[PATCH v8 00/18] KVM PCIe/MSI passthrough on ARM/ARM64 and IOVA reserved regions

Auger Eric eric.auger at redhat.com
Mon Jan 16 01:07:46 PST 2017

Hi Tomasz,

On 13/01/2017 14:59, Tomasz Nowicki wrote:
> Hello Eric,
> On 11.01.2017 10:41, Eric Auger wrote:
>> Following LPC discussions, we now report reserved regions through
>> the iommu-group sysfs reserved_regions attribute file.
>> Reserved regions are populated through the IOMMU get_resv_region
>> callback (former get_dm_regions), now implemented by amd-iommu,
>> intel-iommu and arm-smmu:
>> - the intel-iommu reports the [0xfee00000 - 0xfeefffff] MSI window
>>   as a reserved region and RMRR regions as direct-mapped regions.
>> - the amd-iommu reports device direct mapped regions, the MSI region
>>   and HT regions.
>> - the arm-smmu reports the MSI window (arbitrarily located at
>>   0x8000000 and 1MB large).
>> Unsafe interrupt assignment is tested by enumerating all MSI irq
>> domains and checking MSI remapping is supported in the above hierarchy.
>> This check is done in case we detect the iommu translates MSI
>> (an IOMMU_RESV_MSI window exists). Otherwise the IRQ remapping
>> capability is checked at IOMMU level. Obviously this is a defensive
>> IRQ safety assessment: Assuming there are several MSI controllers
>> in the system and at least one does not implement IRQ remapping,
>> the assignment will be considered as unsafe (even if this controller
>> is not acessible from the assigned devices).
>> The series first patch stems from Robin's branch:
>> http://linux-arm.org/git?p=linux-rm.git;a=shortlog;h=refs/heads/iommu/misc
>> Best Regards
>> Eric
>> Git: complete series available at
>> https://github.com/eauger/linux/tree/v4.10-rc3-reserved-v8
> I tested the series on ThunderX with internal 10G VNIC and Intel IXGBE
> NIC. Please feel free to add my:
> Tested-by: Tomasz Nowicki <tomasz.nowicki at caviumnetworks.com>
Many thanks!

> Thanks,
> Tomasz
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