From nobody Mon Feb 9 10:29:07 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=1658301098; cv=none; d=zohomail.com; s=zohoarc; b=HdwZN3xaTssA1tiFw98SxyqueYH7XlGDeFNjbJFKNiK66faXNMHKbpA9yWKbWfRDjhssUXWtQ2NbEu3fbgHwlXbex33kGP4WRjm+hDfSVBUx/i/gk0w6rDoFBuWFv2uT6uuQU7mS+BNfc/apzozp/3C3QUuReQoOcV9QIDtr3vo= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1658301098; 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=Xoe+cGkzHLFJpmtbzvDHZeGstk1xLlSNkdsoFgaaOos=; b=P/V8EB4ZMyoBkllZ/RHJc/vW50qSzFCEVNGFefOf3JL3En7n/UObjAkYgnGzhloTSyiWq0iiXi3UbQ0Qhw8RnAcBUm5v0sl054dHskKcRO+thJN5pcahM381N2bi31oAdwoCd/Go/LuZBWMSa14ZbgxZc5q1TvcjJrVwjc07uFg= 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 1658301098604243.494153810179; Wed, 20 Jul 2022 00:11:38 -0700 (PDT) Received: from localhost ([::1]:53580 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oE3rq-0003TK-V6 for importer@patchew.org; Wed, 20 Jul 2022 03:11:36 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:33734) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oE3hY-0000Zc-Su for qemu-devel@nongnu.org; Wed, 20 Jul 2022 03:00:58 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:25482) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oE3hU-0006fg-TF for qemu-devel@nongnu.org; Wed, 20 Jul 2022 03:00:55 -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-9-57ZgvEE7NcO3XBeQWLi3zQ-1; Wed, 20 Jul 2022 03:00:37 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id C0488185A794; Wed, 20 Jul 2022 07:00:36 +0000 (UTC) Received: from eperezma.remote.csb (unknown [10.39.192.102]) by smtp.corp.redhat.com (Postfix) with ESMTP id A9B9618ECC; Wed, 20 Jul 2022 07:00:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1658300451; 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=Xoe+cGkzHLFJpmtbzvDHZeGstk1xLlSNkdsoFgaaOos=; b=I1putyzmOLgdFyKYUmJEO6+ko+GQkpXoKc36FaRkadtrb09zU3q6w1sy6ao20jhHbvdggh JH68MPg0mKTFer7zrSepm+KpCn6EYaMuO0nHBag1Nxuhw1DbFRgbM2vvfrNggCkLODT5zk xXLXdNYbht1mEGoIrhwDz27kWrXicl4= X-MC-Unique: 57ZgvEE7NcO3XBeQWLi3zQ-1 From: =?UTF-8?q?Eugenio=20P=C3=A9rez?= To: qemu-devel@nongnu.org Cc: Stefano Garzarella , Liuxiangdong , Cornelia Huck , Laurent Vivier , Eli Cohen , Harpreet Singh Anand , Cindy Lu , Eric Blake , Zhu Lingshan , Jason Wang , Gautam Dawar , Parav Pandit , "Michael S. Tsirkin" , Markus Armbruster , Stefan Hajnoczi , Paolo Bonzini , "Gonglei (Arei)" Subject: [PATCH v6 13/21] vhost: add vhost_svq_poll Date: Wed, 20 Jul 2022 08:59:38 +0200 Message-Id: <20220720065946.3122611-14-eperezma@redhat.com> In-Reply-To: <20220720065946.3122611-1-eperezma@redhat.com> References: <20220720065946.3122611-1-eperezma@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 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=eperezma@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 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_LOW=-0.7, 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: 1658301099255100001 It allows the Shadow Control VirtQueue to wait for the device to use the available buffers. Signed-off-by: Eugenio P=C3=A9rez --- hw/virtio/vhost-shadow-virtqueue.h | 1 + hw/virtio/vhost-shadow-virtqueue.c | 27 +++++++++++++++++++++++++++ 2 files changed, 28 insertions(+) diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-vi= rtqueue.h index dd78f4bec2..cf442f7dea 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); diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-vi= rtqueue.c index c3a75ca89e..cc2ee4780d 100644 --- a/hw/virtio/vhost-shadow-virtqueue.c +++ b/hw/virtio/vhost-shadow-virtqueue.c @@ -485,6 +485,33 @@ static void vhost_svq_flush(VhostShadowVirtqueue *svq, } while (!vhost_svq_enable_notification(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. * --=20 2.31.1