Hi Alex,

On 6/4/19 12:32 AM, Alex Williamson wrote:
> On Sun, 26 May 2019 18:09:59 +0200
> Eric Auger <eric.au...@redhat.com> wrote:
> 
>> This patch adds the VFIO_IOMMU_BIND/UNBIND_MSI ioctl which aim
>> to pass/withdraw the guest MSI binding to/from the host.
>>
>> Signed-off-by: Eric Auger <eric.au...@redhat.com>
>>
>> ---
>> v6 -> v7:
>> - removed the dev arg
>>
>> v3 -> v4:
>> - add UNBIND
>> - unwind on BIND error
>>
>> v2 -> v3:
>> - adapt to new proto of bind_guest_msi
>> - directly use vfio_iommu_for_each_dev
>>
>> v1 -> v2:
>> - s/vfio_iommu_type1_guest_msi_binding/vfio_iommu_type1_bind_guest_msi
>> ---
>>  drivers/vfio/vfio_iommu_type1.c | 64 +++++++++++++++++++++++++++++++++
>>  include/uapi/linux/vfio.h       | 29 +++++++++++++++
>>  2 files changed, 93 insertions(+)
>>
>> diff --git a/drivers/vfio/vfio_iommu_type1.c 
>> b/drivers/vfio/vfio_iommu_type1.c
>> index 6fda4fbc9bfa..18142cb078a3 100644
>> --- a/drivers/vfio/vfio_iommu_type1.c
>> +++ b/drivers/vfio/vfio_iommu_type1.c
>> @@ -1832,6 +1832,42 @@ static int vfio_cache_inv_fn(struct device *dev, void 
>> *data)
>>      return iommu_cache_invalidate(dc->domain, dev, &ustruct->info);
>>  }
>>  
>> +static int
>> +vfio_bind_msi(struct vfio_iommu *iommu,
>> +          dma_addr_t giova, phys_addr_t gpa, size_t size)
>> +{
>> +    struct vfio_domain *d;
>> +    int ret = 0;
>> +
>> +    mutex_lock(&iommu->lock);
>> +
>> +    list_for_each_entry(d, &iommu->domain_list, next) {
>> +            ret = iommu_bind_guest_msi(d->domain, giova, gpa, size);
>> +            if (ret)
>> +                    goto unwind;
>> +    }
>> +    goto unlock;
>> +unwind:
>> +    list_for_each_entry_continue_reverse(d, &iommu->domain_list, next) {
>> +            iommu_unbind_guest_msi(d->domain, giova);
>> +    }
>> +unlock:
>> +    mutex_unlock(&iommu->lock);
>> +    return ret;
>> +}
>> +
>> +static void
>> +vfio_unbind_msi(struct vfio_iommu *iommu, dma_addr_t giova)
>> +{
>> +    struct vfio_domain *d;
>> +
>> +    mutex_lock(&iommu->lock);
>> +    list_for_each_entry(d, &iommu->domain_list, next) {
>> +            iommu_unbind_guest_msi(d->domain, giova);
>> +    }
>> +    mutex_unlock(&iommu->lock);
>> +}
>> +
>>  static long vfio_iommu_type1_ioctl(void *iommu_data,
>>                                 unsigned int cmd, unsigned long arg)
>>  {
>> @@ -1936,6 +1972,34 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
>>                                          &ustruct);
>>              mutex_unlock(&iommu->lock);
>>              return ret;
>> +    } else if (cmd == VFIO_IOMMU_BIND_MSI) {
>> +            struct vfio_iommu_type1_bind_msi ustruct;
>> +
>> +            minsz = offsetofend(struct vfio_iommu_type1_bind_msi,
>> +                                size);
>> +
>> +            if (copy_from_user(&ustruct, (void __user *)arg, minsz))
>> +                    return -EFAULT;
>> +
>> +            if (ustruct.argsz < minsz || ustruct.flags)
>> +                    return -EINVAL;
>> +
>> +            return vfio_bind_msi(iommu, ustruct.iova, ustruct.gpa,
>> +                                 ustruct.size);
>> +    } else if (cmd == VFIO_IOMMU_UNBIND_MSI) {
>> +            struct vfio_iommu_type1_unbind_msi ustruct;
>> +
>> +            minsz = offsetofend(struct vfio_iommu_type1_unbind_msi,
>> +                                iova);
>> +
>> +            if (copy_from_user(&ustruct, (void __user *)arg, minsz))
>> +                    return -EFAULT;
>> +
>> +            if (ustruct.argsz < minsz || ustruct.flags)
>> +                    return -EINVAL;
>> +
>> +            vfio_unbind_msi(iommu, ustruct.iova);
>> +            return 0;
>>      }
>>  
>>      return -ENOTTY;
>> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
>> index 055aa9b9745a..2774a1ab37ae 100644
>> --- a/include/uapi/linux/vfio.h
>> +++ b/include/uapi/linux/vfio.h
>> @@ -798,6 +798,35 @@ struct vfio_iommu_type1_cache_invalidate {
>>  };
>>  #define VFIO_IOMMU_CACHE_INVALIDATE      _IO(VFIO_TYPE, VFIO_BASE + 24)
>>  
>> +/**
>> + * VFIO_IOMMU_BIND_MSI - _IOWR(VFIO_TYPE, VFIO_BASE + 25,
>> + *                  struct vfio_iommu_type1_bind_msi)
>> + *
>> + * Pass a stage 1 MSI doorbell mapping to the host so that this
>> + * latter can build a nested stage2 mapping
>> + */
>> +struct vfio_iommu_type1_bind_msi {
>> +    __u32   argsz;
>> +    __u32   flags;
>> +    __u64   iova;
>> +    __u64   gpa;
>> +    __u64   size;
>> +};
>> +#define VFIO_IOMMU_BIND_MSI      _IO(VFIO_TYPE, VFIO_BASE + 25)
>> +
>> +/**
>> + * VFIO_IOMMU_UNBIND_MSI - _IOWR(VFIO_TYPE, VFIO_BASE + 26,
>> + *                  struct vfio_iommu_type1_unbind_msi)
>> + *
>> + * Unregister an MSI mapping
>> + */
>> +struct vfio_iommu_type1_unbind_msi {
>> +    __u32   argsz;
>> +    __u32   flags;
>> +    __u64   iova;
>> +};
>> +#define VFIO_IOMMU_UNBIND_MSI      _IO(VFIO_TYPE, VFIO_BASE + 26)
>> +
>>  /* -------- Additional API for SPAPR TCE (Server POWERPC) IOMMU -------- */
>>  
>>  /*
> 
> And another pair of ioctls.  Maybe think about how we can reduce the
> ioctl bloat of this series.  I don't want to impose an awkward
> interface for the sake of fewer ioctls, but I also don't want us
> casually burning through ioctls.
OK, understood.

Thanks

Eric
> 
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