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Violators will be prosecuted for from ; Mon, 18 Sep 2017 21:37:34 -0600 Date: Tue, 19 Sep 2017 11:37:30 +0800 From: Dong Jia Shi References: <20170913115029.47626-1-pasic@linux.vnet.ibm.com> <20170913115029.47626-4-pasic@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170913115029.47626-4-pasic@linux.vnet.ibm.com> Message-Id: <20170919033730.GD5274@bjsdjshi@linux.vnet.ibm.com> Subject: Re: [Qemu-devel] [PATCH v2 3/4] virtio-ccw: use ccw data stream List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Halil Pasic Cc: Cornelia Huck , Dong Jia Shi , Pierre Morel , qemu-devel@nongnu.org * Halil Pasic [2017-09-13 13:50:28 +0200]: > Replace direct access which implicitly assumes no IDA > or MIDA with the new ccw data stream interface which should > cope with these transparently in the future. > > Signed-off-by: Halil Pasic > > --- > > v1 --> v2: > Removed todo comments on possible errno change as with > https://lists.nongnu.org/archive/html/qemu-devel/2017-09/msg02441.html > applied it does not matter any more. > > Error handling: At the moment we ignore errors reported > by stream ops to keep the change minimal. An add-on > patch improving on this is to be expected later. Add a TODO somewhere around the code as a reminder? > --- > hw/s390x/virtio-ccw.c | 156 +++++++++++++++----------------------------------- > 1 file changed, 46 insertions(+), 110 deletions(-) > > diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c > index b1976fdd19..a9baf6f7ab 100644 > --- a/hw/s390x/virtio-ccw.c > +++ b/hw/s390x/virtio-ccw.c [...] > @@ -394,11 +362,8 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw) > } else { > VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev); > > - features.index = address_space_ldub(&address_space_memory, > - ccw.cda > - + sizeof(features.features), > - MEMTXATTRS_UNSPECIFIED, > - NULL); > + ccw_dstream_advance(&sch->cds, sizeof(features.features)); How about: ccw_dstream_advance(&sch->cds, offsetof(VirtioFeatDesc, index)); > + ccw_dstream_read(&sch->cds, features.index); > if (features.index == 0) { > if (dev->revision >= 1) { > /* Don't offer legacy features for modern devices. */ > @@ -417,9 +382,9 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw) > /* Return zeroes if the guest supports more feature bits. */ > features.features = 0; > } > - address_space_stl_le(&address_space_memory, ccw.cda, > - features.features, MEMTXATTRS_UNSPECIFIED, > - NULL); > + ccw_dstream_rewind(&sch->cds); > + cpu_to_le32s(&features.features); > + ccw_dstream_write(&sch->cds, features.features); > sch->curr_status.scsw.count = ccw.count - sizeof(features); How about: sch->curr_status.scsw.count = ccw_dstream_residual_count(&sch->cds); This also applies to other places. > ret = 0; > } [...] > @@ -501,21 +459,13 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw) > } > } > len = MIN(ccw.count, vdev->config_len); > - hw_len = len; > if (!ccw.cda) { > ret = -EFAULT; > } else { > - config = cpu_physical_memory_map(ccw.cda, &hw_len, 0); > - if (!config) { > - ret = -EFAULT; > - } else { > - len = hw_len; > - /* XXX config space endianness */ > - memcpy(vdev->config, config, len); > - cpu_physical_memory_unmap(config, hw_len, 0, hw_len); > + ret = ccw_dstream_read_buf(&sch->cds, vdev->config, len); > + if (!ret) { Add a TODO here, and: if (ccw_dstream_read_buf(&sch->cds, vdev->config, len)) { ret = -EFAULT; } else { .... } > virtio_bus_set_vdev_config(&dev->bus, vdev->config); > sch->curr_status.scsw.count = ccw.count - len; > - ret = 0; > } > } > break; [...] > @@ -714,13 +654,9 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw) > ret = -EFAULT; > break; > } > - revinfo.revision = > - address_space_lduw_be(&address_space_memory, ccw.cda, > - MEMTXATTRS_UNSPECIFIED, NULL); > - revinfo.length = > - address_space_lduw_be(&address_space_memory, > - ccw.cda + sizeof(revinfo.revision), > - MEMTXATTRS_UNSPECIFIED, NULL); > + ccw_dstream_read_buf(&sch->cds, &revinfo, 4); ^ A magic number? O:) > + be16_to_cpus(&revinfo.revision); > + be16_to_cpus(&revinfo.length); > if (ccw.count < len + revinfo.length || > (check_len && ccw.count > len + revinfo.length)) { > ret = -EINVAL; > -- > 2.13.5 > Otherwise, looks good. -- Dong Jia Shi