From nobody Fri Dec 19 17:24:20 2025 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=1658308571; cv=none; d=zohomail.com; s=zohoarc; b=MrpIiJ7XN3MQxZTXReWd5U54Xglmgarv44sedOlNiAQAKq62/XXlKTtC7YXyZ6jon+8+EcEKKozYCvEe17746MYY3JNa8AqpzuKx+6ywISK8pzHwb4QuoxGOQ2DbvPg6bioaD0G0ktCRPCtLasqhK2ttKwwGflghahcfFeP2ig4= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1658308571; 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=W2EAtPvsF4CeGJH8vvBNBf6Jt4GMpAr2uSF28zcF3D8=; b=Cee7w+AvDAmSzl9bX2ORASxZUAVg8j/ZJ3pRoNTBEs19rmE7jOhqS7rWlwmNGjFVx88F8tGpdB8eURryjMkPVon6tpOsnhxQOTqxB/8RjB0OsztJihPQgQmKZbTiU1uhbknc+cUTW6xOcyal9GmpL8CHl+9qia+12rjU3yGGZw4= 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 1658308571806201.06628772961085; Wed, 20 Jul 2022 02:16:11 -0700 (PDT) Received: from localhost ([::1]:38042 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oE5oP-0002o6-PT for importer@patchew.org; Wed, 20 Jul 2022 05:16:09 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:58578) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oE5ct-0000Vn-WD for qemu-devel@nongnu.org; Wed, 20 Jul 2022 05:04:16 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:20419) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oE5cr-0001To-4R for qemu-devel@nongnu.org; Wed, 20 Jul 2022 05:04:15 -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-574-3F05olVdN0KJxVtTAllEgA-1; Wed, 20 Jul 2022 05:03:58 -0400 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 9605485A584; Wed, 20 Jul 2022 09:03:58 +0000 (UTC) Received: from localhost.localdomain (ovpn-13-110.pek2.redhat.com [10.72.13.110]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1415A492C3B; Wed, 20 Jul 2022 09:03:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1658307848; 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=W2EAtPvsF4CeGJH8vvBNBf6Jt4GMpAr2uSF28zcF3D8=; b=L2y1WzwdARWoghujC2iD7VIHaD+zKMrcpg1gwD+oV91admGz1B4pgPRPvSNazSBu8CowTe uRbTtXmupFY/+LVwXV36w9xpW1+LuaegL8DoFAZ06S20nffeQlbceQ5hzlFbbP6XGbPT38 3VMOsUhK6fyG2AVaadWBSGoJZzjqWCo= X-MC-Unique: 3F05olVdN0KJxVtTAllEgA-1 From: Jason Wang To: qemu-devel@nongnu.org, peter.maydell@linaro.org Cc: =?UTF-8?q?Eugenio=20P=C3=A9rez?= , "Michael S . Tsirkin" , Jason Wang Subject: [PULL V2 13/25] vhost: add vhost_svq_poll Date: Wed, 20 Jul 2022 17:03:01 +0800 Message-Id: <20220720090313.55169-14-jasowang@redhat.com> In-Reply-To: <20220720090313.55169-1-jasowang@redhat.com> References: <20220720090313.55169-1-jasowang@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.85 on 10.11.54.10 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=170.10.133.124; envelope-from=jasowang@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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" X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1658308573185100003 From: Eugenio P=C3=A9rez It allows the Shadow Control VirtQueue to wait for the device to use the available buffers. Signed-off-by: Eugenio P=C3=A9rez Reviewed-by: Michael S. Tsirkin Signed-off-by: Jason Wang --- hw/virtio/vhost-shadow-virtqueue.c | 27 +++++++++++++++++++++++++++ hw/virtio/vhost-shadow-virtqueue.h | 1 + 2 files changed, 28 insertions(+) diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-vi= rtqueue.c index c3a75ca..cc2ee47 100644 --- a/hw/virtio/vhost-shadow-virtqueue.c +++ b/hw/virtio/vhost-shadow-virtqueue.c @@ -486,6 +486,33 @@ static void vhost_svq_flush(VhostShadowVirtqueue *svq, } =20 /** + * Poll the SVQ for one device used buffer. + * + * This function race with main event loop SVQ polling, so extra + * synchronization is needed. + * + * Return the length written by the device. + */ +size_t vhost_svq_poll(VhostShadowVirtqueue *svq) +{ + int64_t start_us =3D g_get_monotonic_time(); + do { + uint32_t len; + VirtQueueElement *elem =3D vhost_svq_get_buf(svq, &len); + if (elem) { + return len; + } + + if (unlikely(g_get_monotonic_time() - start_us > 10e6)) { + return 0; + } + + /* Make sure we read new used_idx */ + smp_rmb(); + } while (true); +} + +/** * Forward used buffers. * * @n: hdev call event notifier, the one that device set to notify svq. diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-vi= rtqueue.h index dd78f4b..cf442f7 100644 --- a/hw/virtio/vhost-shadow-virtqueue.h +++ b/hw/virtio/vhost-shadow-virtqueue.h @@ -89,6 +89,7 @@ void vhost_svq_push_elem(VhostShadowVirtqueue *svq, int vhost_svq_add(VhostShadowVirtqueue *svq, const struct iovec *out_sg, size_t out_num, const struct iovec *in_sg, size_t in_num, VirtQueueElement *elem); +size_t vhost_svq_poll(VhostShadowVirtqueue *svq); =20 void vhost_svq_set_svq_kick_fd(VhostShadowVirtqueue *svq, int svq_kick_fd); void vhost_svq_set_svq_call_fd(VhostShadowVirtqueue *svq, int call_fd); --=20 2.7.4