Re: [PATCH v9 8/9] virtio-iommu: Implement probe request

[Auger Eric]

Hi Bharat,
On 4/23/20 6:09 PM, Jean-Philippe Brucker wrote:
> Hi Bharat,
> 
> A few more things found while rebasing
> 
> On Mon, Mar 23, 2020 at 02:16:16PM +0530, Bharat Bhushan wrote:
>> This patch implements the PROBE request. Currently supported
>> page size mask per endpoint is returned. Also append a NONE
>> property in the end.
>>
>> Signed-off-by: Bharat Bhushan <address@hidden>
>> Signed-off-by: Eric Auger <address@hidden>
>> ---
>>  include/standard-headers/linux/virtio_iommu.h |   6 +
>>  hw/virtio/virtio-iommu.c                      | 161 +++++++++++++++++-
>>  hw/virtio/trace-events                        |   2 +
>>  3 files changed, 166 insertions(+), 3 deletions(-)
>>
>> diff --git a/include/standard-headers/linux/virtio_iommu.h 
>> b/include/standard-headers/linux/virtio_iommu.h
>> index b9443b83a1..8a0d47b907 100644
>> --- a/include/standard-headers/linux/virtio_iommu.h
>> +++ b/include/standard-headers/linux/virtio_iommu.h
>> @@ -111,6 +111,7 @@ struct virtio_iommu_req_unmap {
>>  
>>  #define VIRTIO_IOMMU_PROBE_T_NONE           0
>>  #define VIRTIO_IOMMU_PROBE_T_RESV_MEM               1
>> +#define VIRTIO_IOMMU_PROBE_T_PAGE_SIZE_MASK 2
>>  
>>  #define VIRTIO_IOMMU_PROBE_T_MASK           0xfff
>>  
>> @@ -130,6 +131,11 @@ struct virtio_iommu_probe_resv_mem {
>>      uint64_t                                        end;
>>  };
>>  
>> +struct virtio_iommu_probe_pgsize_mask {
>> +    struct virtio_iommu_probe_property      head;
>> +    uint64_t                                pgsize_bitmap;
>> +};
>> +
>>  struct virtio_iommu_req_probe {
>>      struct virtio_iommu_req_head            head;
>>      uint32_t                                        endpoint;
>> diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
>> index 747e3cf1da..63fbacdcdc 100644
>> --- a/hw/virtio/virtio-iommu.c
>> +++ b/hw/virtio/virtio-iommu.c
>> @@ -38,6 +38,10 @@
>>  
>>  /* Max size */
>>  #define VIOMMU_DEFAULT_QUEUE_SIZE 256
>> +#define VIOMMU_PROBE_SIZE 512
>> +
>> +#define SUPPORTED_PROBE_PROPERTIES (\
>> +    1 << VIRTIO_IOMMU_PROBE_T_PAGE_SIZE_MASK)
>>  
>>  typedef struct VirtIOIOMMUDomain {
>>      uint32_t id;
>> @@ -62,6 +66,13 @@ typedef struct VirtIOIOMMUMapping {
>>      uint32_t flags;
>>  } VirtIOIOMMUMapping;
>>  
>> +typedef struct VirtIOIOMMUPropBuffer {
>> +    VirtIOIOMMUEndpoint *endpoint;
>> +    size_t filled;
>> +    uint8_t *start;
>> +    bool error;
> 
> It doesn't seem like bufstate->error gets used anywhere
maybe rebase your work on
[PATCH for-4.2 v10 10/15] virtio-iommu: Implement probe request
which tests it.

Also in
[Qemu-devel] [PATCH for-4.2 v10 10/15] virtio-iommu: Implement probe request
I changed the implementation to keep it simpler.

