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[212.216.181.31]) by smtp.gmail.com with ESMTPSA id z14sm22287121wrl.60.2019.11.18.03.50.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 18 Nov 2019 03:50:26 -0800 (PST) Date: Mon, 18 Nov 2019 12:50:24 +0100 From: Stefano Garzarella To: "David S. Miller" Cc: netdev@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Jason Wang , kvm , "Michael S. Tsirkin" , Stefan Hajnoczi Subject: Re: [PATCH net-next v5 4/5] vhost/vsock: split packets to send using multiple buffers Message-ID: References: <20190730154334.237789-1-sgarzare@redhat.com> <20190730154334.237789-5-sgarzare@redhat.com> MIME-Version: 1.0 In-Reply-To: <20190730154334.237789-5-sgarzare@redhat.com> X-MC-Unique: r34MXys-NEunMwW_tZureQ-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Dave, talking to Michael, we realized that this patch merged upstream (commit 6dbd3e66e7785a2f055bf84d98de9b8fd31ff3f5) solves an issue in the device emulation in the vhost-vsock module, because the emulation did not meet the specification, assuming that the buffer in the RX virtqueue was always 4 KB, without checking the actual size. We think it's better to apply this patch in -stable. What do you think? Thanks, Stefano On Tue, Jul 30, 2019 at 5:44 PM Stefano Garzarella wr= ote: > > If the packets to sent to the guest are bigger than the buffer > available, we can split them, using multiple buffers and fixing > the length in the packet header. > This is safe since virtio-vsock supports only stream sockets. > > Signed-off-by: Stefano Garzarella > Reviewed-by: Stefan Hajnoczi > Acked-by: Michael S. Tsirkin > --- > drivers/vhost/vsock.c | 66 ++++++++++++++++++------- > net/vmw_vsock/virtio_transport_common.c | 15 ++++-- > 2 files changed, 60 insertions(+), 21 deletions(-) > > diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c > index 6c8390a2af52..9f57736fe15e 100644 > --- a/drivers/vhost/vsock.c > +++ b/drivers/vhost/vsock.c > @@ -102,7 +102,7 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock= , > struct iov_iter iov_iter; > unsigned out, in; > size_t nbytes; > - size_t len; > + size_t iov_len, payload_len; > int head; > > spin_lock_bh(&vsock->send_pkt_list_lock); > @@ -147,8 +147,24 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsoc= k, > break; > } > > - len =3D iov_length(&vq->iov[out], in); > - iov_iter_init(&iov_iter, READ, &vq->iov[out], in, len); > + iov_len =3D iov_length(&vq->iov[out], in); > + if (iov_len < sizeof(pkt->hdr)) { > + virtio_transport_free_pkt(pkt); > + vq_err(vq, "Buffer len [%zu] too small\n", iov_le= n); > + break; > + } > + > + iov_iter_init(&iov_iter, READ, &vq->iov[out], in, iov_len= ); > + payload_len =3D pkt->len - pkt->off; > + > + /* If the packet is greater than the space available in t= he > + * buffer, we split it using multiple buffers. > + */ > + if (payload_len > iov_len - sizeof(pkt->hdr)) > + payload_len =3D iov_len - sizeof(pkt->hdr); > + > + /* Set the correct length in the header */ > + pkt->hdr.len =3D cpu_to_le32(payload_len); > > nbytes =3D copy_to_iter(&pkt->hdr, sizeof(pkt->hdr), &iov= _iter); > if (nbytes !=3D sizeof(pkt->hdr)) { > @@ -157,33 +173,47 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vso= ck, > break; > } > > - nbytes =3D copy_to_iter(pkt->buf, pkt->len, &iov_iter); > - if (nbytes !=3D pkt->len) { > + nbytes =3D copy_to_iter(pkt->buf + pkt->off, payload_len, > + &iov_iter); > + if (nbytes !=3D payload_len) { > virtio_transport_free_pkt(pkt); > vq_err(vq, "Faulted on copying pkt buf\n"); > break; > } > > - vhost_add_used(vq, head, sizeof(pkt->hdr) + pkt->len); > + vhost_add_used(vq, head, sizeof(pkt->hdr) + payload_len); > added =3D true; > > - if (pkt->reply) { > - int val; > - > - val =3D atomic_dec_return(&vsock->queued_replies)= ; > - > - /* Do we have resources to resume tx processing? = */ > - if (val + 1 =3D=3D tx_vq->num) > - restart_tx =3D true; > - } > - > /* Deliver to monitoring devices all correctly transmitte= d > * packets. > */ > virtio_transport_deliver_tap_pkt(pkt); > > - total_len +=3D pkt->len; > - virtio_transport_free_pkt(pkt); > + pkt->off +=3D payload_len; > + total_len +=3D payload_len; > + > + /* If we didn't send all the payload we can requeue the p= acket > + * to send it with the next available buffer. > + */ > + if (pkt->off < pkt->len) { > + spin_lock_bh(&vsock->send_pkt_list_lock); > + list_add(&pkt->list, &vsock->send_pkt_list); > + spin_unlock_bh(&vsock->send_pkt_list_lock); > + } else { > + if (pkt->reply) { > + int val; > + > + val =3D atomic_dec_return(&vsock->queued_= replies); > + > + /* Do we have resources to resume tx > + * processing? > + */ > + if (val + 1 =3D=3D tx_vq->num) > + restart_tx =3D true; > + } > + > + virtio_transport_free_pkt(pkt); > + } > } while(likely(!vhost_exceeds_weight(vq, ++pkts, total_len))); > if (added) > vhost_signal(&vsock->dev, vq); > diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virt= io_transport_common.c > index 34a2b42313b7..56fab3f03d0e 100644 > --- a/net/vmw_vsock/virtio_transport_common.c > +++ b/net/vmw_vsock/virtio_transport_common.c > @@ -97,8 +97,17 @@ static struct sk_buff *virtio_transport_build_skb(void= *opaque) > struct virtio_vsock_pkt *pkt =3D opaque; > struct af_vsockmon_hdr *hdr; > struct sk_buff *skb; > + size_t payload_len; > + void *payload_buf; > > - skb =3D alloc_skb(sizeof(*hdr) + sizeof(pkt->hdr) + pkt->len, > + /* A packet could be split to fit the RX buffer, so we can retrie= ve > + * the payload length from the header and the buffer pointer taki= ng > + * care of the offset in the original packet. > + */ > + payload_len =3D le32_to_cpu(pkt->hdr.len); > + payload_buf =3D pkt->buf + pkt->off; > + > + skb =3D alloc_skb(sizeof(*hdr) + sizeof(pkt->hdr) + payload_len, > GFP_ATOMIC); > if (!skb) > return NULL; > @@ -138,8 +147,8 @@ static struct sk_buff *virtio_transport_build_skb(voi= d *opaque) > > skb_put_data(skb, &pkt->hdr, sizeof(pkt->hdr)); > > - if (pkt->len) { > - skb_put_data(skb, pkt->buf, pkt->len); > + if (payload_len) { > + skb_put_data(skb, payload_buf, payload_len); > } > > return skb; > -- > 2.20.1 >