From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 0EF5C46D5B; Mon, 18 Aug 2025 14:56:34 +0200 (CEST) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id F35E3402ED; Mon, 18 Aug 2025 14:56:32 +0200 (CEST) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by mails.dpdk.org (Postfix) with ESMTP id 8AA2E40262 for ; Mon, 18 Aug 2025 14:56:31 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1755521790; 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=X2g75/fb8wPPQSpZzEDDWs4QPYRv9IS3MW74fdqNrl4=; b=TgZE7toRhvS2T1TiQOp2n1A+NcB74bJQOZq2242bpDEUABCdtSMf9jX52nwC/DxrEcWGvs /Ub7gG/obmWcq+DDfWnmtxtqu6mqaWLnoiixmohhuzOT2Dsdrgd6kxTyAerw+e04hdSj0L GkvIavaHm/KOTbnLHSkjxXrGfiRH9Us= Received: from mail-lf1-f71.google.com (mail-lf1-f71.google.com [209.85.167.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-608-BUUVcAOtPna36_UVQVi87Q-1; Mon, 18 Aug 2025 08:56:29 -0400 X-MC-Unique: BUUVcAOtPna36_UVQVi87Q-1 X-Mimecast-MFC-AGG-ID: BUUVcAOtPna36_UVQVi87Q_1755521787 Received: by mail-lf1-f71.google.com with SMTP id 2adb3069b0e04-55ce520c261so1766261e87.1 for ; Mon, 18 Aug 2025 05:56:28 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1755521787; x=1756126587; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=X2g75/fb8wPPQSpZzEDDWs4QPYRv9IS3MW74fdqNrl4=; b=NTNuzOJL9RVBFtZWW3oZHD6LTsQVpQQtpi4IBU40yp2qne32AOQqyQNSYlat/HbBPz gKjE/ndCvYAkhlVwE/vc3wpxKRoSd860E7CqG+wfHd0g/vUpwET7KHZPuXuTDQzjCQ71 htbRkl0tQ3cyXbBOee9VJkhA+uM0poFsWEy4trFg/tXZSzbxKu1rXsqU1P37QwjSej4L aqi16ztLLKr39UMAS7gMxp8tNnzuektWDTBaNE4qZDjA4ngOQipit7bAeNTv6spi/6rT iiAvjfYameZBL9QxMXtPa/8G734xZvrWsHniTZPKkYOpcuIqmAB6KNeQ8XLPgBR2+KLv EMqQ== X-Gm-Message-State: AOJu0YyaE98P6Gs5RkeJoIUotTXYzj6FmSvi9vkwiAZ1AhwYsxjefHwO 3lMi3Jdqs6S7SkpsEVBiFDn9dCKOl12ZJ6G2NV3YYdFOAOLUq9LMZnoA3AaYjtQUj5nII94E6Yo 1FnZ+5fO23eFyrep17NrxLvf9Bl+Jvq6ZWhnszAeMUu3c/1uAhlz9aT3Rj58oh29bVRe35QjtGP 5WtkZHWbyqQT4sBeSJprw= X-Gm-Gg: ASbGncul3brkZLlfQpYXWgsXLeW/jf2ozM6pBom3CyoN+v8UfuDgJwrpHLiG/L9hOwu 1jl4czA8gzQqvN6G2U3p5l4UzlDbSFyQhKgxBAFfSbgXlQaFmekrpoZXxusK3ZdMRVtdGbW8CZV 5e1w6EQgkkKwfqaWjdhbex97M= X-Received: by 2002:ac2:5687:0:b0:55a:826d:fa31 with SMTP id 2adb3069b0e04-55cf2cdcfdemr2477872e87.37.1755521787281; Mon, 18 Aug 2025 05:56:27 -0700 (PDT) X-Google-Smtp-Source: AGHT+IHX9JoMEFiK7JsIRMBQkL7/qNGWlL9Ls3Pt1oop6OilD0QmvqNUbq/pHbxOlG/AJ1o9LqXAUGi3yPgimyuvRZg= X-Received: by 2002:ac2:5687:0:b0:55a:826d:fa31 with SMTP id 2adb3069b0e04-55cf2cdcfdemr2477861e87.37.1755521786793; Mon, 18 Aug 2025 05:56:26 -0700 (PDT) MIME-Version: 1.0 References: <20250805083657.1227817-1-maxime.coquelin@redhat.com> In-Reply-To: <20250805083657.1227817-1-maxime.coquelin@redhat.com> From: David Marchand Date: Mon, 18 Aug 2025 14:56:15 +0200 X-Gm-Features: Ac12FXxlJ_mpToMWbilXyiOr9EEieL1FdEwCrdW5zFomB64aCAsUSEVUqnmFEsQ Message-ID: Subject: Re: [PATCH] net/virtio-user: fix used ring address calculation To: Maxime Coquelin Cc: dev@dpdk.org, amorenoz@redhat.com, chenbox@nvidia.com, schalla@marvell.com, stable@dpdk.org X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: bgJP_nhDFZ6Fc4LgKNGxeMROC9tPAlk4owfAPeePML0_1755521787 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org On Tue, Aug 5, 2025 at 10:37=E2=80=AFAM Maxime Coquelin wrote: > > This patch fixes the used ring address calculation, to > avoid Vhost-vDPA backends (such as VDUSE) to fail while > trying to translate it. Maybe update the patch title to reflect that this issue affects vhost-vdpa backend? > > Fixes: 666ef294ddf7 ("net/virtio-user: share descriptor IOVA to backend") > Cc: stable@dpdk.org > > Reported-by: Adrian Moreno > Signed-off-by: Maxime Coquelin > --- > drivers/net/virtio/virtio_user/virtio_user_dev.