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

[Bharat Bhushan]

Hi Eric,

> -----Original Message-----
> From: Auger Eric <address@hidden>
> Sent: Thursday, March 26, 2020 9:18 PM
> To: Bharat Bhushan <address@hidden>; address@hidden;
> address@hidden; address@hidden; address@hidden;
> address@hidden; address@hidden; Tomasz Nowicki [C]
> <address@hidden>; address@hidden; address@hidden; qemu-
> address@hidden; address@hidden; address@hidden; jean-
> address@hidden; address@hidden
> Subject: [EXT] Re: [PATCH v9 8/9] virtio-iommu: Implement probe request
> 
> External Email
> 
> ----------------------------------------------------------------------
> Hi Bharat
> 
> On 3/23/20 9:46 AM, 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 +
> Changes to virtio_iommu.h should be in a separate patch you should use
> ./scripts/update-linux-headers.sh See for instance:
> ddda37483d  linux-headers: update
> until the uapi updates are not upstream you can link to your kernel branch and
> mention this is a temporary linux header update or partial if you just want 
> to pick
> up the iommu.h changes.

yes, I am sorry.

> 
> >  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;
> > +} 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;
> > +   }
> > +    }
> > +    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);
> I don't think you want to fill the property of each EP. Only for those whose 
> sdev-
> >page_size_mask was properly set. For instance if you mix virtio and vfio 
> >devices,
> virtio ones won't have this field set.

This something I am looking for clarification ( asked in spec document patch). 
Copy pasting same here:

What some clarification about two page-size-mask configurations available.
 - Global configuration for page-size-mask
 - per endpoint page-size-mask configuration

PAGE_SIZE_MASK probe for and endpoint can return zero or non-zero value.
If it returns non-zero value than it will override the global configuration.
If PAGE_SIZE_MASK probe for and endpoint return zero value than global 
page-size-mask configuration will be used.

Is that correct?

Thanks
-Bharat

> > +   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};
> > +
> > +    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;
> > +    }
> > +    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;
> > +    }
> This change does not belong ot this patch. Rather belongs to
> "virtio-iommu: set supported page size mask"

Thanks for pointing, will change.

Thanks
-Bharat

> > +
> >      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"
> >
> Thanks
> 
> Eric