Re: [Qemu-devel] [PATCH qemu v14 12/18] vfio: Check that IOMMU MR translates to system address space

[Alexey Kardashevskiy <aik@ozlabs.ru>]

On 03/23/2016 02:47 AM, Alex Williamson wrote:
> On Tue, 22 Mar 2016 14:05:15 +1100
> David Gibson <david@gibson.dropbear.id.au> wrote:
>
>> On Mon, Mar 21, 2016 at 06:47:00PM +1100, Alexey Kardashevskiy wrote:
>>> At the moment IOMMU MR only translate to the system memory.
>>> However if some new code changes this, we will need clear indication why
>>> it is not working so here is the check.
>>>
>>> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
>>
>> Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
>>
>> Alex, any chance we could merge this quickly, since it is a reasonable
>> sanity check even without the rest of the changes.
>
> It all sounds very theoretical to inspire some rush to merge it
> quickly, is there any chance we could actually hit this currently?


The chances are as big as chances that some platform starts supporting VFIO 
soon, for these new folks such a check would be a good piece of 
documentation or at least a warning trigger to ask a question in the lists.



>>> ---
>>> Changes:
>>> v14:
>>> * new to the series
>>> ---
>>>   hw/vfio/common.c | 6 ++++++
>>>   1 file changed, 6 insertions(+)
>>>
>>> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
>>> index 55723c9..9587c25 100644
>>> --- a/hw/vfio/common.c
>>> +++ b/hw/vfio/common.c
>>> @@ -266,6 +266,12 @@ static void vfio_iommu_map_notify(Notifier *n, void *data)
>>>
>>>       trace_vfio_iommu_map_notify(iova, iova + iotlb->addr_mask);
>>>
>>> +    if (iotlb->target_as != &address_space_memory) {
>>> +        error_report("Wrong target AS \"%s\", only system memory is allowed",
>>> +                     iotlb->target_as->name?iotlb->target_as->name:"noname");
>
> Spaces please.
>
>>> +        return;
>>> +    }
>>> +
>>>       /*
>>>        * The IOMMU TLB entry we have just covers translation through
>>>        * this IOMMU to its immediate target.  We need to translate
>>
>


-- 
Alexey