RE: [EXT] [PATCH v2 2/5] virtio-iommu: Implement RESV_MEM probe request

[Bharat Bhushan]

Hi Eric,

> -----Original Message-----
> From: Auger Eric <address@hidden>
> Sent: Monday, May 11, 2020 2:19 PM
> To: Bharat Bhushan <address@hidden>; address@hidden;
> address@hidden; address@hidden; address@hidden;
> address@hidden; address@hidden; address@hidden;
> address@hidden; address@hidden
> Subject: Re: [EXT] [PATCH v2 2/5] virtio-iommu: Implement RESV_MEM probe
> request
> 
> Hi Bharat,
> 
> On 5/11/20 10:42 AM, Bharat Bhushan wrote:
> > Hi Eric,
> >
> >> -----Original Message-----
> >> From: Auger Eric <address@hidden>
> >> Sent: Monday, May 11, 2020 12:26 PM
> >> To: Bharat Bhushan <address@hidden>; address@hidden;
> >> address@hidden; address@hidden; address@hidden;
> >> address@hidden; address@hidden; address@hidden;
> >> address@hidden; address@hidden
> >> Subject: Re: [EXT] [PATCH v2 2/5] virtio-iommu: Implement RESV_MEM
> >> probe request
> >>
> >> Hi Bharat,
> >> On 5/11/20 8:38 AM, Bharat Bhushan wrote:
> >>> Hi Eric,
> >>>
> >>>> -----Original Message-----
> >>>> From: Eric Auger <address@hidden>
> >>>> Sent: Friday, May 8, 2020 11:01 PM
> >>>> To: address@hidden; address@hidden;
> >>>> address@hidden; address@hidden;
> >>>> address@hidden; address@hidden; jean-
> >>>> address@hidden; Bharat Bhushan <address@hidden>;
> >>>> address@hidden; address@hidden; address@hidden
> >>>> Subject: [EXT] [PATCH v2 2/5] virtio-iommu: Implement RESV_MEM
> >>>> probe request
> >>>>
> >>>> External Email
> >>>>
> >>>> -------------------------------------------------------------------
> >>>> --
> >>>> - This patch implements the PROBE request. At the moment, only THE
> >>>> RESV_MEM property is handled. The first goal is to report iommu
> >>>> wide reserved regions such as the MSI regions set by the machine
> >>>> code. On
> >>>> x86 this will be the IOAPIC MSI region,
> >>>> [0xFEE00000 - 0xFEEFFFFF], on ARM this may be the ITS doorbell.
> >>>>
> >>>> In the future we may introduce per device reserved regions.
> >>>> This will be useful when protecting host assigned devices which may
> >>>> expose their own reserved regions
> >>>>
> >>>> Signed-off-by: Eric Auger <address@hidden>
> >>>>
> >>>> ---
> >>>>
> >>>> v1 -> v2:
> >>>> - move the unlock back to the same place
> >>>> - remove the push label and factorize the code after the out label
> >>>> - fix a bunch of cpu_to_leX according to the latest spec revision
> >>>> - do not remove sizeof(last) from free space
> >>>> - check the ep exists
> >>>> ---
> >>>>  include/hw/virtio/virtio-iommu.h |  2 +
> >>>>  hw/virtio/virtio-iommu.c         | 94 ++++++++++++++++++++++++++++++--
> >>>>  hw/virtio/trace-events           |  1 +
> >>>>  3 files changed, 93 insertions(+), 4 deletions(-)
> >>>>
> >>>> diff --git a/include/hw/virtio/virtio-iommu.h
> >>>> b/include/hw/virtio/virtio-iommu.h
> >>>> index e653004d7c..49eb105cd8 100644
> >>>> --- a/include/hw/virtio/virtio-iommu.h
> >>>> +++ b/include/hw/virtio/virtio-iommu.h
> >>>> @@ -53,6 +53,8 @@ typedef struct VirtIOIOMMU {
> >>>>      GHashTable *as_by_busptr;
> >>>>      IOMMUPciBus *iommu_pcibus_by_bus_num[PCI_BUS_MAX];
> >>>>      PCIBus *primary_bus;
> >>>> +    ReservedRegion *reserved_regions;
> >>>> +    uint32_t nb_reserved_regions;
> >>>>      GTree *domains;
> >>>>      QemuMutex mutex;
> >>>>      GTree *endpoints;
> >>>> diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
> >>>> index
> >>>> 22ba8848c2..35d772e021 100644
> >>>> --- a/hw/virtio/virtio-iommu.c
> >>>> +++ b/hw/virtio/virtio-iommu.c
> >>>> @@ -38,6 +38,7 @@
> >>>>
> >>>>  /* Max size */
> >>>>  #define VIOMMU_DEFAULT_QUEUE_SIZE 256
> >>>> +#define VIOMMU_PROBE_SIZE 512
> >>>>
> >>>>  typedef struct VirtIOIOMMUDomain {
> >>>>      uint32_t id;
> >>>> @@ -378,6 +379,65 @@ static int virtio_iommu_unmap(VirtIOIOMMU *s,
> >>>>      return ret;
> >>>>  }
> >>>>
> >>>> +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 = cpu_to_le16(VIRTIO_IOMMU_PROBE_T_RESV_MEM);
> >>>> +        prop.head.length = cpu_to_le16(length);
> >>>> +        prop.subtype = s->reserved_regions[i].type;
> >>>> +        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);
> >>>> +    size_t free = VIOMMU_PROBE_SIZE;
> >>>> +    ssize_t count;
> >>>> +
> >>>> +    if (!virtio_iommu_mr(s, ep_id)) {
> >>>> +        return VIRTIO_IOMMU_S_NOENT;
> >>>> +    }
> >>>> +
> >>>> +    count = virtio_iommu_fill_resv_mem_prop(s, ep_id, buf, free);
> >>>> +    if (count < 0) {
> >>>> +        return VIRTIO_IOMMU_S_INVAL;
> >>>> +    }
> >>>> +    buf += count;
> >>>> +    free -= count;
> >>>> +
> >>>> +    /* Fill the rest with zeroes */
> >>>> +    memset(buf, 0, free);
> >>>
> >>> No need to fill with zero here as "buf" is set to zero on allocation, no?
> >>
> >> You're right. I will remove this in the next version.
> >>
> >> Thanks
> >>
> >> Eric
> >>>
> >>> Thanks
> >>> -Bharat
> >>>
> >>>> +
> >>>> +    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) @@
> >>>> -407,15 +467,27 @@
> >>>> 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);
> >>>>      struct virtio_iommu_req_head head;
> >>>>      struct virtio_iommu_req_tail tail = {};
> >>>> +    size_t output_size = sizeof(tail), sz;
> >>>>      VirtQueueElement *elem;
> >>>>      unsigned int iov_cnt;
> >>>>      struct iovec *iov;
> >>>> -    size_t sz;
> >>>> +    void *buf = NULL;
> >>>>
> >>>>      for (;;) {
> >>>>          elem = virtqueue_pop(vq, sizeof(VirtQueueElement)); @@
> >>>> -452,6 +524,17 @@ 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:
> >
> > As per spec
> >   "
> >    If the device does not offer the VIRTIO_IOMMU_F_PROBE feature, and if the
> driver sends a VIRTIO_-
> >    IOMMU_T_PROBE request, then the device SHOULD NOT write the buffer and
> SHOULD set the used
> >    length to zero.
> >   "
> > So we should check if device supports "VIRTIO_IOMMU_F_PROBE" before
> proceed?
> But are the device and from that patch onwards we do support the
> VIRTIO_IOMMU_F_PROBE feature, right?

