[dpdk-dev] [PATCH] eal/vfio: fix sPAPR IOMMU mapping

[Burakov, Anatoly]

On 06-Aug-18 10:50 AM, Thomas Monjalon wrote:
> 06/08/2018 10:43, Takeshi Yoshimura:
>> Commit 73a639085938 ("vfio: allow to map other memory regions")
>> introduced a bug in sPAPR IOMMU mapping. The commit removed necessary
>> ioctl with VFIO_IOMMU_SPAPR_REGISTER_MEMORY. Also, vfio_spapr_map_walk
>> should call vfio_spapr_dma_do_map instead of vfio_spapr_dma_mem_map.
> 
> This is fixing an old patch:
> 	http://git.dpdk.org/dpdk/commit/?id=73a639085938
> 
>> Fixes: 73a639085938 ("vfio: allow to map other memory regions")
> 
> You probably want it to be backported in previous release,
> so you need to add Cc: stable at dpdk.org
> 
>> Signed-off-by: Takeshi Yoshimura <tyos at jp.ibm.com>
> 
> It is common to have bugs in sPAPR implementation.
> How can we be sure this one is OK?
> Should it be added in last minute of 18.08?
> Or can it wait 18.11?
> 
> Adding Anatoly and Chao who are maintainers to decide.
> 

The patch appears to be correct - we did have a 
VFIO_IOMMU_SPAPR_REGISTER_MEMORY ioctl in the old map() function, but 
not in the new one.

However, i agree with Thomas - without more testing from other sPAPR 
users/IBM, i would be hesitant to allow it in at the last minute. In any 
case, this code has been there for a while and no one has reported any 
issues - so this can probably wait until 18.11, seeing how this codepath 
is so popular :)

-- 
Thanks,
Anatoly