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

[Bharat Bhushan]

On Fri, Apr 24, 2020 at 7:22 PM Auger Eric <address@hidden> wrote:
>
> 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.

This was the staring point for me, As of now i moved away from "error"
from above struct.

>
> 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?

Ack, yes, even head.type and head.length needed  cpu_to_le16().

> >
> >> +    }
> >> +    }
> >> +    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

yes, will take care

> >
> >> +
> >> +    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.

will do changes accordingly.

Stay Safe !!

Thanks
-Bharat
> >
> > 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
> >>
> >
>