Re: [PATCH 2/5] virtio-iommu: Implement RESV_MEM probe request

[Auger Eric <eric.auger@redhat.com>]

Hi Jean,
On 5/8/20 11:26 AM, Jean-Philippe Brucker wrote:
> On Thu, May 07, 2020 at 04:31:58PM +0200, Eric Auger wrote:
>> +static ssize_t virtio_iommu_fill_resv_mem_prop(VirtIOIOMMU *s, uint32_t ep,
>> +                                               uint8_t *buf, size_t free)
>> +{
>> +    struct virtio_iommu_probe_resv_mem prop = {};
>> +    size_t size = sizeof(prop), length = size - sizeof(prop.head), total;
>> +    int i;
>> +
>> +    total = size * s->nb_reserved_regions;
>> +
>> +    if (total > free) {
>> +        return -ENOSPC;
>> +    }
>> +
>> +    for (i = 0; i < s->nb_reserved_regions; i++) {
>> +        prop.head.type = VIRTIO_IOMMU_PROBE_T_RESV_MEM;
> 
> cpu_to_le16
> 
>> +        prop.head.length = cpu_to_le64(length);
> 
> same here
> 
>> +        prop.subtype = cpu_to_le64(s->reserved_regions[i].type);
> 
> and subtype is a byte

All fixed. Thanks for spotting this.
> 
>> +        prop.start = cpu_to_le64(s->reserved_regions[i].low);
>> +        prop.end = cpu_to_le64(s->reserved_regions[i].high);
>> +
>> +        memcpy(buf, &prop, size);
>> +
>> +        trace_virtio_iommu_fill_resv_property(ep, prop.subtype,
>> +                                              prop.start, prop.end);
>> +        buf += size;
>> +    }
>> +    return total;
>> +}
>> +
>> +/**
>> + * virtio_iommu_probe - Fill the probe request buffer with
>> + * the properties the device is able to return and add a NONE
>> + * property at the end.
>> + */
>> +static int virtio_iommu_probe(VirtIOIOMMU *s,
>> +                              struct virtio_iommu_req_probe *req,
>> +                              uint8_t *buf)
>> +{
>> +    uint32_t ep_id = le32_to_cpu(req->endpoint);
> 
> I think we should check that the endpoint ID is sane even if we're not
> using it at the moment (it is a SHOULD in the spec, and the page size mask
> patch will need the ep anyway).
OK
> 
>> +    struct virtio_iommu_probe_property last = {};
>> +    size_t free = VIOMMU_PROBE_SIZE - sizeof(last);
> 
> last isn't needed, you can fill the whole probe buffer with valid
> properties
yep. This is a reminder from none prop.
> 
>> +    ssize_t count;
>> +
>> +    count = virtio_iommu_fill_resv_mem_prop(s, ep_id, buf, free);
>> +    if (count < 0) {
>> +            return VIRTIO_IOMMU_S_INVAL;
> 
> indentation?
yes.

