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Tue, 18 Feb 2025 13:29:20 +0000 (UTC) Received: from localhost (unknown [10.2.16.111]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 339B11800352; Tue, 18 Feb 2025 13:29:17 +0000 (UTC) Date: Tue, 18 Feb 2025 21:25:16 +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 7/9] vhost-user-devive: Add shmem BAR Message-ID: <20250218132516.GA28047@fedora> References: <20250217164012.246727-1-aesteve@redhat.com> <20250217164012.246727-8-aesteve@redhat.com> <20250218104116.GK10767@fedora> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="MmHLaugt0pq71LVJ" Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 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: -24 X-Spam_score: -2.5 X-Spam_bar: -- X-Spam_report: (-2.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.423, 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_H5=0.001, RCVD_IN_MSPIKE_WL=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 --MmHLaugt0pq71LVJ Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Feb 18, 2025 at 11:55:33AM +0100, Albert Esteve wrote: > On Tue, Feb 18, 2025 at 11:41=E2=80=AFAM Stefan Hajnoczi wrote: > > > > On Mon, Feb 17, 2025 at 05:40:10PM +0100, Albert Esteve wrote: > > > Add a shmem BAR block in the vhost-user-device, > > > which files can be directly mapped into. > > > > > > The number, shmid, and size of the VIRTIO Shared > > > Memory subregions is retrieved through a > > > get_shmem_config message sent by the > > > vhost-user-base module on the realize step, > > > after virtio_init(). > > > > > > By default, if VHOST_USER_PROTOCOL_F_SHMEM > > > feature is not supported by the backend, > > > there is no cache. > > > > > > Signed-off-by: Albert Esteve > > > --- > > > hw/virtio/vhost-user-base.c | 47 +++++++++++++++++++++++++++++= -- > > > hw/virtio/vhost-user-device-pci.c | 36 +++++++++++++++++++++-- > > > 2 files changed, 78 insertions(+), 5 deletions(-) > > > > > > diff --git a/hw/virtio/vhost-user-base.c b/hw/virtio/vhost-user-base.c > > > index 2bc3423326..8d4bca98a8 100644 > > > --- a/hw/virtio/vhost-user-base.c > > > +++ b/hw/virtio/vhost-user-base.c > > > @@ -16,6 +16,7 @@ > > > #include "hw/virtio/virtio-bus.h" > > > #include "hw/virtio/vhost-user-base.h" > > > #include "qemu/error-report.h" > > > +#include "migration/blocker.h" > > > > > > static void vub_start(VirtIODevice *vdev) > > > { > > > @@ -271,7 +272,8 @@ static void vub_device_realize(DeviceState *dev, = Error **errp) > > > { > > > VirtIODevice *vdev =3D VIRTIO_DEVICE(dev); > > > VHostUserBase *vub =3D VHOST_USER_BASE(dev); > > > - int ret; > > > + uint64_t memory_sizes[VIRTIO_MAX_SHMEM_REGIONS]; > > > + int i, ret, nregions; > > > > > > if (!vub->chardev.chr) { > > > error_setg(errp, "vhost-user-base: missing chardev"); > > > @@ -314,7 +316,7 @@ static void vub_device_realize(DeviceState *dev, = Error **errp) > > > > > > /* Allocate queues */ > > > vub->vqs =3D g_ptr_array_sized_new(vub->num_vqs); > > > - for (int i =3D 0; i < vub->num_vqs; i++) { > > > + for (i =3D 0; i < vub->num_vqs; i++) { > > > g_ptr_array_add(vub->vqs, > > > virtio_add_queue(vdev, vub->vq_size, > > > vub_handle_output)); > > > @@ -328,11 +330,50 @@ static void vub_device_realize(DeviceState *dev= , Error **errp) > > > VHOST_BACKEND_TYPE_USER, 0, errp); > > > > > > if (ret < 0) { > > > - do_vhost_user_cleanup(vdev, vub); > > > + goto err; > > > + } > > > + > > > + ret =3D vub->vhost_dev.vhost_ops->vhost_get_shmem_config(&vub->v= host_dev, > > > + &nregions, > > > + memory_si= zes, > > > + errp); > > > + > > > + if (ret < 0) { > > > + goto err; > > > + } > > > + > > > + for (i =3D 0; i < nregions; i++) { > > > + if (memory_sizes[i]) { > > > + if (vub->vhost_dev.migration_blocker =3D=3D NULL) { > > > + error_setg(&vub->vhost_dev.migration_blocker, > > > + "Migration disabled: devices with VIRTIO Shar= ed Memory " > > > + "Regions do not support migration yet."); > > > + ret =3D migrate_add_blocker_normal( > > > + &vub->vhost_dev.migration_blocker, > > > + errp); > > > + > > > + if (ret < 0) { > > > + goto err; > > > + } > > > + } > > > + > > > + if (memory_sizes[i] % qemu_real_host_page_size() !