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 BA392C4338F for ; Thu, 12 Aug 2021 06:44:33 +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 0561560FE6 for ; Thu, 12 Aug 2021 06:44:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 0561560FE6 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]:40870 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mE4S7-00009u-PS for qemu-devel@archiver.kernel.org; Thu, 12 Aug 2021 02:44:31 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:40944) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mE4RX-0007uI-Bi for qemu-devel@nongnu.org; Thu, 12 Aug 2021 02:43:55 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:44991) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mE4RU-0003QF-1P for qemu-devel@nongnu.org; Thu, 12 Aug 2021 02:43:53 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1628750629; 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=OxK2f2dOVaEVKIiMGORNltMConWOt80seq/4tOJoFCE=; b=RnJ0wk+1YUejJibBc/v0odHWwOGCyJ7OvnO8AqXfn/QIOOzB1LYLyvAMTJ+WpuP7xVu5P1 aNkYg5SL4V7pmdzKNfIVhNm47CyB1fAhBMoKsy9xy2YiTtE8CVJtyj2qg0ZIUoT8S5MolB vEhTxJuiUAcfe/w9V/vC95v6rE4yMlo= Received: from mail-qv1-f72.google.com (mail-qv1-f72.google.com [209.85.219.72]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-167-yqMrAo0jMsS4NzVvfE89Xw-1; Thu, 12 Aug 2021 02:43:48 -0400 X-MC-Unique: yqMrAo0jMsS4NzVvfE89Xw-1 Received: by mail-qv1-f72.google.com with SMTP id w10-20020a0cfc4a0000b0290335dd22451dso2794606qvp.5 for ; Wed, 11 Aug 2021 23:43:48 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=OxK2f2dOVaEVKIiMGORNltMConWOt80seq/4tOJoFCE=; b=C3yUIugxiOuQgyfkCXfmrhPWFKgwrU1Ta5qcquGRzuNUe/7TiWENXeevxM+JD0qDL2 1+SaAlZYTlHyMbiEZCoDFvW/rw9ki4+8mMxoczw2a2MsEHH+tXGNYwHaP79xYw4XZJmG MQihy/dbc2+02g9l/m6JsADvZgEjTpooiRnrcHUg/6dgoaBAzQKp7lR0Aibp5+EcCiHn xm4uhFT3aQJRPChMYhB4jTW3nUiRxp4DjfJXATt8QIik96G0mnwO+AFelR+jgZT0B30G FBU2NooGACbWhNWaIvCdlPMiv53i0WBHRTQ0B1NfyEA3e5xjSSGtl+kQN1xoWbdcQFvQ yDDw== X-Gm-Message-State: AOAM532bnitpmBV4R9wrR0x67pnAUwaCdjitgZqP+VaazTjKt5Xoatec 4agw8aVxXwD9EyuK2DGa0yqqw8UFKh4lAdKTXTfPE8ayuAg3fKW8XtliSSa1TeLybUbQaJQCg1s sCkjKRd7JrYaLvvGz31Kehc9NYKYDS54= X-Received: by 2002:ac8:4e83:: with SMTP id 3mr2457082qtp.221.1628750628149; Wed, 11 Aug 2021 23:43:48 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwObkbJWnDKfmt24xaQ/SFSfIuY/jMOO5MG6Qw9vI6tpEFHy2R7tDVi/V/rzyBmoaVzsrYs1Dx0Ho8w2xeNtyQ= X-Received: by 2002:ac8:4e83:: with SMTP id 3mr2457070qtp.221.1628750627958; Wed, 11 Aug 2021 23:43:47 -0700 (PDT) MIME-Version: 1.0 References: <20210811163211.185870-1-eperezma@redhat.com> In-Reply-To: From: Eugenio Perez Martin Date: Thu, 12 Aug 2021 08:43:12 +0200 Message-ID: Subject: Re: [PATCH v2] vhost-vdpa: Do not send empty IOTLB update batches To: Jason Wang 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: quoted-printable 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=-0.7, 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 , qemu-devel , Cindy Lu , "Michael S. Tsirkin" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, Aug 12, 2021 at 8:16 AM Jason Wang wrote: > > On Thu, Aug 12, 2021 at 12:32 AM Eugenio P=C3=A9rez = wrote: > > > > 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. > > > > Signed-off-by: Eugenio P=C3=A9rez > > --- > > include/hw/virtio/vhost-vdpa.h | 1 + > > hw/virtio/vhost-vdpa.c | 50 ++++++++++++++++++++++++++-------- > > 2 files changed, 39 insertions(+), 12 deletions(-) > > > > diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-v= dpa.h > > index e98e327f12..6538572a6f 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_mr_updated; > > 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..512fa18d68 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 =3D container_of(listener, struct vhost_vdpa,= listener); > > - struct vhost_dev *dev =3D v->dev; > > - struct vhost_msg_v2 msg =3D {}; > > int fd =3D v->device_fd; > > - > > - if (!