Yes I agree, do you think if for debugging one wants to try out without this 
feature then he should just disable VIRTIO_IOMMU_F_PROBE.

Thanks
-Bharat

> 
> Thanks
> 
> Eric
> >
> > Thanks
> > -Bharat
> >
> >>>> +        {
> >>>> +            struct virtio_iommu_req_tail *ptail;
> >>>> +
> >>>> +            output_size = s->config.probe_size + sizeof(tail);
> >>>> +            buf = g_malloc0(output_size);
> >>>> +
> >>>> +            ptail = (struct virtio_iommu_req_tail *)
> >>>> +                        (buf + s->config.probe_size);
> >>>> +            ptail->status = virtio_iommu_handle_probe(s, iov, iov_cnt, 
> >>>> buf);
> >>>> +        }
> >>>>          default:
> >>>>              tail.status = VIRTIO_IOMMU_S_UNSUPP;
> >>>>          }
> >>>> @@ -459,12 +542,13 @@ static void
> >>>> virtio_iommu_handle_command(VirtIODevice *vdev, VirtQueue *vq)
> >>>>
> >>>>  out:
> >>>>          sz = iov_from_buf(elem->in_sg, elem->in_num, 0,
> >>>> -                          &tail, sizeof(tail));
> >>>> -        assert(sz == sizeof(tail));
> >>>> +                          buf ? buf : &tail, output_size);
> >>>> +        assert(sz == output_size);
> >>>>
> >>>> -        virtqueue_push(vq, elem, sizeof(tail));
> >>>> +        virtqueue_push(vq, elem, sz);
> >>>>          virtio_notify(vdev, vq);
> >>>>          g_free(elem);
> >>>> +        g_free(buf);
> >>>>      }
> >>>>  }
> >>>>
> >>>> @@ -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
> >>>
> >>>
> >