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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id E7130C433EF for ; Tue, 8 Feb 2022 07:41:38 +0000 (UTC) Received: from localhost ([::1]:57768 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nHL7z-0007VQ-R5 for qemu-devel@archiver.kernel.org; Tue, 08 Feb 2022 02:41:34 -0500 Received: from eggs.gnu.org ([209.51.188.92]:49654) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nHKTQ-0003Fx-Mg for qemu-devel@nongnu.org; Tue, 08 Feb 2022 01:59:38 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:28432) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nHKTH-0006k8-L2 for qemu-devel@nongnu.org; Tue, 08 Feb 2022 01:59:31 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1644303521; 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=75Iq94Dp/tXC9KrSfKdcUkCyJNK+H2fJiYTGUK75R5c=; b=dycfAbF7Fn1Tvtu26u8Q0WKZnXHnnysBvmMFx1l0+tJbNYF+TDfZUbiO63+RwpGyMEPMv+ Pg/6RGihMzQ8colglPA3QEa/OmE2WboHzLyvpIq1tjnnhXEEnAGs1Mfn5DLvwD8lYiH93j Zogg5ANC8HzLK+GzUzJ7qtPnCKZo2xY= Received: from mail-pl1-f199.google.com (mail-pl1-f199.google.com [209.85.214.199]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-673-YjEhZs8wO7qjdLxsDVXWrg-1; Tue, 08 Feb 2022 01:58:40 -0500 X-MC-Unique: YjEhZs8wO7qjdLxsDVXWrg-1 Received: by mail-pl1-f199.google.com with SMTP id f9-20020a170902684900b0014cd6059ecdso6909710pln.7 for ; Mon, 07 Feb 2022 22:58:40 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=75Iq94Dp/tXC9KrSfKdcUkCyJNK+H2fJiYTGUK75R5c=; b=hA5utiC5nz5QnlQl3yQBxAkmZ2uA4oRU1d3ZMvfKMty/4dLKfEM3jVfC7b496pm1L1 csVqgRzZ5YN+mVYSIdRb7w/JinbwWm3iqbHCeZPpzUzyKiJ1aY0Psrf0GKXvVnhtUW8C nmzsWH68jpcSEatzI8l9256CQrSZgzR/aG7q3D9wsso8hU7dPDwwTX8+4exWhJ/3Kvp0 djfX+3uQaRH7d0jUgeAphkUuLzVRzNiTEpAt8/cbnByW+Va66GVpMgL4WdGodZzJH4/B vjmmtg+6CCzKuH1kwxFFrjnVj0wKJrVvhu3S7c7F3e7ZwLX7l1sxWfSdkVmhTwxJDNlv TBRQ== X-Gm-Message-State: AOAM531JcUIoMOoUAtEiyL4sganP06f8eHo7mdgKrfHLYr2rXBGzY8J1 xYxVKLgGZiawGJxyL9Qvsln+qDKi/sH+fpVy+4j0+ZCe+AxXsEPoCRle/6aUanzKwdFRL0JqZWE geyBk8rqJxUENxl0= X-Received: by 2002:a17:90b:3ece:: with SMTP id rm14mr2876247pjb.220.1644303519114; Mon, 07 Feb 2022 22:58:39 -0800 (PST) X-Google-Smtp-Source: ABdhPJy1lSSs1vr+wO7cooTPkapSG5GEpiu/r0pjJuh8WXOjGekx015DpYJbEccMJD1ZSDHnD3nXsA== X-Received: by 2002:a17:90b:3ece:: with SMTP id rm14mr2876209pjb.220.1644303518813; Mon, 07 Feb 2022 22:58:38 -0800 (PST) Received: from [10.72.13.12] ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id 20sm1439863pjf.15.2022.02.07.22.58.31 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 07 Feb 2022 22:58:38 -0800 (PST) Message-ID: Date: Tue, 8 Feb 2022 14:58:29 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.5.1 Subject: Re: [PATCH 16/31] vhost: pass queue index to vhost_vq_get_addr To: Eugenio Perez Martin References: <20220121202733.404989-1-eperezma@redhat.com> <20220121202733.404989-17-eperezma@redhat.com> From: Jason Wang In-Reply-To: Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=jasowang@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.129.124; envelope-from=jasowang@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, 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: , Cc: Laurent Vivier , Parav Pandit , Cindy Lu , "Michael S. Tsirkin" , Juan Quintela , Richard Henderson , qemu-level , Gautam Dawar , Markus Armbruster , Eduardo Habkost , Harpreet Singh Anand , Xiao W Wang , Peter Xu , Stefan Hajnoczi , Eli Cohen , Paolo Bonzini , Zhu Lingshan , virtualization , Eric Blake , Stefano Garzarella Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" 在 2022/2/1 上午1:44, Eugenio Perez Martin 写道: > On Sat, Jan 29, 2022 at 9:20 AM Jason Wang wrote: >> >> 在 2022/1/22 上午4:27, Eugenio Pérez 写道: >>> Doing that way allows vhost backend to know what address to return. >>> >>> Signed-off-by: Eugenio Pérez >>> --- >>> hw/virtio/vhost.c | 6 +++--- >>> 1 file changed, 3 insertions(+), 3 deletions(-) >>> >>> diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c >>> index 7b03efccec..64b955ba0c 100644 >>> --- a/hw/virtio/vhost.c >>> +++ b/hw/virtio/vhost.c >>> @@ -798,9 +798,10 @@ static int vhost_virtqueue_set_addr(struct vhost_dev *dev, >>> struct vhost_virtqueue *vq, >>> unsigned idx, bool enable_log) >>> { >>> - struct vhost_vring_addr addr; >>> + struct vhost_vring_addr addr = { >>> + .index = idx, >>> + }; >>> int r; >>> - memset(&addr, 0, sizeof(struct vhost_vring_addr)); >>> >>> if (dev->vhost_ops->vhost_vq_get_addr) { >>> r = dev->vhost_ops->vhost_vq_get_addr(dev, &addr, vq); >>> @@ -813,7 +814,6 @@ static int vhost_virtqueue_set_addr(struct vhost_dev *dev, >>> addr.avail_user_addr = (uint64_t)(unsigned long)vq->avail; >>> addr.used_user_addr = (uint64_t)(unsigned long)vq->used; >>> } >> >> I'm a bit lost in the logic above, any reason we need call >> vhost_vq_get_addr() :) ? >> > It's the way vhost_virtqueue_set_addr works if the backend has a > vhost_vq_get_addr operation (currently, only vhost-vdpa). vhost first > ask the address to the back end and then set it. Right it's because vhost-vdpa doesn't use VA but GPA. But I'm not sure it's worth a dedicated vhost_ops. But consider we introduce shadow virtqueue stuffs, it should be ok now. (In the future, we may consider to generalize non vhost-vdpa specific stuffs to VhostShadowVirtqueue, then we can get rid of this vhost_ops. > > Previously, index was not needed because all the information was in > vhost_virtqueue. However to extract queue index from vhost_virtqueue > is tricky, so I think it's easier to simply have that information at > request, something similar to get_base or get_num when asking vdpa > device. We can extract the index from vq - dev->vqs or something > similar if it's prefered. It looks odd for the caller to tell the index consider vhost_virtqueue is already passed. So I think we need deduce it from vhost_virtqueue as you mentioned here. Thanks > > Thanks! > >> Thanks >> >> >>> - addr.index = idx; >>> addr.log_guest_addr = vq->used_phys; >>> addr.flags = enable_log ? (1 << VHOST_VRING_F_LOG) : 0; >>> r = dev->vhost_ops->vhost_set_vring_addr(dev, &addr);