(dev->backend_cap & (0x1ULL << VHOST_BACKEND_F_IOTLB_BATCH)))= { > > - return; > > - } > > - > > - msg.type =3D v->msg_type; > > - msg.iotlb.type =3D VHOST_IOTLB_BATCH_BEGIN; > > + struct vhost_msg_v2 msg =3D { > > + .type =3D v->msg_type, > > + .iotlb.type =3D VHOST_IOTLB_BATCH_BEGIN, > > + }; > > > > if (write(fd, &msg, sizeof(msg)) !=3D sizeof(msg)) { > > error_report("failed to write, fd=3D%d, errno=3D%d (%s)", > > @@ -109,6 +103,25 @@ static void vhost_vdpa_listener_begin(MemoryListen= er *listener) > > } > > } > > > > +static bool vhost_vdpa_iotlb_batch_is_started(const struct vhost_vdpa = *v) > > +{ > > + return v->n_mr_updated !=3D 0; > > +} > > + > > +static void vhost_vdpa_iotlb_batch_begin_once(struct vhost_vdpa *v) > > +{ > > + if (!vhost_vdpa_iotlb_batch_is_started(v)) { > > + vhost_vdpa_listener_begin_batch(v); > > + } > > + > > + v->n_mr_updated++; > > +} > > + > > +static void vhost_vdpa_iotlb_batch_reset(struct vhost_vdpa *v) > > +{ > > + v->n_mr_updated =3D 0; > > +} > > + > > static void vhost_vdpa_listener_commit(MemoryListener *listener) > > { > > struct vhost_vdpa *v =3D container_of(listener, struct vhost_vdpa,= listener); > > @@ -120,6 +133,10 @@ static void vhost_vdpa_listener_commit(MemoryListe= ner *listener) > > return; > > } > > > > + if (vhost_vdpa_iotlb_batch_is_started(v)) { > > + return; > > + } > > + > > msg.type =3D v->msg_type; > > msg.iotlb.type =3D VHOST_IOTLB_BATCH_END; > > > > @@ -127,6 +144,8 @@ static void vhost_vdpa_listener_commit(MemoryListen= er *listener) > > error_report("failed to write, fd=3D%d, errno=3D%d (%s)", > > fd, errno, strerror(errno)); > > } > > + > > + vhost_vdpa_iotlb_batch_reset(v); > > } > > > > static void vhost_vdpa_listener_region_add(MemoryListener *listener, > > @@ -170,6 +189,10 @@ static void vhost_vdpa_listener_region_add(MemoryL= istener *listener, > > > > llsize =3D int128_sub(llend, int128_make64(iova)); > > > > + if (v->dev->backend_cap & (0x1ULL << VHOST_BACKEND_F_IOTLB_BATCH))= { > > Let's move this in to vhost_vdpa_iotlb_batch_begin_once()? > Sure > > + vhost_vdpa_iotlb_batch_begin_once(v); > > + } > > + > > ret =3D vhost_vdpa_dma_map(v, iova, int128_get64(llsize), > > vaddr, section->readonly); > > if (ret) { > > @@ -221,6 +244,10 @@ static void vhost_vdpa_listener_region_del(MemoryL= istener *listener, > > > > llsize =3D int128_sub(llend, int128_make64(iova)); > > > > + if (v->dev->backend_cap & (0x1ULL << VHOST_BACKEND_F_IOTLB_BATCH))= { > > + vhost_vdpa_iotlb_batch_begin_once(v); > > + } > > + > > Do we need to check vhost_vdpa_iotlb_batch_is_started() in the .commit? > I don't follow you here. It's that comment in this position of the patch for a reason? That checking is the one that allows qemu to skip the IOTLB_END write. > Others look good. > > Thanks > > > ret =3D vhost_vdpa_dma_unmap(v, iova, int128_get64(llsize)); > > if (ret) { > > error_report("vhost_vdpa dma unmap error!"); > > @@ -234,7 +261,6 @@ static void vhost_vdpa_listener_region_del(MemoryLi= stener *listener, > > * depends on the addnop(). > > */ > > static const MemoryListener vhost_vdpa_memory_listener =3D { > > - .begin =3D vhost_vdpa_listener_begin, > > .commit =3D vhost_vdpa_listener_commit, > > .region_add =3D vhost_vdpa_listener_region_add, > > .region_del =3D vhost_vdpa_listener_region_del, > > -- > > 2.27.0 > > >