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 C23E2C02198 for ; Tue, 18 Feb 2025 06:43:57 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tkHKU-0008Ob-Uu; Tue, 18 Feb 2025 01:43:38 -0500 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 1tkHKT-0008OD-3b for qemu-devel@nongnu.org; Tue, 18 Feb 2025 01:43:37 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tkHKP-0006VP-Il for qemu-devel@nongnu.org; Tue, 18 Feb 2025 01:43:36 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1739861012; 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=OVtDSZ1506FjnGTKVvJG4Lz5SBrlPSjx9E7HpfD/LYU=; b=FJyTLgAPYfEkyQOJX/yFZMCbktak0bWcFhJs4A8B7GBm7E6Ybhy8Iy/CtLMl0URbfxqMoU hUcbfEoI13W+KXSUBSNWHGvwcGFIwyBUrFTms/w/od4U8cNV9PDAA7dUmzTuDQUDOLbte4 BgyLtivsafd4sU36T7CCPFzefTgevMA= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-648-YoOEPDQ-NJGSTK9NjhxTpA-1; Tue, 18 Feb 2025 01:43:27 -0500 X-MC-Unique: YoOEPDQ-NJGSTK9NjhxTpA-1 X-Mimecast-MFC-AGG-ID: YoOEPDQ-NJGSTK9NjhxTpA_1739861006 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (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-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 270521800373; Tue, 18 Feb 2025 06:43:26 +0000 (UTC) Received: from localhost (unknown [10.2.16.60]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 143BC180056F; Tue, 18 Feb 2025 06:43:23 +0000 (UTC) Date: Tue, 18 Feb 2025 14:43:21 +0800 From: Stefan Hajnoczi To: Albert Esteve Cc: qemu-devel@nongnu.org, slp@redhat.com, stevensd@chromium.org, Alex =?iso-8859-1?Q?Benn=E9e?= , Stefano Garzarella , david@redhat.com, hi@alyssa.is, mst@redhat.com, jasowang@redhat.com Subject: Re: [PATCH v4 1/9] vhost-user: Add VirtIO Shared Memory map request Message-ID: <20250218064321.GE10767@fedora> References: <20250217164012.246727-1-aesteve@redhat.com> <20250217164012.246727-2-aesteve@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="n+QqPn/txEljMN+E" Content-Disposition: inline In-Reply-To: <20250217164012.246727-2-aesteve@redhat.com> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Received-SPF: pass client-ip=170.10.133.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 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, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=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 --n+QqPn/txEljMN+E Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Feb 17, 2025 at 05:40:04PM +0100, Albert Esteve wrote: > Add SHMEM_MAP/UNMAP requests to vhost-user to > handle VIRTIO Shared Memory mappings. >=20 > This request allows backends to dynamically map > fds into a VIRTIO Shared Memory Region indentified > by its `shmid`. The map is performed by calling > `memory_region_init_ram_from_fd` and adding the > new region as a subregion of the shmem container > MR. Then, the fd memory is advertised to the > driver as a base addres + offset, so it can be > read/written (depending on the mmap flags > requested) while it is valid. >=20 > The backend can unmap the memory range > in a given VIRTIO Shared Memory Region (again, > identified by its `shmid`), to free it. > Upon receiving this message, the front-end > must delete the MR as a subregion of > the shmem container region and free its > resources. >=20 > Note that commit all these operations need > to be delayed to after we respond the request > to the backend to avoid deadlocks. >=20 > The device model needs to create VirtSharedMemory > instances for the VirtIO Shared Memory Regions > and add them to the `VirtIODevice` instance. >=20 > Signed-off-by: Albert Esteve > --- > hw/virtio/vhost-user.c | 134 ++++++++++++++++++++++ > hw/virtio/virtio.c | 81 +++++++++++++ > include/hw/virtio/virtio.h | 27 +++++ > subprojects/libvhost-user/libvhost-user.c | 70 +++++++++++ > subprojects/libvhost-user/libvhost-user.h | 55 +++++++++ > 5 files changed, 367 insertions(+) >=20 > diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c > index 267b612587..d88e6f8c3c 100644 > --- a/hw/virtio/vhost-user.c > +++ b/hw/virtio/vhost-user.c > @@ -115,6 +115,8 @@ typedef enum VhostUserBackendRequest { > VHOST_USER_BACKEND_SHARED_OBJECT_ADD =3D 6, > VHOST_USER_BACKEND_SHARED_OBJECT_REMOVE =3D 7, > VHOST_USER_BACKEND_SHARED_OBJECT_LOOKUP =3D 8, > + VHOST_USER_BACKEND_SHMEM_MAP =3D 9, > + VHOST_USER_BACKEND_SHMEM_UNMAP =3D 10, > VHOST_USER_BACKEND_MAX > } VhostUserBackendRequest; > =20 > @@ -192,6 +194,24 @@ typedef struct VhostUserShared { > unsigned char uuid[16]; > } VhostUserShared; > =20 > +/* For the flags field of VhostUserMMap */ > +#define VHOST_USER_FLAG_MAP_R (1u << 0) > +#define VHOST_USER_FLAG_MAP_W (1u << 1) > + > +typedef struct { > + /* VIRTIO Shared Memory Region ID */ > + uint8_t shmid; > + uint8_t padding[7]; > + /* File offset */ > + uint64_t fd_offset; > + /* Offset within the VIRTIO Shared Memory Region */ > + uint64_t shm_offset; > + /* Size of the mapping */ > + uint64_t len; > + /* Flags for the mmap operation, from VHOST_USER_FLAG_* */ > + uint64_t flags; > +} VhostUserMMap; > + > typedef struct { > VhostUserRequest request; > =20 > @@ -224,6 +244,7 @@ typedef union { > VhostUserInflight inflight; > VhostUserShared object; > VhostUserTransferDeviceState transfer_state; > + VhostUserMMap mmap; > } VhostUserPayload; > =20 > typedef struct VhostUserMsg { > @@ -1770,6 +1791,111 @@ vhost_user_backend_handle_shared_object_lookup(st= ruct vhost_user *u, > return 0; > } > =20 > +static int > +vhost_user_backend_handle_shmem_map(struct vhost_dev *dev, > + QIOChannel *ioc, > + VhostUserHeader *hdr, > + VhostUserPayload *payload, > + int fd, Error **errp) > +{ > + VirtSharedMemory *shmem =3D NULL; > + VhostUserMMap *vu_mmap =3D &payload->mmap; > + g_autoptr(GString) shm_name =3D g_string_new(NULL); > + > + if (fd < 0) { > + error_report("Bad fd for map"); > + return -EBADF; > + } > + > + if (!dev->vdev->shmem_list || > + dev->vdev->n_shmem_regions <=3D vu_mmap->shmid) { > + error_report("Device only has %d VIRTIO Shared Memory Regions. " > + "Requested ID: %d", > + dev->vdev->n_shmem_regions, vu_mmap->shmid); > + return -EFAULT; > + } > + > + shmem =3D &dev->vdev->shmem_list[vu_mmap->shmid]; > + > + if (!shmem) { > + error_report("VIRTIO Shared Memory Region at " > + "ID %d unitialized", vu_mmap->shmid); > + return -EFAULT; > + } > + > + if ((vu_mmap->shm_offset + vu_mmap->len) < vu_mmap->len || > + (vu_mmap->shm_offset + vu_mmap->len) > shmem->mr->size) { > + error_report("Bad offset/len for mmap %" PRIx64 "+%" PRIx64, > + vu_mmap->shm_offset, vu_mmap->len); > + return -EFAULT; > + } > + > + g_string_printf(shm_name, "virtio-shm%i-%lu", > + vu_mmap->shmid, vu_mmap->shm_offset); > + > + memory_region_transaction_begin(); > + virtio_add_shmem_map(shmem, shm_name->str, vu_mmap->shm_offset, > + vu_mmap->fd_offset, vu_mmap->len, fd, errp); Error handling is missing. In particular, if virtio_add_shmem_map() sets errp due to an error, then vhost_user_send_resp() will crash if it also needs to set the error. An Error object can only be filled in once. > + > + hdr->size =3D sizeof(payload->u64); > + vhost_user_send_resp(ioc, hdr, payload, errp); payload->u64 has not been initialized. It contains the contents of payload->mmap, which is not the u64 return value that must be sent here. I think something like the following is necessary: payload->u64 =3D 0; > + memory_region_transaction_commit(); > + > + return 0; > +} > + > +static int > +vhost_user_backend_handle_shmem_unmap(struct vhost_dev *dev, > + QIOChannel *ioc, > + VhostUserHeader *hdr, > + VhostUserPayload *payload, > + Error **errp) > +{ > + VirtSharedMemory *shmem =3D NULL; > + MappedMemoryRegion *mmap =3D NULL; > + VhostUserMMap *vu_mmap =3D &payload->mmap; > + > + if (!dev->vdev->shmem_list || > + dev->vdev->n_shmem_regions <=3D vu_mmap->shmid) { > + error_report("Device only has %d VIRTIO Shared Memory Regions. " > + "Requested ID: %d", > + dev->vdev->n_shmem_regions, vu_mmap->shmid); > + return -EFAULT; > + } > + > + shmem =3D &dev->vdev->shmem_list[vu_mmap->shmid]; > + > + if (!shmem) { > + error_report("VIRTIO Shared Memory Region at " > + "ID %d unitialized", vu_mmap->shmid); > + return -EFAULT; > + } > + > + if ((vu_mmap->shm_offset + vu_mmap->len) < vu_mmap->len || > + (vu_mmap->shm_offset + vu_mmap->len) > shmem->mr->size) { > + error_report("Bad offset/len for unmmap %" PRIx64 "+%" PRIx64, > + vu_mmap->shm_offset, vu_mmap->len); > + return -EFAULT; > + } > + > + mmap =3D virtio_find_shmem_map(shmem, vu_mmap->shm_offset, vu_mmap->= len); > + if (!mmap) { > + return -EFAULT; > + } > + > + memory_region_transaction_begin(); > + memory_region_del_subregion(shmem->mr, mmap->mem); > + > + hdr->size =3D sizeof(payload->u64); > + vhost_user_send_resp(ioc, hdr, payload, errp); Same uninitialized payload->u64 issue here. > + memory_region_transaction_commit(); > + > + /* Free the MemoryRegion only after vhost_commit */ > + virtio_del_shmem_map(shmem, vu_mmap->shm_offset, vu_mmap->len); > + > + return 0; > +} > + > static void close_backend_channel(struct vhost_user *u) > { > g_source_destroy(u->backend_src); > @@ -1837,6 +1963,14 @@ static gboolean backend_read(QIOChannel *ioc, GIOC= ondition condition, > case VHOST_USER_BACKEND_SHARED_OBJECT_LOOKUP: > ret =3D vhost_user_backend_handle_shared_object_lookup(dev->opaq= ue, ioc, > &hdr, &payl= oad); > + case VHOST_USER_BACKEND_SHMEM_MAP: > + ret =3D vhost_user_backend_handle_shmem_map(dev, ioc, &hdr, &pay= load, > + fd ? fd[0] : -1, &loca= l_err); > + break; > + case VHOST_USER_BACKEND_SHMEM_UNMAP: > + ret =3D vhost_user_backend_handle_shmem_unmap(dev, ioc, &hdr, &p= ayload, > + &local_err); > + break; > break; > default: > error_report("Received unexpected msg type: %d.", hdr.request); > diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c > index 85110bce37..47d0ddb820 100644 > --- a/hw/virtio/virtio.c > +++ b/hw/virtio/virtio.c > @@ -3063,6 +3063,75 @@ int virtio_save(VirtIODevice *vdev, QEMUFile *f) > return vmstate_save_state(f, &vmstate_virtio, vdev, NULL); > } > =20 > +VirtSharedMemory *virtio_new_shmem_region(VirtIODevice *vdev) > +{ > + ++vdev->n_shmem_regions; > + vdev->shmem_list =3D g_renew(VirtSharedMemory, vdev->shmem_list, > + vdev->n_shmem_regions); > + vdev->shmem_list[vdev->n_shmem_regions - 1].mr =3D g_new0(MemoryRegi= on, 1); > + QTAILQ_INIT(&vdev->shmem_list[vdev->n_shmem_regions - 1].mmaps); QTAILQ cannot be used inside a struct that is reallocated using g_renew() because a dangling tql_prev pointer will be left after reallocation. From QTAILQ_INIT(): (head)->tqh_circ.tql_prev =3D &(head)->tqh_circ; <--- not realloc-safe Instead of using g_renew() on an array, consider using a list from "qemu/queue.h". Lookup by shmid becomes O(n) instead of O(1), but it doesn't matter in practice since existing devices have a small number of VIRTIO Shared Memory Regions. > + return &vdev->shmem_list[vdev->n_shmem_regions - 1]; > +} > + > +void virtio_add_shmem_map(VirtSharedMemory *shmem, const char *shm_name, > + hwaddr shm_offset, hwaddr fd_offset, uint64_t = size, > + int fd, Error **errp) > +{ > + MappedMemoryRegion *mmap; > + fd =3D dup(fd); > + if (fd < 0) { > + error_setg_errno(errp, errno, "Failed to duplicate fd"); > + return; > + } > + > + if (shm_offset + size > shmem->mr->size) { > + error_setg(errp, "Memory exceeds the shared memory boundaries"); > + return; fd is leaked here. > + } > + > + mmap =3D g_new0(MappedMemoryRegion, 1); > + mmap->mem =3D g_new0(MemoryRegion, 1); > + mmap->offset =3D shm_offset; > + if (!memory_region_init_ram_from_fd(mmap->mem, > + OBJECT(shmem->mr), > + shm_name, size, RAM_SHARED, > + fd, fd_offset, errp)) { > + error_setg(errp, "Failed to mmap region %s", shm_name); > + close(fd); > + g_free(mmap->mem); > + g_free(mmap); > + return; > + } > + memory_region_add_subregion(shmem->mr, shm_offset, mmap->mem); > + > + QTAILQ_INSERT_TAIL(&shmem->mmaps, mmap, link); > +} > + > +MappedMemoryRegion *virtio_find_shmem_map(VirtSharedMemory *shmem, > + hwaddr offset, uint64_t size) > +{ > + MappedMemoryRegion *mmap; > + QTAILQ_FOREACH(mmap, &shmem->mmaps, link) { > + if (mmap->offset =3D=3D offset && mmap->mem->size =3D=3D size) { > + return mmap; > + } > + } > + return NULL; > +} > + > +void virtio_del_shmem_map(VirtSharedMemory *shmem, hwaddr offset, > + uint64_t size) > +{ > + MappedMemoryRegion *mmap =3D virtio_find_shmem_map(shmem, offset, si= ze); > + if (mmap =3D=3D NULL) { > + return; > + } > + > + object_unparent(OBJECT(mmap->mem)); > + QTAILQ_REMOVE(&shmem->mmaps, mmap, link); > + g_free(mmap); > +} > + > /* A wrapper for use as a VMState .put function */ > static int virtio_device_put(QEMUFile *f, void *opaque, size_t size, > const VMStateField *field, JSONWriter *vmd= esc) > @@ -3492,6 +3561,8 @@ void virtio_init(VirtIODevice *vdev, uint16_t devic= e_id, size_t config_size) > virtio_vmstate_change, vdev); > vdev->device_endian =3D virtio_default_endian(); > vdev->use_guest_notifier_mask =3D true; > + vdev->shmem_list =3D NULL; > + vdev->n_shmem_regions =3D 0; > } > =20 > /* > @@ -4005,11 +4076,21 @@ static void virtio_device_free_virtqueues(VirtIOD= evice *vdev) > static void virtio_device_instance_finalize(Object *obj) > { > VirtIODevice *vdev =3D VIRTIO_DEVICE(obj); > + VirtSharedMemory *shmem =3D NULL; > + int i; > =20 > virtio_device_free_virtqueues(vdev); > =20 > g_free(vdev->config); > g_free(vdev->vector_queues); > + for (i =3D 0; i< vdev->n_shmem_regions; i++) { > + shmem =3D &vdev->shmem_list[i]; > + while (!QTAILQ_EMPTY(&shmem->mmaps)) { > + MappedMemoryRegion *mmap_reg =3D QTAILQ_FIRST(&shmem->mmaps); > + QTAILQ_REMOVE(&shmem->mmaps, mmap_reg, link); > + g_free(mmap_reg); Is it possible to reuse virtio_del_shmem_map() to avoid code duplication and inconsistencies? while (!QTAILQ_EMPTY(&shmem->mmaps)) { MappedMemoryRegion *mmap_reg =3D QTAILQ_FIRST(&shmem->mmaps); virtio_del_shmem_map(shmem, mmap_reg->offset, mmap_reg->mem->size); } > + } > + } Missing g_free(vdev->shmem_list). > } > =20 > static const Property virtio_properties[] =3D { > diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h > index 6386910280..a778547c79 100644 > --- a/include/hw/virtio/virtio.h > +++ b/include/hw/virtio/virtio.h > @@ -98,6 +98,21 @@ enum virtio_device_endian { > VIRTIO_DEVICE_ENDIAN_BIG, > }; > =20 > +struct MappedMemoryRegion { > + MemoryRegion *mem; > + hwaddr offset; > + QTAILQ_ENTRY(MappedMemoryRegion) link; > +}; > + > +typedef struct MappedMemoryRegion MappedMemoryRegion; > + > +struct VirtSharedMemory { > + MemoryRegion *mr; > + QTAILQ_HEAD(, MappedMemoryRegion) mmaps; > +}; > + > +typedef struct VirtSharedMemory VirtSharedMemory; > + > /** > * struct VirtIODevice - common VirtIO structure > * @name: name of the device > @@ -167,6 +182,9 @@ struct VirtIODevice > */ > EventNotifier config_notifier; > bool device_iotlb_enabled; > + /* Shared memory region for vhost-user mappings. */ This is core VIRTIO code and Shared Memory Regions are a VIRTIO concept. It is possible that built-in (non-vhost) devices might also add their shared memory regions with virtio_new_shmem_region(), so let's not talk about vhost-user specifically. > + VirtSharedMemory *shmem_list; > + int n_shmem_regions; > }; > =20 > struct VirtioDeviceClass { > @@ -289,6 +307,15 @@ void virtio_notify(VirtIODevice *vdev, VirtQueue *vq= ); > =20 > int virtio_save(VirtIODevice *vdev, QEMUFile *f); > =20 > +VirtSharedMemory *virtio_new_shmem_region(VirtIODevice *vdev); > +void virtio_add_shmem_map(VirtSharedMemory *shmem, const char *shm_name, > + hwaddr shm_offset, hwaddr fd_offset, uint64_t = size, > + int fd, Error **errp); > +MappedMemoryRegion *virtio_find_shmem_map(VirtSharedMemory *shmem, hwadd= r offset, > + uint64_t size); > +void virtio_del_shmem_map(VirtSharedMemory *shmem, hwaddr offset, > + uint64_t size); > + > extern const VMStateInfo virtio_vmstate_info; > =20 > #define VMSTATE_VIRTIO_DEVICE \ > diff --git a/subprojects/libvhost-user/libvhost-user.c b/subprojects/libv= host-user/libvhost-user.c > index 9c630c2170..034cbfdc3c 100644 > --- a/subprojects/libvhost-user/libvhost-user.c > +++ b/subprojects/libvhost-user/libvhost-user.c > @@ -1592,6 +1592,76 @@ vu_rm_shared_object(VuDev *dev, unsigned char uuid= [UUID_LEN]) > return vu_send_message(dev, &msg); > } > =20 > +bool > +vu_shmem_map(VuDev *dev, uint8_t shmid, uint64_t fd_offset, > + uint64_t shm_offset, uint64_t len, uint64_t flags, int fd) > +{ > + VhostUserMsg vmsg =3D { > + .request =3D VHOST_USER_BACKEND_SHMEM_MAP, > + .size =3D sizeof(vmsg.payload.mmap), > + .flags =3D VHOST_USER_VERSION, > + .payload.mmap =3D { > + .shmid =3D shmid, > + .fd_offset =3D fd_offset, > + .shm_offset =3D shm_offset, > + .len =3D len, > + .flags =3D flags, > + }, > + .fd_num =3D 1, > + .fds[0] =3D fd, > + }; > + > + if (!vu_has_protocol_feature(dev, VHOST_USER_PROTOCOL_F_SHMEM)) { > + return false; > + } > + > + if (vu_has_protocol_feature(dev, VHOST_USER_PROTOCOL_F_REPLY_ACK)) { > + vmsg.flags |=3D VHOST_USER_NEED_REPLY_MASK; > + } Setting this flag is inconsistent with vhost_user_backend_handle_shmem_map() and vhost_user_backend_handle_shmem_unmap(). They call vhost_user_send_resp() explicitly instead of relying on backend_read() to send the return value when VHOST_USER_NEED_REPLY_MASK is set. This inconsistency means that a successful return message will be sent twice when VHOST_USER_NEED_REPLY_MASK is set. Either these new vhost-user messages could be specified with a mandatory reply payload or the patch could be updated to avoid the explicit vhost_user_send_resp() calls. I think the latter is more commonly used by other vhost-user messages, so it's probably best to do it the same way. > + > + pthread_mutex_lock(&dev->backend_mutex); > + if (!vu_message_write(dev, dev->backend_fd, &vmsg)) { > + pthread_mutex_unlock(&dev->backend_mutex); > + return false; > + } > + > + /* Also unlocks the backend_mutex */ > + return vu_process_message_reply(dev, &vmsg); > +} > + > +bool > +vu_shmem_unmap(VuDev *dev, uint8_t shmid, uint64_t shm_offset, uint64_t = len) > +{ > + VhostUserMsg vmsg =3D { > + .request =3D VHOST_USER_BACKEND_SHMEM_UNMAP, > + .size =3D sizeof(vmsg.payload.mmap), > + .flags =3D VHOST_USER_VERSION, > + .payload.mmap =3D { > + .shmid =3D shmid, > + .fd_offset =3D 0, > + .shm_offset =3D shm_offset, > + .len =3D len, > + }, > + }; > + > + if (!vu_has_protocol_feature(dev, VHOST_USER_PROTOCOL_F_SHMEM)) { > + return false; > + } > + > + if (vu_has_protocol_feature(dev, VHOST_USER_PROTOCOL_F_REPLY_ACK)) { > + vmsg.flags |=3D VHOST_USER_NEED_REPLY_MASK; > + } > + > + pthread_mutex_lock(&dev->backend_mutex); > + if (!vu_message_write(dev, dev->backend_fd, &vmsg)) { > + pthread_mutex_unlock(&dev->backend_mutex); > + return false; > + } > + > + /* Also unlocks the backend_mutex */ > + return vu_process_message_reply(dev, &vmsg); > +} > + > static bool > vu_set_vring_call_exec(VuDev *dev, VhostUserMsg *vmsg) > { > diff --git a/subprojects/libvhost-user/libvhost-user.h b/subprojects/libv= host-user/libvhost-user.h > index 2ffc58c11b..e9adb836f0 100644 > --- a/subprojects/libvhost-user/libvhost-user.h > +++ b/subprojects/libvhost-user/libvhost-user.h > @@ -69,6 +69,8 @@ enum VhostUserProtocolFeature { > /* Feature 16 is reserved for VHOST_USER_PROTOCOL_F_STATUS. */ > /* Feature 17 reserved for VHOST_USER_PROTOCOL_F_XEN_MMAP. */ > VHOST_USER_PROTOCOL_F_SHARED_OBJECT =3D 18, > + /* Feature 