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 37988C3DA41 for ; Thu, 11 Jul 2024 08:11:15 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sRot8-0004LF-To; Thu, 11 Jul 2024 04:10:50 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sRot7-0004GR-L4 for qemu-devel@nongnu.org; Thu, 11 Jul 2024 04:10:49 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sRot4-0003Hp-NT for qemu-devel@nongnu.org; Thu, 11 Jul 2024 04:10:49 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1720685445; 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=BfM8i/RVIKZAVXEjxV7ooO1ORu1Fs6L5Q+zIos5MOjE=; b=USYCQzO4NmAdbYinANvum/dv7jC3qybKZS7g1L3Z0osd7I0/kO8GHKy9ZmR4u6XymyBesr qx6Qf0kOWj5mfQtRvq9u4x5L2tge2C9heGimPygOuOYmtqoUEVHEGNySCH54KXQN7ECCi6 gAov6A0rLeAih0QwpyyExOcIC35+/aw= Received: from mx-prod-mc-01.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-591-DxaGoiOSPoOQog2Ve9Ya5g-1; Thu, 11 Jul 2024 04:10:40 -0400 X-MC-Unique: DxaGoiOSPoOQog2Ve9Ya5g-1 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (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-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 848C519361AC; Thu, 11 Jul 2024 08:10:39 +0000 (UTC) Received: from localhost (unknown [10.39.192.113]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id F166A1956046; Thu, 11 Jul 2024 08:10:37 +0000 (UTC) Date: Thu, 11 Jul 2024 10:10:36 +0200 From: Stefan Hajnoczi To: Albert Esteve Cc: qemu-devel@nongnu.org, jasowang@redhat.com, david@redhat.com, slp@redhat.com, Alex =?iso-8859-1?Q?Benn=E9e?= , "Michael S. Tsirkin" Subject: Re: [RFC PATCH v2 2/5] vhost_user: Add frontend command for shmem config Message-ID: <20240711081036.GD563880@dynamic-pd01.res.v6.highway.a1.net> References: <20240628145710.1516121-1-aesteve@redhat.com> <20240628145710.1516121-3-aesteve@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="QWvl0FTyJBUg9ZbD" Content-Disposition: inline In-Reply-To: <20240628145710.1516121-3-aesteve@redhat.com> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Received-SPF: pass client-ip=170.10.129.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.144, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org --QWvl0FTyJBUg9ZbD Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Jun 28, 2024 at 04:57:07PM +0200, Albert Esteve wrote: > The frontend can use this command to retrieve > VIRTIO Shared Memory Regions configuration from > the backend. The response contains the number of > shared memory regions, their size, and shmid. >=20 > This is useful when the frontend is unaware of > specific backend type and configuration, > for example, in the `vhost-user-device` case. >=20 > Signed-off-by: Albert Esteve > --- > docs/interop/vhost-user.rst | 31 +++++++++++++++++++++++ > hw/virtio/vhost-user.c | 42 +++++++++++++++++++++++++++++++ > include/hw/virtio/vhost-backend.h | 6 +++++ > include/hw/virtio/vhost-user.h | 1 + > 4 files changed, 80 insertions(+) >=20 > diff --git a/docs/interop/vhost-user.rst b/docs/interop/vhost-user.rst > index d52ba719d5..51f01d1d84 100644 > --- a/docs/interop/vhost-user.rst > +++ b/docs/interop/vhost-user.rst > @@ -348,6 +348,19 @@ Device state transfer parameters > In the future, additional phases might be added e.g. to allow > iterative migration while the device is running. > =20 > +VIRTIO Shared Memory Region configuration > +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > + > ++-------------+---------+------------+----+------------+ > +| num regions | padding | mem size 0 | .. | mem size 