Thanks

Eric
> 
>> +} VirtIOIOMMUPropBuffer;
>> +
>>  static inline uint16_t virtio_iommu_get_bdf(IOMMUDevice *dev)
>>  {
>>      return PCI_BUILD_BDF(pci_bus_num(dev->bus), dev->devfn);
>> @@ -490,6 +501,114 @@ static int virtio_iommu_unmap(VirtIOIOMMU *s,
>>      return ret;
>>  }
>>  
>> +static int virtio_iommu_fill_none_prop(VirtIOIOMMUPropBuffer *bufstate)
>> +{
>> +    struct virtio_iommu_probe_property *prop;
>> +
>> +    prop = (struct virtio_iommu_probe_property *)
>> +                (bufstate->start + bufstate->filled);
>> +    prop->type = 0;
>> +    prop->length = 0;
>> +    bufstate->filled += sizeof(*prop);
>> +    trace_virtio_iommu_fill_none_property(bufstate->endpoint->id);
>> +    return 0;
>> +}
>> +
>> +static int virtio_iommu_fill_page_size_mask(VirtIOIOMMUPropBuffer *bufstate)
>> +{
>> +    struct virtio_iommu_probe_pgsize_mask *page_size_mask;
>> +    size_t prop_size = sizeof(*page_size_mask);
>> +    VirtIOIOMMUEndpoint *ep = bufstate->endpoint;
>> +    VirtIOIOMMU *s = ep->viommu;
>> +    IOMMUDevice *sdev;
>> +
>> +    if (bufstate->filled + prop_size >= VIOMMU_PROBE_SIZE) {
>> +        bufstate->error = true;
>> +        /* get the traversal stopped by returning true */
>> +        return true;
>> +    }
>> +
>> +    page_size_mask = (struct virtio_iommu_probe_pgsize_mask *)
>> +                     (bufstate->start + bufstate->filled);
>> +
>> +    page_size_mask->head.type = VIRTIO_IOMMU_PROBE_T_PAGE_SIZE_MASK;
>> +    page_size_mask->head.length = prop_size;
>> +    QLIST_FOREACH(sdev, &s->notifiers_list, next) {
>> +        if (ep->id == sdev->devfn) {
>> +            page_size_mask->pgsize_bitmap = sdev->page_size_mask;
> 
> Do we need a cpu_to_le64 here?
> 
>> +    }
>> +    }
>> +    bufstate->filled += sizeof(*page_size_mask);
>> +    trace_virtio_iommu_fill_pgsize_mask_property(bufstate->endpoint->id,
>> +                                                 
>> page_size_mask->pgsize_bitmap,
>> +                                                 bufstate->filled);
>> +    return false;
>> +}
>> +
>> +/* Fill the properties[] buffer with properties of type @type */
>> +static int virtio_iommu_fill_property(int type,
>> +                                      VirtIOIOMMUPropBuffer *bufstate)
>> +{
>> +    int ret = -ENOSPC;
>> +
>> +    if (bufstate->filled + sizeof(struct virtio_iommu_probe_property)
>> +            >= VIOMMU_PROBE_SIZE) {
>> +        /* no space left for the header */
>> +        bufstate->error = true;
>> +        goto out;
>> +    }
>> +
>> +    switch (type) {
>> +    case VIRTIO_IOMMU_PROBE_T_NONE:
>> +        ret = virtio_iommu_fill_none_prop(bufstate);
>> +        break;
>> +    case VIRTIO_IOMMU_PROBE_T_PAGE_SIZE_MASK:
>> +    {
>> +        ret = virtio_iommu_fill_page_size_mask(bufstate);
>> +    break;
>> +    }
>> +    default:
>> +        ret = -ENOENT;
>> +        break;
>> +    }
>> +out:
>> +    if (ret) {
>> +        error_report("%s property of type=%d could not be filled (%d),"
>> +                     " remaining size = 0x%lx",
>> +                     __func__, type, ret, bufstate->filled);
>> +    }
>> +    return ret;
>> +}
>> +
>> +/**
>> + * virtio_iommu_probe - Fill the probe request buffer with all
>> + * the properties the device is able to return and add a NONE
>> + * property at the end. @buf points to properties[].