19 is reserved for VHOST_USER_PROTOCOL_F_DEVICE_STATE */ > + VHOST_USER_PROTOCOL_F_SHMEM =3D 20, > VHOST_USER_PROTOCOL_F_MAX > }; > =20 > @@ -127,6 +129,8 @@ typedef enum VhostUserBackendRequest { > VHOST_USER_BACKEND_SHARED_OBJECT_ADD =3D 6, > VHOST_USER_BACKEND_SHARED_OBJECT_REMOVE =3D 7, > VHOST_USER_BACKEND_SHARED_OBJECT_LOOKUP =3D 8, > + VHOST_USER_BACKEND_SHMEM_MAP =3D 9, > + VHOST_USER_BACKEND_SHMEM_UNMAP =3D 10, > VHOST_USER_BACKEND_MAX > } VhostUserBackendRequest; > =20 > @@ -186,6 +190,24 @@ typedef struct VhostUserShared { > unsigned char uuid[UUID_LEN]; > } VhostUserShared; > =20 > +/* For the flags field of VhostUserMMap */ > +#define VHOST_USER_FLAG_MAP_R (1u << 0) > +#define VHOST_USER_FLAG_MAP_W (1u << 1) > + > +typedef struct { > + /* VIRTIO Shared Memory Region ID */ > + uint8_t shmid; > + uint8_t padding[7]; > + /* File offset */ > + uint64_t fd_offset; > + /* Offset within the VIRTIO Shared Memory Region */ > + uint64_t shm_offset; > + /* Size of the mapping */ > + uint64_t len; > + /* Flags for the mmap operation, from VHOST_USER_FLAG_* */ > + uint64_t flags; > +} VhostUserMMap; > + > #define VU_PACKED __attribute__((packed)) > =20 > typedef struct VhostUserMsg { > @@ -210,6 +232,7 @@ typedef struct VhostUserMsg { > VhostUserVringArea area; > VhostUserInflight inflight; > VhostUserShared object; > + VhostUserMMap mmap; > } payload; > =20 > int fds[VHOST_MEMORY_BASELINE_NREGIONS]; > @@ -593,6 +616,38 @@ bool vu_add_shared_object(VuDev *dev, unsigned char = uuid[UUID_LEN]); > */ > bool vu_rm_shared_object(VuDev *dev, unsigned char uuid[UUID_LEN]); > =20 > +/** > + * vu_shmem_map: > + * @dev: a VuDev context > + * @shmid: VIRTIO Shared Memory Region ID > + * @fd_offset: File offset > + * @shm_offset: Offset within the VIRTIO Shared Memory Region > + * @len: Size of the mapping > + * @flags: Flags for the mmap operation > + * @fd: A file descriptor > + * > + * Advertises a new mapping to be made in a given VIRTIO Shared Memory R= egion. > + * > + * Returns: TRUE on success, FALSE on failure. > + */ > +bool vu_shmem_map(VuDev *dev, uint8_t shmid, uint64_t fd_offset, > + uint64_t shm_offset, uint64_t len, uint64_t flags, int= fd); > + > +/** > + * vu_shmem_unmap: > + * @dev: a VuDev context > + * @shmid: VIRTIO Shared Memory Region ID > + * @fd_offset: File offset > + * @len: Size of the mapping > + * > + * The front-end un-mmaps a given range in the VIRTIO Shared Memory Regi= on > + * with the requested `shmid`. > + * > + * Returns: TRUE on success, FALSE on failure. > + */ > +bool vu_shmem_unmap(VuDev *dev, uint8_t shmid, uint64_t shm_offset, > + uint64_t len); > + > /** > * vu_queue_set_notification: > * @dev: a VuDev context > --=20 > 2.48.1 >=20 --n+QqPn/txEljMN+E Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAme0LAkACgkQnKSrs4Gr c8j8gAgAsXRlBcJclwaomWBAslIUkrBKlok6XzTIuZQRb1BFIemxZniD6fs1Dlhh dnIkuPXNiT4/dChlmAtl3fM7LlKajRMgULyVLSXPzqiRq8Q+7ognvdrdug8p4rzj WyJaYkrlUErbjyddzjJ0/D/VpZt8aoTmyoGHWkyhuj6TdaRpKbeqby+iCGwydHh3 u2w8W8OlTC0oWV81fSH8tX4T60qRTjfvb19ZtVnebvJF0GhQFmjmfv/Npk0/vfZp kfQ88xDaSGdwEbnyqp0mmuay0FY6mWBJRghr/PrUI2HNo5gUordYLug1hTYZl1Gb GVlsBq/cn9hG1fqeYY6CIl6k8CrVhQ== =99Tq -----END PGP SIGNATURE----- --n+QqPn/txEljMN+E--