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 D2F84C4338F for ; Thu, 12 Aug 2021 14:10:38 +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 220BB6104F for ; Thu, 12 Aug 2021 14:10:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 220BB6104F 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]:50212 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mEBPo-0008DA-Sb for qemu-devel@archiver.kernel.org; Thu, 12 Aug 2021 10:10:36 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48418) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mEBPA-0007Yt-Ip for qemu-devel@nongnu.org; Thu, 12 Aug 2021 10:09:56 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:44043) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mEBP7-0005ZV-5z for qemu-devel@nongnu.org; Thu, 12 Aug 2021 10:09:55 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1628777391; 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=UW+OQJtrA24PptZq9wMviUodh52mL0/1urrh9rqF2FQ=; b=DNWdpHsIJFwjotS003yU82cGYUor83uLQsyqrX+0j/3P3hRafbduBYrp57U+fzlfnS43dC Cr9ilRgVhpqtJSO3+bH+LVITsEhFeGsce2s8bTi95X2qKfJACHJPpqe8hS0magnG5VmpS6 hieBSeUvZ5hJG4Wb/U0A717tvo+dhWU= 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-399-Gt51cXfLMNOHMK__g7ujeA-1; Thu, 12 Aug 2021 10:09:48 -0400 X-MC-Unique: Gt51cXfLMNOHMK__g7ujeA-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0ED98190A7C1; Thu, 12 Aug 2021 14:09:47 +0000 (UTC) Received: from eperezma.remote.csb (unknown [10.39.194.30]) by smtp.corp.redhat.com (Postfix) with ESMTP id 12E6960C04; Thu, 12 Aug 2021 14:09:40 +0000 (UTC) From: =?UTF-8?q?Eugenio=20P=C3=A9rez?= To: qemu-devel@nongnu.org Subject: [PATCH v3] vhost-vdpa: Do not send empty IOTLB update batches Date: Thu, 12 Aug 2021 16:09:33 +0200 Message-Id: <20210812140933.226288-1-eperezma@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 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=216.205.24.124; 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=-0.701, 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: Eli Cohen , Jason Wang , 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, device un/realize, and others. This causes 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. v3: * Use a bool instead of a counter avoiding potential number wrapping * Fix bad check on _commit * Move VHOST_BACKEND_F_IOTLB_BATCH check to vhost_vdpa_iotlb_batch_begin_once v2 (from RFC): * Rename misleading name * Abstract start batching function for listener_add/del Signed-off-by: Eugenio Pérez --- include/hw/virtio/vhost-vdpa.h | 1 + hw/virtio/vhost-vdpa.c | 35 ++++++++++++++++++++++------------ 2 files changed, 24 insertions(+), 12 deletions(-) diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h index e98e327f12..6b9288fef8 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; + bool iotlb_batch_begin_sent; 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..93b7db61d1 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)", @@ -109,6 +103,16 @@ static void vhost_vdpa_listener_begin(MemoryListener *listener) } } +static void vhost_vdpa_iotlb_batch_begin_once(struct vhost_vdpa *v) +{ + if (v->dev->backend_cap & (0x1ULL << VHOST_BACKEND_F_IOTLB_BATCH) && + !v->iotlb_batch_begin_sent) { + vhost_vdpa_listener_begin_batch(v); + } + + v->iotlb_batch_begin_sent = true; +} + static void vhost_vdpa_listener_commit(MemoryListener *listener) { struct vhost_vdpa *v = container_of(listener, struct vhost_vdpa, listener); @@ -120,6 +124,10 @@ static void vhost_vdpa_listener_commit(MemoryListener *listener) return; } + if (!v->iotlb_batch_begin_sent) { + return; + } + msg.type = v->msg_type; msg.iotlb.type = VHOST_IOTLB_BATCH_END; @@ -127,6 +135,8 @@ static void vhost_vdpa_listener_commit(MemoryListener *listener) error_report("failed to write, fd=%d, errno=%d (%s)", fd, errno, strerror(errno)); } + + v->iotlb_batch_begin_sent = false; } static void vhost_vdpa_listener_region_add(MemoryListener *listener, @@ -170,6 +180,7 @@ static void vhost_vdpa_listener_region_add(MemoryListener *listener, llsize = int128_sub(llend, int128_make64(iova)); + vhost_vdpa_iotlb_batch_begin_once(v); ret = vhost_vdpa_dma_map(v, iova, int128_get64(llsize), vaddr, section->readonly); if (ret) { @@ -221,6 +232,7 @@ static void vhost_vdpa_listener_region_del(MemoryListener *listener, llsize = int128_sub(llend, int128_make64(iova)); + vhost_vdpa_iotlb_batch_begin_once(v); ret = vhost_vdpa_dma_unmap(v, iova, int128_get64(llsize)); if (ret) { error_report("vhost_vdpa dma unmap error!"); @@ -234,7 +246,6 @@ 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