7 | > ++-------------+---------+------------+----+------------+ 8 regions may not be enough. The max according to the VIRTIO spec is 256 because virtio-pci uses an 8-bit cap.id field for the shmid. I think the maximum number should be 256 here. (I haven't checked the QEMU vhost-user code to see whether it's reasonable to hardcode to 256 or some logic if needed to dynamically size the buffer depending on the "num regions" field.) > + > +:num regions: a 32-bit number of regions > + > +:padding: 32-bit > + > +:mem size: 64-bit size of VIRTIO Shared Memory Region > + > C structure > ----------- > =20 > @@ -369,6 +382,10 @@ In QEMU the vhost-user message is implemented with t= he following struct: > VhostUserConfig config; > VhostUserVringArea area; > VhostUserInflight inflight; > + VhostUserShared object; > + VhostUserTransferDeviceState transfer_state; > + VhostUserMMap mmap; Why are these added by this patch? Please add them in the same patch where they are introduced. > + VhostUserShMemConfig shmem; > }; > } QEMU_PACKED VhostUserMsg; > =20 > @@ -1051,6 +1068,7 @@ Protocol features > #define VHOST_USER_PROTOCOL_F_XEN_MMAP 17 > #define VHOST_USER_PROTOCOL_F_SHARED_OBJECT 18 > #define VHOST_USER_PROTOCOL_F_DEVICE_STATE 19 > + #define VHOST_USER_PROTOCOL_F_SHMEM 20 > =20 > Front-end message types > ----------------------- > @@ -1725,6 +1743,19 @@ Front-end message types > Using this function requires prior negotiation of the > ``VHOST_USER_PROTOCOL_F_DEVICE_STATE`` feature. > =20 > +``VHOST_USER_GET_SHMEM_CONFIG`` > + :id: 44 > + :equivalent ioctl: N/A > + :request payload: N/A > + :reply payload: ``struct VhostUserShMemConfig`` > + > + When the ``VHOST_USER_PROTOCOL_F_SHMEM`` protocol feature has been > + successfully negotiated, this message can be submitted by the front-end > + to gather the VIRTIO Shared Memory Region configuration. Back-end will= respond > + with the number of VIRTIO Shared Memory Regions it requires, and each = shared memory > + region size in an array. The shared memory IDs are represented by the = index > + of the array. Is the information returned by SHMEM_CONFIG valid and unchanged for the entire lifetime of the vhost-user connection? I think the answer is yes because the enumeration that virtio-pci and virtio-mmio transports support is basically a one-time operation at driver startup and it is static (Shared Memory Regions do not appear or go away at runtime). Please be explicit how VHOST_USER_GET_SHMEM_CONFIG is intended to be used. > + > Back-end message types > ---------------------- > =20 > diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c > index 7ee8a472c6..57406dc8b4 100644 > --- a/hw/virtio/vhost-user.c > +++ b/hw/virtio/vhost-user.c > @@ -104,6 +104,7 @@ typedef enum VhostUserRequest { > VHOST_USER_GET_SHARED_OBJECT =3D 41, > VHOST_USER_SET_DEVICE_STATE_FD =3D 42, > VHOST_USER_CHECK_DEVICE_STATE =3D 43, > + VHOST_USER_GET_SHMEM_CONFIG =3D 44, > VHOST_USER_MAX > } VhostUserRequest; > =20 > @@ -138,6 +139,12 @@ typedef struct VhostUserMemRegMsg { > VhostUserMemoryRegion region; > } VhostUserMemRegMsg; > =20 > +typedef struct VhostUserShMemConfig { > + uint32_t nregions; > + uint32_t padding; > + uint64_t memory_sizes[VHOST_MEMORY_BASELINE_NREGIONS]; > +} VhostUserShMemConfig; > + > typedef struct VhostUserLog { > uint64_t mmap_size; > uint64_t mmap_offset; > @@ -245,6 +252,7 @@ typedef union { > VhostUserShared object; > VhostUserTransferDeviceState transfer_state; > VhostUserMMap mmap; > + VhostUserShMemConfig