From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DE4EA2DECB2 for ; Tue, 28 Jul 2026 15:23:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785252207; cv=none; b=CxjVSOtdHWVP/oIX1PV6Q2Jo5XzjBNdchVslaCT1YOVn/FTk5Be79iO1Bv4vvrPW3yKIcFP2yFsZ5xZaikyuswo8wvsyR7UFt8WRWUho+oRqi1TrtAFFl+wcY4tkJbLvcNPoaObpzVITXgKe2wj0tV0QO6PT++lzO/PUw06rrQ8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785252207; c=relaxed/simple; bh=oCHK2PqbVSW7OrHbcjL6A0t2l24DQfH2IyB4jPoxPNY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=cbR7470UCG/AGEHhZvuPgqByGd8B9xKcITpDdXnjp7gKKClNZO1Js39uh9EKeZSPcaNr+9JXZU2hCKgaIU0faeq3hy1PJGFPKYCe3UPmIO9NLDnRu6/SGosIyiZ8i9EbrsO22g/kRTOgbJH0O4X++Kf13XP738jN2f23OjyogRQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=aizlnjVX; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="aizlnjVX" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1785252204; 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: in-reply-to:in-reply-to:references:references; bh=yGLmE0Uup5xWQ2G+SyVEbIDUzauE43uCgyclhivM0xc=; b=aizlnjVXAm9h3STdP2wQllq0/bFdnuOI0pseQavg2Mf5wxTePfsLjIG59dRnqSF8Nwmbe6 sImmBChyWcw0judn84nshBflW9SD6X3ycoQQ330uLdm6DK4X9vNZqTWB0RVGWWircJVE4I aqzoE5RlVa/38FHx2esUlBJ+NCmEYpU= 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-605-qGo7YqOsNRW6cQPfrLF7kQ-1; Tue, 28 Jul 2026 11:23:18 -0400 X-MC-Unique: qGo7YqOsNRW6cQPfrLF7kQ-1 X-Mimecast-MFC-AGG-ID: qGo7YqOsNRW6cQPfrLF7kQ_1785252194 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (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 6582E1956058; Tue, 28 Jul 2026 15:23:12 +0000 (UTC) Received: from localhost (unknown [10.2.16.73]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 4D3D818004AD; Tue, 28 Jul 2026 15:23:09 +0000 (UTC) Date: Tue, 28 Jul 2026 11:23:08 -0400 From: Stefan Hajnoczi To: Connor Kite Cc: qemu-devel@nongnu.org, "Michael S. Tsirkin" , Stefano Garzarella , Alex =?iso-8859-1?Q?Benn=E9e?= , Viresh Kumar , Gerd Hoffmann , Mathieu Poirier , Manos Pitsidianakis , Haixu Cui , Raphael Norwitz , Kevin Wolf , Hanna Reitz , =?iso-8859-1?Q?Marc-Andr=E9?= Lureau , Paolo Bonzini , Fam Zheng , Milan Zamazal , Akihiko Odaki , Dmitry Osipenko , qemu-block@nongnu.org, virtio-fs@lists.linux.dev, "Gonglei (Arei)" , zhenwei pi , Daniel =?iso-8859-1?Q?P=2E_Berrang=E9?= , Eric Blake , Markus Armbruster , Jason Wang , Peter Xu , Eugenio =?iso-8859-1?Q?P=E9rez?= , Alyssa Ross , Demi Marie Obenour Subject: Re: [PATCH RFC 09/15] hw/virtio/vhost-shadow-virtqueue: specified vring placement Message-ID: <20260728152308.GG371693@fedora> References: <20260723-vhost-user-isolated-memory-v1-0-6b97c439eb28@gmail.com> <20260723-vhost-user-isolated-memory-v1-9-6b97c439eb28@gmail.com> Precedence: bulk X-Mailing-List: virtio-fs@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="Dl4fy5/Nk4W7j/qR" Content-Disposition: inline In-Reply-To: <20260723-vhost-user-isolated-memory-v1-9-6b97c439eb28@gmail.com> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 --Dl4fy5/Nk4W7j/qR Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Jul 23, 2026 at 03:30:08PM -0700, Connor Kite wrote: > By default svq vrings are placed in an anonymous memory map. As svqs > will be leveraged to enable memory isolation in vhost-user, it is useful > to be able to place the vrings in a shared isolation memory region. >=20 > Adds the option to specify vring placement by providing a vring base > address before starting the svq. >=20 > Signed-off-by: Connor Kite > --- > hw/virtio/vhost-shadow-virtqueue.c | 22 +++++++++++++++------- > hw/virtio/vhost-shadow-virtqueue.h | 3 +++ > 2 files changed, 18 insertions(+), 7 deletions(-) >=20 > diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-= virtqueue.c > index eb86c1ee37..9e3c359f50 100644 > --- a/hw/virtio/vhost-shadow-virtqueue.c > +++ b/hw/virtio/vhost-shadow-virtqueue.c > @@ -857,14 +857,21 @@ void vhost_svq_start(VhostShadowVirtqueue *svq, Vir= tIODevice *vdev, > =20 > svq->vring.num =3D virtio_queue_get_num(vdev, virtio_get_queue_index= (vq)); > svq->num_free =3D svq->vring.num; > - svq->vring.desc =3D mmap(NULL, vhost_svq_driver_area_size(svq), > - PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANON= YMOUS, > - -1, 0); > desc_size =3D sizeof(vring_desc_t) * svq->vring.num; > - svq->vring.avail =3D (void *)((char *)svq->vring.desc + desc_size); > - svq->vring.used =3D mmap(NULL, vhost_svq_device_area_size(svq), > - PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANON= YMOUS, > - -1, 0); > + if (svq->base_addr =3D=3D NULL) { > + svq->vring.desc =3D mmap(NULL, vhost_svq_driver_area_size(svq), > + PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANO= NYMOUS, > + -1, 0); > + svq->vring.avail =3D (void *)((char *)svq->vring.desc + desc_siz= e); > + svq->vring.used =3D mmap(NULL, vhost_svq_device_area_size(svq), > + PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANO= NYMOUS, > + -1, 0); > + } else { > + svq->vring.desc =3D (void *) svq->base_addr; > + svq->vring.avail =3D (void *)((char *)svq->vring.desc + desc_siz= e); > + svq->vring.used =3D (void *)((char *)svq->base_addr + > + vhost_svq_driver_area_size(svq)); > + } > svq->desc_state =3D g_new0(SVQDescState, svq->vring.num); > if (virtio_vdev_has_feature(svq->vdev, VIRTIO_F_IN_ORDER)) { > svq->batch_last.id =3D VIRTIO_RING_NOT_IN_BATCH; > @@ -929,6 +936,7 @@ VhostShadowVirtqueue *vhost_svq_new(const VhostShadow= VirtqueueOps *ops, > event_notifier_init_fd(&svq->svq_kick, VHOST_FILE_UNBIND); > svq->ops =3D ops; > svq->ops_opaque =3D ops_opaque; > + svq->base_addr =3D NULL; > return svq; > } > =20 > diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-= virtqueue.h > index ccfeee36d7..39f69e6455 100644 > --- a/hw/virtio/vhost-shadow-virtqueue.h > +++ b/hw/virtio/vhost-shadow-virtqueue.h > @@ -148,6 +148,9 @@ typedef struct VhostShadowVirtqueue { > =20 > /* Size of SVQ vring free descriptors */ > uint16_t num_free; > + > + /* Location assigned to vrings if not in default anon memory map*/ > + hwaddr *base_addr; Why is base_addr a hwaddr? This is QEMU memory, not guest RAM. I expected this to be void *. A size needs to be at least documented here to reduce the chance of memory bugs. Even better would be an interface like vhost_svq_vring_total_size() so the caller can fetch the number of bytes before allocating the memory. --Dl4fy5/Nk4W7j/qR Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iQEzBAEBCgAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAmpoyVwACgkQnKSrs4Gr c8jUuwgAvMc/G3tOhj0RTFEXylyhHMcyDAfcvVg+19MNnwq8RSuEjpwK7ongL+Do s3rzWOVKWxQS8RMFhq0E1zXoLWZ0+nt3Ziqi2XBOj28SEiO3eZyfXMQ6lC1UYo1i ZiN0+qHov/H69XAb8cKJgt4xKyiLhVEZfC/DKBzNzVOiFHApRfzdPQapfqTXA4PJ 5z0v+rRysNK9dCaLDf6hqlXki1xWm3M877IeDEztVtof0FolUwLgy4DM9r8lwEdi efKoa9g6Jb083QGMMCKEzXR5wkxvrIVsbIc/OonhN8XDNjJNPpiaZeLlDj0WddGb BECKOD1lZ+YB9/soytLlda2bjV2M8g== =jc6J -----END PGP SIGNATURE----- --Dl4fy5/Nk4W7j/qR--