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

[Jean-Philippe Brucker]

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

> +        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).

> +    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

> +    ssize_t count;
> +
> +    count = virtio_iommu_fill_resv_mem_prop(s, ep_id, buf, free);
> +    if (count < 0) {
> +            return VIRTIO_IOMMU_S_INVAL;

indentation?

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
>