>> + */
>> +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);
>> +    VirtIOIOMMUEndpoint *ep = virtio_iommu_get_endpoint(s, ep_id);
>> +    int16_t prop_types = SUPPORTED_PROBE_PROPERTIES, type;
>> +    VirtIOIOMMUPropBuffer bufstate = {.start = buf, .filled = 0,
>> +                                       .error = false, .endpoint = ep};
> 
> Probably need to check if ep is valid before going further
> 
>> +
>> +    while ((type = ctz32(prop_types)) != 32) {
>> +        if (virtio_iommu_fill_property(type, &bufstate)) {
>> +            goto failure;
>> +        }
>> +        prop_types &= ~(1 << type);
>> +    }
>> +    if (virtio_iommu_fill_property(VIRTIO_IOMMU_PROBE_T_NONE, &bufstate)) {
>> +        goto failure;
>> +    }
> 
> We got rid of the NONE property in the spec, now there is: 
> 
>  "If the device doesn’t fill all probe_size bytes with properties, it
>   SHOULD fill the remaining bytes of properties with zeroes."
> 
> So I think you can get rid of virtio_iommu_fill_none_prop() and fill the
> rest of the buffer with zeroes here instead.
> 
> Thanks,
> Jean
> 
>> +    return VIRTIO_IOMMU_S_OK;
>> +failure:
>> +    return VIRTIO_IOMMU_S_INVAL;
>> +}
>> +
>>  static int virtio_iommu_iov_to_req(struct iovec *iov,
>>                                     unsigned int iov_cnt,
>>                                     void *req, size_t req_sz)
>> @@ -519,6 +638,17 @@ 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);
>> @@ -564,17 +694,33 @@ 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);
>>      }
>> @@ -634,16 +780,23 @@ static IOMMUTLBEntry 
>> virtio_iommu_translate(IOMMUMemoryRegion *mr, hwaddr addr,
>>      VirtIOIOMMUEndpoint *ep;
>>      uint32_t sid, flags;
>>      bool bypass_allowed;
>> +    hwaddr addr_mask;
>>      bool found;
>>  
>>      interval.low = addr;
>>      interval.high = addr + 1;
>>  
>> +    if (sdev->page_size_mask) {
>> +        addr_mask = (1 << ctz32(sdev->page_size_mask)) - 1;
>> +    } else {
>> +        addr_mask = (1 << ctz32(s->config.page_size_mask)) - 1;
>> +    }
>> +
>>      IOMMUTLBEntry entry = {
>>          .target_as = &address_space_memory,
>>          .iova = addr,
>>          .translated_addr = addr,
>> -        .addr_mask = (1 << ctz32(s->config.page_size_mask)) - 1,
>> +        .addr_mask = addr_mask,
>>          .perm = IOMMU_NONE,
>>      };
>>  
>> @@ -831,6 +984,7 @@ 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);
>> @@ -840,6 +994,7 @@ 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 8bae651191..b0a6e4bda3 100644
>> --- a/hw/virtio/trace-events
>> +++ b/hw/virtio/trace-events
>> @@ -76,3 +76,5 @@ virtio_iommu_report_fault(uint8_t reason, uint32_t flags, 
>> uint32_t endpoint, uin
>>  virtio_iommu_notify_map(const char *name, uint64_t iova, uint64_t paddr, 
>> uint64_t map_size) "mr=%s iova=0x%"PRIx64" pa=0x%" PRIx64" size=0x%"PRIx64
>>  virtio_iommu_notify_unmap(const char *name, uint64_t iova, uint64_t 
>> map_size) "mr=%s iova=0x%"PRIx64" size=0x%"PRIx64
>>  virtio_iommu_remap(uint64_t iova, uint64_t pa, uint64_t size) 
>> "iova=0x%"PRIx64" pa=0x%" PRIx64" size=0x%"PRIx64""
>> +virtio_iommu_fill_none_property(uint32_t devid) "devid=%d"
>> +virtio_iommu_fill_pgsize_mask_property(uint32_t devid, uint64_t 
>> pgsize_mask, size_t filled) "dev= %d, pgsize_mask=0x%"PRIx64" filled=0x%lx"
>> -- 
>> 2.17.1
>>
>