From nobody Mon Feb 9 08:10:07 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=1657906914; cv=none; d=zohomail.com; s=zohoarc; b=jhcos0KjsSw8N+2b/FNJkdqK6KE3SGl4MkxomNUuufvPUvkcjvP+WeB22kKqzuoNml4IG3XE5L/ARSvp3q7nlwdnKqa27Iaiy8UOwWCG5xfUv7EqY2OvuY+TyaxoMs/kHx1WtF+ju/zlJySeCz8qli4yRQ7H9omVvGK60ZXf51A= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1657906914; 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=E6kNbFYJPMUsUjgamMxmHDhPTmIfs8l+nCthBXwFY2I=; b=jnm+VJKhDRguCPKw0AnODxAN6pIv66S+dBkAXttap3avLZXtrrFD3LL63xbaRbAGShvWTrDFG1pUayoFB/WUwd6DXrmW1f8annDX7ziCbodNiFl7MgPp5WcQacKSnZF2WJPvblXdh4fuWhT//EBvX3cFR+362J/n9ll8paDvlI4= 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 1657906914988167.2886653804079; Fri, 15 Jul 2022 10:41:54 -0700 (PDT) Received: from localhost ([::1]:39374 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oCPK5-0000Fe-6l for importer@patchew.org; Fri, 15 Jul 2022 13:41:53 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:46366) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oCOyS-0005wY-CL for qemu-devel@nongnu.org; Fri, 15 Jul 2022 13:19:33 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:34059) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oCOyQ-0005vo-Tr for qemu-devel@nongnu.org; Fri, 15 Jul 2022 13:19:32 -0400 Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-482-a5lpfLi0OaGIY7Ad4i2HLw-1; Fri, 15 Jul 2022 13:19:18 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 4339F1C05154; Fri, 15 Jul 2022 17:19:18 +0000 (UTC) Received: from eperezma.remote.csb (unknown [10.39.192.71]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5894540E8B04; Fri, 15 Jul 2022 17:19:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1657905568; 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=E6kNbFYJPMUsUjgamMxmHDhPTmIfs8l+nCthBXwFY2I=; b=EAQA1Ar+btrPZU8CPOOxg2dkYYfjx3L+CIvifUBBvm25573PIqGZErJADl9TOTpAq39gmk J692iwhDK3OmOKn5fMaKS6M6Sg+WaMBlx7cfWeHKZC5gXNCpxrtJ77zhHR9l1uW282KPF7 4wCQ4DkLbhrN0c59N79K5s+CcCIfL4Y= X-MC-Unique: a5lpfLi0OaGIY7Ad4i2HLw-1 From: =?UTF-8?q?Eugenio=20P=C3=A9rez?= To: qemu-devel@nongnu.org Cc: Cornelia Huck , "Gonglei (Arei)" , Stefano Garzarella , Eli Cohen , "Michael S. Tsirkin" , Jason Wang , Stefan Hajnoczi , Cindy Lu , Zhu Lingshan , Parav Pandit , Markus Armbruster , Liuxiangdong , Laurent Vivier , Gautam Dawar , Eric Blake , Harpreet Singh Anand , Paolo Bonzini Subject: [PATCH v3 12/19] vhost: add vhost_svq_poll Date: Fri, 15 Jul 2022 19:18:27 +0200 Message-Id: <20220715171834.2666455-13-eperezma@redhat.com> In-Reply-To: <20220715171834.2666455-1-eperezma@redhat.com> References: <20220715171834.2666455-1-eperezma@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.84 on 10.11.54.2 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=eperezma@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: 1657906915950100001 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 | 22 ++++++++++++++++++++++ 2 files changed, 23 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 406a823c81..1c54a03e17 100644 --- a/hw/virtio/vhost-shadow-virtqueue.c +++ b/hw/virtio/vhost-shadow-virtqueue.c @@ -484,6 +484,28 @@ 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) +{ + do { + uint32_t len; + VirtQueueElement *elem =3D vhost_svq_get_buf(svq, &len); + if (elem) { + return len; + } + + /* Make sure we read new used_idx */ + smp_rmb(); + } while (true); +} + /** * Forward used buffers. * --=20 2.31.1