From patchwork Fri Nov 20 18:50:57 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Eugenio Perez Martin X-Patchwork-Id: 11921973 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=-15.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 28018C8300B for ; Fri, 20 Nov 2020 18:56:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D81A322464 for ; Fri, 20 Nov 2020 18:56:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="gaezpIIc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729883AbgKTSzv (ORCPT ); Fri, 20 Nov 2020 13:55:51 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:41190 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729799AbgKTSzu (ORCPT ); Fri, 20 Nov 2020 13:55:50 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1605898549; 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=dZxEbXIS4zyXv2m5LGIw7P1HSVQ2S2HneDTGUSzuoD4=; b=gaezpIIcgD92Wl5AM82iwozS3ajF2dMW3DowHwHFa592D6GKwC4T50ETOyc1Az73HWAQGL lcEvQ9ZJ389sCTrxLctbeqEcxKW+p/qJ5yMP6GaswvT7kvHMBpC+XHkdmdRdg2IjTZMEpM isJW0ERJpAWEIX+it78SmmeOluC+LOw= 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-84-TAvJhVXkPzytOL7DCgwuCw-1; Fri, 20 Nov 2020 13:55:46 -0500 X-MC-Unique: TAvJhVXkPzytOL7DCgwuCw-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A68DA8030A3; Fri, 20 Nov 2020 18:55:43 +0000 (UTC) Received: from eperezma.remote.csb (ovpn-112-88.ams2.redhat.com [10.36.112.88]) by smtp.corp.redhat.com (Postfix) with ESMTP id 146EB5C1D5; Fri, 20 Nov 2020 18:55:30 +0000 (UTC) From: =?utf-8?q?Eugenio_P=C3=A9rez?= To: qemu-devel@nongnu.org Cc: Lars Ganrot , virtualization@lists.linux-foundation.org, Salil Mehta , "Michael S. Tsirkin" , Liran Alon , Rob Miller , Max Gurtovoy , Alex Barba , Stefan Hajnoczi , Jim Harford , Jason Wang , Harpreet Singh Anand , Christophe Fontaine , vm , Daniel Daly , Michael Lilja , Stefano Garzarella , Nitin Shrivastav , Lee Ballard , Dmytro Kazantsev , Juan Quintela , kvm@vger.kernel.org, Howard Cai , Xiao W Wang , Sean Mooney , Parav Pandit , Eli Cohen , Siwei Liu , Stephen Finucane Subject: [RFC PATCH 19/27] vhost: add vhost_vring_get_buf_rcu Date: Fri, 20 Nov 2020 19:50:57 +0100 Message-Id: <20201120185105.279030-20-eperezma@redhat.com> In-Reply-To: <20201120185105.279030-1-eperezma@redhat.com> References: <20201120185105.279030-1-eperezma@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Signed-off-by: Eugenio Pérez --- hw/virtio/vhost-sw-lm-ring.h | 1 + hw/virtio/vhost-sw-lm-ring.c | 29 +++++++++++++++++++++++++++++ 2 files changed, 30 insertions(+) diff --git a/hw/virtio/vhost-sw-lm-ring.h b/hw/virtio/vhost-sw-lm-ring.h index 03257d60c1..429a125558 100644 --- a/hw/virtio/vhost-sw-lm-ring.h +++ b/hw/virtio/vhost-sw-lm-ring.h @@ -19,6 +19,7 @@ typedef struct VhostShadowVirtqueue VhostShadowVirtqueue; bool vhost_vring_kick(VhostShadowVirtqueue *vq); int vhost_vring_add(VhostShadowVirtqueue *vq, VirtQueueElement *elem); +VirtQueueElement *vhost_vring_get_buf_rcu(VhostShadowVirtqueue *vq, size_t sz); /* Called within rcu_read_lock(). */ void vhost_vring_set_notification_rcu(VhostShadowVirtqueue *vq, bool enable); diff --git a/hw/virtio/vhost-sw-lm-ring.c b/hw/virtio/vhost-sw-lm-ring.c index 3652889d8e..4fafd1b278 100644 --- a/hw/virtio/vhost-sw-lm-ring.c +++ b/hw/virtio/vhost-sw-lm-ring.c @@ -187,6 +187,35 @@ int vhost_vring_add(VhostShadowVirtqueue *vq, VirtQueueElement *elem) return 0; } +VirtQueueElement *vhost_vring_get_buf_rcu(VhostShadowVirtqueue *vq, size_t sz) +{ + const vring_used_t *used = vq->vring.used; + VirtQueueElement *ret; + vring_used_elem_t used_elem; + uint16_t last_used; + + if (!vhost_vring_poll_rcu(vq)) { + return NULL; + } + + last_used = vq->used_idx & (vq->vring.num - 1); + used_elem.id = virtio_tswap32(vq->vdev, used->ring[last_used].id); + used_elem.len = virtio_tswap32(vq->vdev, used->ring[last_used].len); + + if (unlikely(used_elem.id >= vq->vring.num)) { + virtio_error(vq->vdev, "Device says index %u is available", + used_elem.id); + return NULL; + } + + ret = vq->ring_id_maps[used_elem.id]; + ret->len = used_elem.len; + + vq->used_idx++; + + return ret; +} + void vhost_vring_write_addr(const VhostShadowVirtqueue *vq, struct vhost_vring_addr *addr) {