shmem; > } VhostUserPayload; > =20 > typedef struct VhostUserMsg { > @@ -3136,6 +3144,39 @@ static int vhost_user_check_device_state(struct vh= ost_dev *dev, Error **errp) > return 0; > } > =20 > +static int vhost_user_get_shmem_config(struct vhost_dev *dev, > + int *nregions, > + uint64_t *memory_sizes, > + Error **errp) > +{ > + int ret; > + VhostUserMsg msg =3D { > + .hdr.request =3D VHOST_USER_GET_SHMEM_CONFIG, > + .hdr.flags =3D VHOST_USER_VERSION, > + }; > + > + if (!virtio_has_feature(dev->protocol_features, > + VHOST_USER_PROTOCOL_F_SHMEM)) { > + return 0; > + } > + > + ret =3D vhost_user_write(dev, &msg, NULL, 0); > + if (ret < 0) { > + return ret; > + } > + > + ret =3D vhost_user_read(dev, &msg); > + if (ret < 0) { > + return ret; > + } > + > + *nregions =3D msg.payload.shmem.nregions; Missing input validation from the untrusted vhost-user backend. nregions may be out of range. > + memcpy(memory_sizes, > + &msg.payload.shmem.memory_sizes, > + sizeof(uint64_t) * VHOST_MEMORY_BASELINE_NREGIONS); > + return 0; > +} > + > const VhostOps user_ops =3D { > .backend_type =3D VHOST_BACKEND_TYPE_USER, > .vhost_backend_init =3D vhost_user_backend_init, > @@ -3174,4 +3215,5 @@ const VhostOps user_ops =3D { > .vhost_supports_device_state =3D vhost_user_supports_device_stat= e, > .vhost_set_device_state_fd =3D vhost_user_set_device_state_fd, > .vhost_check_device_state =3D vhost_user_check_device_state, > + .vhost_get_shmem_config =3D vhost_user_get_shmem_config, > }; > diff --git a/include/hw/virtio/vhost-backend.h b/include/hw/virtio/vhost-= backend.h > index 70c2e8ffee..f9c2955420 100644 > --- a/include/hw/virtio/vhost-backend.h > +++ b/include/hw/virtio/vhost-backend.h > @@ -159,6 +159,11 @@ typedef int (*vhost_set_device_state_fd_op)(struct v= host_dev *dev, > int *reply_fd, > Error **errp); > typedef int (*vhost_check_device_state_op)(struct vhost_dev *dev, Error = **errp); > +typedef int (*vhost_get_shmem_config_op)(struct vhost_dev *dev, > + int *nregions, > + uint64_t *memory_sizes, > + Error **errp); > + > =20 > typedef struct VhostOps { > VhostBackendType backend_type; > @@ -214,6 +219,7 @@ typedef struct VhostOps { > vhost_supports_device_state_op vhost_supports_device_state; > vhost_set_device_state_fd_op vhost_set_device_state_fd; > vhost_check_device_state_op vhost_check_device_state; > + vhost_get_shmem_config_op vhost_get_shmem_config; > } VhostOps; > =20 > int vhost_backend_update_device_iotlb(struct vhost_dev *dev, > diff --git a/include/hw/virtio/vhost-user.h b/include/hw/virtio/vhost-use= r.h > index d7c09ffd34..e1b587a908 100644 > --- a/include/hw/virtio/vhost-user.h > +++ b/include/hw/virtio/vhost-user.h > @@ -32,6 +32,7 @@ enum VhostUserProtocolFeature { > /* Feature 17 reserved for VHOST_USER_PROTOCOL_F_XEN_MMAP. */ > VHOST_USER_PROTOCOL_F_SHARED_OBJECT =3D 18, > VHOST_USER_PROTOCOL_F_DEVICE_STATE =3D 19, > + VHOST_USER_PROTOCOL_F_SHMEM =3D 20, > VHOST_USER_PROTOCOL_F_MAX > }; > =20 > --=20 > 2.45.2 >=20 --QWvl0FTyJBUg9ZbD Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAmaPk3wACgkQnKSrs4Gr c8h4eQgAw+FV/mkyYHxhyni8w0p7APFRiJaVXBGoQQv4vHKN7dQmEsQkP/vY2Sfy c23+WdqodYseEsMjYXaTORQlbQBJ6WB6eDAPCa8hc+pp+baKSAiITd+YKXOH0ATC 3BcHT6cNIgP5afUcm5k1/V803m+2zZVnnEtJvuAmtVpRnpgCYoldeH6v4sXDeWsO Wa+j/CBZaq/q5anDmLDjBsFGLd0iDMjBrsmeLxGZcfFTtkdnlVB14Pcl52SDm7hG sjDCh0NNA5jAnwe7I7N21/8Rt4XSNQ2GegKVQOczl5IvwtMS5S3k13Du3nKrKfmA 8/5whJC01zgTq0q+Ezqb/e/bi1GiiA== =qCQv -----END PGP SIGNATURE----- --QWvl0FTyJBUg9ZbD--