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: Tuesday, May 12, 2020 8:39 AM
> 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 5/12/20 5:03 AM, Bharat Bhushan wrote:
> > 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.
> 
> You mean for debugging the driver? I don't think this is the purpose of this 
> device.

Yes for debugging purpose only.

Thanks
-Bharat

> 
> Thanks
> 
> Eric
> >
> > 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
> >>>>>
> >>>>>
> >>>
> >