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c b/drivers/n= et/virtio/virtio_user/virtio_user_dev.c > index 187f81b066..7789f337f6 100644 > --- a/drivers/net/virtio/virtio_user/virtio_user_dev.c > +++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c > @@ -149,7 +149,8 @@ virtio_user_kick_queue(struct virtio_user_dev *dev, u= int32_t queue_sel) > } else { > desc_addr =3D vring->desc_iova; > avail_addr =3D desc_addr + vring->num * sizeof(struct vri= ng_desc); > - used_addr =3D RTE_ALIGN_CEIL((uintptr_t)(&vring->avail->r= ing[vring->num]), > + used_addr =3D RTE_ALIGN_CEIL(avail_addr + offsetof(struct= vring_avail, > + ring[vring->num]), > VIRTIO_VRING_ALIGN); The fix looks good to me, but I would go one step further (as a followup maybe?). I see no good reason for computing again the addresses in the kick helper, while those addresses should be set once and for all at "setup" time. Only an offset needs to be applied to account for iova stuff. What do you think of something like: diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c b/drivers/net/virtio/virtio_user/virtio_user_dev.c index 187f81b066..dcb702ace3 100644 --- a/drivers/net/virtio/virtio_user/virtio_user_dev.c +++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c @@ -118,7 +118,7 @@ virtio_user_kick_queue(struct virtio_user_dev *dev, uint32_t queue_sel) struct vhost_vring_state state; struct vring *vring =3D &dev->vrings.split[queue_sel]; struct vring_packed *pq_vring =3D &dev->vrings.packed[queue_sel]; - uint64_t desc_addr, avail_addr, used_addr; + uint64_t desc_addr, desc_iova_addr, avail_addr, used_addr; struct vhost_vring_addr addr =3D { .index =3D queue_sel, .log_guest_addr =3D 0, @@ -138,25 +138,22 @@ virtio_user_kick_queue(struct virtio_user_dev *dev, uint32_t queue_sel) } if (dev->features & (1ULL << VIRTIO_F_RING_PACKED)) { - desc_addr =3D pq_vring->desc_iova; - avail_addr =3D desc_addr + pq_vring->num * sizeof(struct vring_packed_desc); - used_addr =3D RTE_ALIGN_CEIL(avail_addr + sizeof(struct vring_packed_desc_event), - VIRTIO_VRING_ALIGN); - - addr.desc_user_addr =3D desc_addr; - addr.avail_user_addr =3D avail_addr; - addr.used_user_addr =3D used_addr; + desc_iova_addr =3D pq_vring->desc_iova; + desc_addr =3D (uint64_t)(uintptr_t)pq_vring->desc; + avail_addr =3D (uint64_t)(uintptr_t)pq_vring->driver; + used_addr =3D (uint64_t)(uintptr_t)pq_vring->device; + } else { - desc_addr =3D vring->desc_iova; - avail_addr =3D desc_addr + vring->num * sizeof(struct vring= _desc); - used_addr =3D RTE_ALIGN_CEIL((uintptr_t)(&vring->avail->ring[vring->num]), - VIRTIO_VRING_ALIGN); - - addr.desc_user_addr =3D desc_addr; - addr.avail_user_addr =3D avail_addr; - addr.used_user_addr =3D used_addr; + desc_iova_addr =3D vring->desc_iova; + desc_addr =3D (uint64_t)(uintptr_t)vring->desc; + avail_addr =3D (uint64_t)(uintptr_t)vring->avail; + used_addr =3D (uint64_t)(uintptr_t)vring->used; } + addr.desc_user_addr =3D desc_iova_addr; + addr.avail_user_addr =3D (desc_iova_addr - desc_addr) + avail_addr; + addr.used_user_addr =3D (desc_iova_addr - desc_addr) + used_addr; + state.index =3D queue_sel; state.num =3D vring->num; ret =3D dev->ops->set_vring_num(dev, &state); --=20 David Marchand