Re: [Qemu-devel] [V9 0/4] AMD IOMMU

[Valentine Sinitsyn <valentine.sinitsyn@gmail.com>]

Hi everyone,

On 04.05.2016 12:05, David Kiarie wrote:
> On Wed, May 4, 2016 at 9:12 AM, Jan Kiszka <jan.kiszka@web.de> wrote:
>> On 2016-04-30 00:42, David Kiarie wrote:
>>> These series adds AMD IOMMU support to Qemu. It's currently in the 9th version.
>>>
>>> In this series I have (hopefully) addressed all the comments made in the previous version.
>>> I have also tested and successfully passed-through PCI device 'ac97' with more devices to be tested.
>>>
>>
>> I've done some basic testing with a Jailhouse setup and found it
>> working. The ACPI table is now properly parsed and the DMA remapping was
>> not disturbing the system after Jailhouse was activated.
>>
>> However, it was also still not intervening after I started to corrupt
>> the configuration, removed DMA target properties from most of the RAM or
>> dropped PCI devices.
Please also remember that unlisted devices go without translation. To 
"mute" the device, set V, TV, the DomainId, and zero everything else in 
the DTE.

>
> This means you're invalidating DTEs ?
>
>>
>> You are not dropping invalid remapping requests, are you? According to
>> the logs, you are detecting them at least:
>>
>> (amd-iommu)amd_iommu_get_dte: Device Table at 0x3b0d4000
>> (amd-iommu)amd_iommu_get_dte: Pte entry at 0x0 is invalid
>> (amd-iommu)amd_iommu_translate: devid: 00:02.0 gpa 0x32f39480 hpa 0x32f39000
>>
>> It's a bit hard to test right now if remapping is actually properly
>> working in all important cases if you do not reject invalid ones.
My understanding is that you should generate an IO_PAGE_FAULT event and 
drop the request. This doesn't apply to ATS, which is a bit trickier, 
but we don't address ATS in this patch series anyway, do we?

Valentine