On 16/01/18 10:10, Auger Eric wrote:
> Hi,
>
> On 17/11/17 19:52, Jean-Philippe Brucker wrote:
>> The event queue offers a way for the device to report access faults from
>> devices.
> end points?
Yes
[...]
>> +static void viommu_event_handler(struct virtqueue *vq)
>> +{
>> + int ret;
>> + unsigned int len;
>> + struct scatterlist sg[1];
>> + struct viommu_event *evt;
>> + struct viommu_dev *viommu = vq->vdev->priv;
>> +
>> + while ((evt = virtqueue_get_buf(vq, &len)) != NULL) {
>> + if (len > sizeof(*evt)) {
>> + dev_err(viommu->dev,
>> + "invalid event buffer (len %u != %zu)\n",
>> + len, sizeof(*evt));
>> + } else if (!(evt->head & VIOMMU_FAULT_RESV_MASK)) {
>> + viommu_fault_handler(viommu, &evt->fault);
>> + }
>> +
>> + sg_init_one(sg, evt, sizeof(*evt));
> in case of above error case, ie. len > sizeof(*evt), is it safe to push
> evt again?
I think it is, len is just what the device reports as written. The above
error would be a device bug, very unlikely and not worth a special
treatment (freeing the buffer), maybe not even worth the dev_err()
actually.
>> + ret = virtqueue_add_inbuf(vq, sg, 1, evt, GFP_ATOMIC);
>> + if (ret)
>> + dev_err(viommu->dev, "could not add event buffer\n");
>> + }
>> +
>> + if (!virtqueue_kick(vq))
>> + dev_err(viommu->dev, "kick failed\n");
>> +}
>> +
>> /* IOMMU API */
>>
>> static bool viommu_capable(enum iommu_cap cap)
>> @@ -938,19 +1018,44 @@ static struct iommu_ops viommu_ops = {
>> .put_resv_regions = viommu_put_resv_regions,
>> };
>>
>> -static int viommu_init_vq(struct viommu_dev *viommu)
>> +static int viommu_init_vqs(struct viommu_dev *viommu)
>> {
>> struct virtio_device *vdev = dev_to_virtio(viommu->dev);
>> - const char *name = "request";
>> - void *ret;
>> + const char *names[] = { "request", "event" };
>> + vq_callback_t *callbacks[] = {
>> + NULL, /* No async requests */
>> + viommu_event_handler,
>> + };
>> +
>> + return virtio_find_vqs(vdev, VIOMMU_NUM_VQS, viommu->vqs, callbacks,
>> + names, NULL);
>> +}
>>
>> - ret = virtio_find_single_vq(vdev, NULL, name);
>> - if (IS_ERR(ret)) {
>> - dev_err(viommu->dev, "cannot find VQ\n");
>> - return PTR_ERR(ret);
>> +static int viommu_fill_evtq(struct viommu_dev *viommu)
>> +{
>> + int i, ret;
>> + struct scatterlist sg[1];
>> + struct viommu_event *evts;
>> + struct virtqueue *vq = viommu->vqs[VIOMMU_EVENT_VQ];
>> + size_t nr_evts = min_t(size_t, PAGE_SIZE / sizeof(struct viommu_event),
>> + viommu->vqs[VIOMMU_EVENT_VQ]->num_free);
>> +
>> + evts = devm_kmalloc_array(viommu->dev, nr_evts, sizeof(*evts),
>> + GFP_KERNEL);
>> + if (!evts)
>> + return -ENOMEM;
>> +
>> + for (i = 0; i < nr_evts; i++) {
>> + sg_init_one(sg, &evts[i], sizeof(*evts));
>> + ret = virtqueue_add_inbuf(vq, sg, 1, &evts[i], GFP_KERNEL);
> who does the deallocation of evts?
I think it should be viommu_remove, which should also remove the
virtqueues. I'll add this.
Thanks,
Jean
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