Thank you for the review

Eric
> 
> Thanks,
> Jean
> 
>> +    }
>> +    buf += count;
>> +    free -= count;
>> +
>> +    /* Fill the rest with zeroes */
>> +    memset(buf, 0, free);
>> +
>> +    return VIRTIO_IOMMU_S_OK;
>> +}
>> +
>>  static int virtio_iommu_iov_to_req(struct iovec *iov,
>>                                     unsigned int iov_cnt,
>>                                     void *req, size_t req_sz)
>> @@ -407,6 +464,17 @@ virtio_iommu_handle_req(detach)
>>  virtio_iommu_handle_req(map)
>>  virtio_iommu_handle_req(unmap)
>>  
>> +static int virtio_iommu_handle_probe(VirtIOIOMMU *s,
>> +                                     struct iovec *iov,
>> +                                     unsigned int iov_cnt,
>> +                                     uint8_t *buf)
>> +{
>> +    struct virtio_iommu_req_probe req;
>> +    int ret = virtio_iommu_iov_to_req(iov, iov_cnt, &req, sizeof(req));
>> +
>> +    return ret ? ret : virtio_iommu_probe(s, &req, buf);
>> +}
>> +
>>  static void virtio_iommu_handle_command(VirtIODevice *vdev, VirtQueue *vq)
>>  {
>>      VirtIOIOMMU *s = VIRTIO_IOMMU(vdev);
>> @@ -452,17 +520,33 @@ static void virtio_iommu_handle_command(VirtIODevice *vdev, VirtQueue *vq)
>>          case VIRTIO_IOMMU_T_UNMAP:
>>              tail.status = virtio_iommu_handle_unmap(s, iov, iov_cnt);
>>              break;
>> +        case VIRTIO_IOMMU_T_PROBE:
>> +        {
>> +            struct virtio_iommu_req_tail *ptail;
>> +            uint8_t *buf = g_malloc0(s->config.probe_size + sizeof(tail));
>> +
>> +            ptail = (struct virtio_iommu_req_tail *)
>> +                        (buf + s->config.probe_size);
>> +            ptail->status = virtio_iommu_handle_probe(s, iov, iov_cnt, buf);
>> +
>> +            sz = iov_from_buf(elem->in_sg, elem->in_num, 0,
>> +                              buf, s->config.probe_size + sizeof(tail));
>> +            g_free(buf);
>> +            assert(sz == s->config.probe_size + sizeof(tail));
>> +            goto push;
>> +        }
>>          default:
>>              tail.status = VIRTIO_IOMMU_S_UNSUPP;
>>          }
>> -        qemu_mutex_unlock(&s->mutex);
>>  
>>  out:
>>          sz = iov_from_buf(elem->in_sg, elem->in_num, 0,
>>                            &tail, sizeof(tail));
>>          assert(sz == sizeof(tail));
>>  
>> -        virtqueue_push(vq, elem, sizeof(tail));
>> +push:
>> +        qemu_mutex_unlock(&s->mutex);
>> +        virtqueue_push(vq, elem, sz);
>>          virtio_notify(vdev, vq);
>>          g_free(elem);
>>      }
>> @@ -667,6 +751,7 @@ static void virtio_iommu_device_realize(DeviceState *dev, Error **errp)
>>      s->config.page_size_mask = TARGET_PAGE_MASK;
>>      s->config.input_range.end = -1UL;
>>      s->config.domain_range.end = 32;
>> +    s->config.probe_size = VIOMMU_PROBE_SIZE;
>>  
>>      virtio_add_feature(&s->features, VIRTIO_RING_F_EVENT_IDX);
>>      virtio_add_feature(&s->features, VIRTIO_RING_F_INDIRECT_DESC);
>> @@ -676,6 +761,7 @@ static void virtio_iommu_device_realize(DeviceState *dev, Error **errp)
>>      virtio_add_feature(&s->features, VIRTIO_IOMMU_F_MAP_UNMAP);
>>      virtio_add_feature(&s->features, VIRTIO_IOMMU_F_BYPASS);
>>      virtio_add_feature(&s->features, VIRTIO_IOMMU_F_MMIO);
>> +    virtio_add_feature(&s->features, VIRTIO_IOMMU_F_PROBE);
>>  
>>      qemu_mutex_init(&s->mutex);
>>  
>> diff --git a/hw/virtio/trace-events b/hw/virtio/trace-events
>> index e83500bee9..5550475691 100644
>> --- a/hw/virtio/trace-events
>> +++ b/hw/virtio/trace-events
>> @@ -73,3 +73,4 @@ virtio_iommu_get_domain(uint32_t domain_id) "Alloc domain=%d"
>>  virtio_iommu_put_domain(uint32_t domain_id) "Free domain=%d"
>>  virtio_iommu_translate_out(uint64_t virt_addr, uint64_t phys_addr, uint32_t sid) "0x%"PRIx64" -> 0x%"PRIx64 " for sid=%d"
>>  virtio_iommu_report_fault(uint8_t reason, uint32_t flags, uint32_t endpoint, uint64_t addr) "FAULT reason=%d flags=%d endpoint=%d address =0x%"PRIx64
>> +virtio_iommu_fill_resv_property(uint32_t devid, uint8_t subtype, uint64_t start, uint64_t end) "dev= %d, type=%d start=0x%"PRIx64" end=0x%"PRIx64
>> -- 
>> 2.20.1
>>
>