=3D 0)= { > > > + error_setg(errp, "Shared memory %d size must be a po= wer of 2 " > > > + "no smaller than the page size", i); > > > + goto err; > > > + } > > > + > > > + memory_region_init(virtio_new_shmem_region(vdev)->mr, > > > > Does this code support non-contiguous shmids? For example, if a device > > has two Shared Memory Regions defined in its spec but the first one is > > optional, then the device might have memory_sizes[0] =3D=3D 0 and > > memory_sizes[1] > 0. In that case the Shared Memory Region must have > > shmid 1 and not shmid 0. >=20 > Yes, it does. That is guarded by ` if (memory_sizes[i]) {`, which only > initializes the region if memory_sizes[i] > 0. The main downsize of > that, is that it requires to send as many `memory_sizes` elements as > the highest shmid for the device. But as it is, it is supported by > this code. shmids are not preserved when there are gaps: for (i =3D 0; i < vdev->n_shmem_regions; i++) { memory_region_add_subregion(&dev->shmembar, offset, mr); virtio_pci_add_shm_cap(vpci_dev, VIRTIO_DEVICE_PCI_SHMEM_BAR, offset, mr->size, i); ^ vdev->n_shmem_regions is incremented by virtio_new_shmem_region(). virtio_new_shmem_region() is only called on non-empty Shared Memory Regions. In the example I gave with empty shmid 0 and non-empty shmid 1 I think we end up with vdev->n_shmem_regions =3D=3D 1. shmdid 1 is exposed to the guest with shmid 0. Have I missed something? > > > > > + OBJECT(vdev), "vub-shm-" + i, > > > + memory_sizes[i]); > > > + } > > > } > > > > > > qemu_chr_fe_set_handlers(&vub->chardev, NULL, NULL, vub_event, N= ULL, > > > dev, NULL, true); > > > + return; > > > +err: > > > + do_vhost_user_cleanup(vdev, vub); > > > } > > > > > > static void vub_device_unrealize(DeviceState *dev) > > > diff --git a/hw/virtio/vhost-user-device-pci.c b/hw/virtio/vhost-user= -device-pci.c > > > index efaf55d3dd..f215cae925 100644 > > > --- a/hw/virtio/vhost-user-device-pci.c > > > +++ b/hw/virtio/vhost-user-device-pci.c > > > @@ -8,14 +8,18 @@ > > > */ > > > > > > #include "qemu/osdep.h" > > > +#include "qapi/error.h" > > > #include "hw/qdev-properties.h" > > > #include "hw/virtio/vhost-user-base.h" > > > #include "hw/virtio/virtio-pci.h" > > > > > > +#define VIRTIO_DEVICE_PCI_SHMEM_BAR 2 > > > + > > > struct VHostUserDevicePCI { > > > VirtIOPCIProxy parent_obj; > > > > > > VHostUserBase vub; > > > + MemoryRegion shmembar; > > > }; > > > > > > #define TYPE_VHOST_USER_DEVICE_PCI "vhost-user-device-pci-base" > > > @@ -25,10 +29,38 @@ OBJECT_DECLARE_SIMPLE_TYPE(VHostUserDevicePCI, VH= OST_USER_DEVICE_PCI) > > > static void vhost_user_device_pci_realize(VirtIOPCIProxy *vpci_dev, = Error **errp) > > > { > > > VHostUserDevicePCI *dev =3D VHOST_USER_DEVICE_PCI(vpci_dev); > > > - DeviceState *vdev =3D DEVICE(&dev->vub); > > > + DeviceState *dev_state =3D DEVICE(&dev->vub); > > > + VirtIODevice *vdev =3D VIRTIO_DEVICE(dev_state); > > > + MemoryRegion *mr; > > > + uint64_t offset =3D 0, shmem_size =3D 0; > > > + int i; > > > > > > vpci_dev->nvectors =3D 1; > > > - qdev_realize(vdev, BUS(&vpci_dev->bus), errp); > > > + qdev_realize(dev_state, BUS(&vpci_dev->bus), errp); > > > + > > > + for (i =3D 0; i < vdev->n_shmem_regions; i++) { > > > + mr =3D vdev->shmem_list[i].mr; > > > + if (mr->size > UINT64_MAX - shmem_size) { > > > + error_setg(errp, "Total shared memory required overflow"= ); > > > + return; > > > + } > > > + shmem_size =3D shmem_size + mr->size; > > > + } > > > + if (shmem_size) { > > > + memory_region_init(&dev->shmembar, OBJECT(vpci_dev), > > > + "vhost-device-pci-shmembar", shmem_size); > > > + for (i =3D 0; i < vdev->n_shmem_regions; i++) { > > > + memory_region_add_subregion(&dev->shmembar, offset, mr); > > > + virtio_pci_add_shm_cap(vpci_dev, VIRTIO_DEVICE_PCI_SHMEM= _BAR, > > > + offset, mr->size, i); > > > + offset =3D offset + mr->size; > > > + } > > > + pci_register_bar(&vpci_dev->pci_dev, VIRTIO_DEVICE_PCI_SHMEM= _BAR, > > > + PCI_BASE_ADDRESS_SPACE_MEMORY | > > > + PCI_BASE_ADDRESS_MEM_PREFETCH | > > > + PCI_BASE_ADDRESS_MEM_TYPE_64, > > > + &dev->shmembar); > > > + } > > > } > > > > > > static void vhost_user_device_pci_class_init(ObjectClass *klass, voi= d *data) > > > -- > > > 2.48.1 > > > >=20 --MmHLaugt0pq71LVJ Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAme0ijwACgkQnKSrs4Gr c8hIYgf/ReXKr50DystLpeb9xil2dFbTru61Cvph2cgEVZJtIDeUYAsGrxDt9XwU S7uIhy3L1RSblRp6vbBq2FOSS1pTPDmImjXI8s7ueTqv2RZlsoCAJy4Cp/SgnHx/ JAjbo8SwDqkXiNBVlzMiFYE3YQUwd7TmFIblfCIlleteDzOByB8ILCFLKK/sCqsq p9BJWBIX1gtgrUow/bb76ggzzbWlgc6LT1JMnfoaY9+tpzMDpzoQSidDbfXzRWSy HXHkiSR3iNnjT0RlNV64vRR36giYhTEpesrb75CfYyJDNuPFmPa/Ph8ucCxZrTZ7 HT2ybRg2MMj4To5Sr23ua0HXXjKZqA== =0+25 -----END PGP SIGNATURE----- --MmHLaugt0pq71LVJ--