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 ECAE04682B for ; Fri, 6 Jun 2025 17:10:43 +0200 (CEST) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id E54D1406B4; Fri, 6 Jun 2025 17:10:43 +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 4216640684 for ; Fri, 6 Jun 2025 17:10:42 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1749222641; 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:autocrypt:autocrypt; bh=chTgfri7wrTOXvjQaPIMSTb8W08W34MhvHWsfqNdWm8=; b=WL6rnRMQPBgQqqJ0u3dBU0jji5gG4AQT+G99YxRxwFt/NMMAh2bomn1xLBaARVPsPraao+ mhl1l1nsz24hdCAfyjr+9ibm/UIS5hfRh2gyTQffeBsgCm8so8cHysfUfD8WDdQWqkUxi5 dkSRv7FJ+4mJbFqNsSMmW47s1NlN6l8= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-518-49lIp9wNMiGo0CDfoRMfFg-1; Fri, 06 Jun 2025 11:10:38 -0400 X-MC-Unique: 49lIp9wNMiGo0CDfoRMfFg-1 X-Mimecast-MFC-AGG-ID: 49lIp9wNMiGo0CDfoRMfFg_1749222637 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id BA8231956057; Fri, 6 Jun 2025 15:10:37 +0000 (UTC) Received: from [10.45.242.3] (unknown [10.45.242.3]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 9408030001B7; Fri, 6 Jun 2025 15:10:35 +0000 (UTC) Message-ID: <5076b1c0-1848-405c-ae27-00e3505a2733@redhat.com> Date: Fri, 6 Jun 2025 17:10:32 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 0/2] Search the split vq desc and avail in RO areas To: David Marchand , Eugenio Perez Martin Cc: dev@dpdk.org, Chenbo Xia , stable@dpdk.org References: <20250605113552.918120-1-eperezma@redhat.com> From: Maxime Coquelin Autocrypt: addr=maxime.coquelin@redhat.com; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-BeenThere: stable@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: patches for DPDK stable branches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: stable-bounces@dpdk.org On 6/6/25 4:20 PM, David Marchand wrote: > On Thu, Jun 5, 2025 at 4:55 PM Eugenio Perez Martin wrote: >> >> On Thu, Jun 5, 2025 at 1:50 PM David Marchand wrote: >>> >>> On Thu, Jun 5, 2025 at 1:36 PM Eugenio Pérez wrote: >>>> >>>> QEMU's shadow virtqueue and VDUSE exposes these areas as read-only. If >>>> we don't change it, vhost_iova_to_vva do not consider them as valid and >>>> returns that they're not found. >>>> >>>> Eugenio Pérez (2): >>>> vhost: search the split vq desc and avail in RO areas >>>> vhost: search the packed vq driver area in RO areas >>>> >>>> lib/vhost/vhost.c | 6 +++--- >>>> 1 file changed, 3 insertions(+), 3 deletions(-) >>> >>> At a quick glance, no need for two patches. >>> >> >> Sure I can respin with both squashed. >> >>> Sorry, the implication of this issue is not clear to me. >>> What is the impact from a user pov? >>> >> >> QEMU maps the CVQ descriptors and avail vring through as read only >> maps in the case of vDPA. But DPDK is looking for them with RW >> permissions, so the vhost_iova_to_vva function never selects the right >> one as valid. >> >> Looking for them with RO still picks the map if it is mapped as RW, >> but the reverse is not true. > > Ok, thanks. > Well, it's better, but still hard to tell how this impacts existing > usecases :-). > After discussing with Maxime, I understand that the shadow CVQ just > can't work => blocking multi queue support with vduse for example. > This is the type of high level impact I was looking for. > >> Let me know if you want me to respin the series with this comment too! > > Ideally yes, but maybe Maxime can do it when applying. > > Yes, I can rework the commit message while applying. Thanks, Maxime