Re: [Qemu-devel] [PATCH 0/4] exec: address space translation cleanups

[Paolo Bonzini]

On 16/05/2017 18:51, Maxime Coquelin wrote:
>>
>> I faced the problem the old patch fixes when declaring and attaching
>> an IOMMU device, but booting the kernel with intel_iommu=off.
>>
>> I tested again with patches 1 & 4 of your series, and I confirm it
>> fixes the issue:
>> Tested-by: Maxime Coquelin <address@hidden>
> 
> I did some more testing with my "vhost-user IOMMU" setup, and the series
> actually breaks with IOMMU device attached, and intel_iommu=on.
> 
> The main difference with the previous passing test is the guest RAM
> size. In the working setup, it is 2G of 2M hugepages, vs. 4G of 2M
> hugepages in the failing one. Note that I also reproduce with
> vhost-kernel backend.
> 
> The error happens in the first vhost_device_iotlb_miss() call:
> qemu-system-x86_64: Fail to lookup the translated address b5d7c000
> 
> I don't have the root cause yet, I'll keep you updated.

I suppose it is patch 4?

Paolo