhost_vdpa_listener_commit, .region_add = vhost_vdpa_listener_region_add, .region_del = vhost_vdpa_listener_region_del, -- 2.27.0