Re: [Qemu-arm] [PATCH 15/27] iommu: Add IOMMU index argument to notifier APIs

[Peter Maydell]

On 23 May 2018 at 10:08, Alex Bennée <address@hidden> wrote:
>
> Peter Maydell <address@hidden> writes:
>
>> Add support for multiple IOMMU indexes to the IOMMU notifier APIs.
>> When initializing a notifier with iommu_notifier_init(), the caller
>> must pass the IOMMU index that it is interested in. When a change
>> happens, the IOMMU implementation must pass
>> memory_region_notify_iommu() the IOMMU index that has changed and
>> that notifiers must be called for.
>>
>> IOMMUs which support only a single index don't need to change.
>> Callers which only really support working with IOMMUs with a single
>> index can use the result of passing MEMTXATTRS_UNSPECIFIED to
>> memory_region_iommu_attrs_to_index().
>>
>> Signed-off-by: Peter Maydell <address@hidden>
>> ---
>>  include/exec/memory.h    | 11 ++++++++++-
>>  hw/i386/intel_iommu.c    |  4 ++--
>>  hw/ppc/spapr_iommu.c     |  2 +-
>>  hw/s390x/s390-pci-inst.c |  4 ++--
>>  hw/vfio/common.c         |  6 +++++-
>>  hw/virtio/vhost.c        |  7 ++++++-
>>  memory.c                 |  8 +++++++-
>>  7 files changed, 33 insertions(+), 9 deletions(-)
>>
>> diff --git a/include/exec/memory.h b/include/exec/memory.h
>> index f6226fb263..4e6b125add 100644
>> --- a/include/exec/memory.h
>> +++ b/include/exec/memory.h
>> @@ -71,6 +71,7 @@ struct IOMMUTLBEntry {
>>      hwaddr           iova;
>>      hwaddr           translated_addr;
>>      hwaddr           addr_mask;  /* 0xfff = 4k translation */
>> +    int              iommu_idx;
>>      IOMMUAccessFlags perm;
>>  };
>>
>> @@ -98,18 +99,21 @@ struct IOMMUNotifier {
>>      /* Notify for address space range start <= addr <= end */
>>      hwaddr start;
>>      hwaddr end;
>> +    int iommu_idx;
>
> Its a minor thing but are we ever expecting iommu_idx to ever be
> negative?

Coming back to this one -- no, we don't expect negative iommu_idxs.
But on the other hand we don't ever expect negative TCG mmu_indexes
either, and we use 'int' for those...

thanks
-- PMM