Re: [Qemu-devel] [V11 1/4] hw/i386: Introduce AMD IOMMU

[Jan Kiszka <jan.kiszka@web.de>]

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On 2016-06-07 22:36, Alex Williamson wrote:
> On Sun, 22 May 2016 13:21:51 +0300
> David Kiarie <davidkiarie4@gmail.com> wrote:
> 
>> Add AMD IOMMU emulaton to Qemu in addition to Intel IOMMU
>> The IOMMU does basic translation, error checking and has a
>> minimal IOTLB implementation. This IOMMU bypassed the need
>> for target aborts by responding with IOMMU_NONE access rights
>> and exempts the region 0xfee00000-0xfeefffff from translation
>> as it is the q35 interrupt region. We also advertise features
>> that are not yet implemented to please the Linux IOMMU driver.
>>
>> IOTLB aims at implementing commands on real IOMMUs which is
>> essential for debugging and may not offer any performance
>> benefits
>>
>> Signed-off-by: David Kiarie <davidkiarie4@gmail.com>
>> ---
>>  hw/i386/Makefile.objs |    1 +
>>  hw/i386/amd_iommu.c   | 1401 +++++++++++++++++++++++++++++++++++++++++++++++++
>>  hw/i386/amd_iommu.h   |  340 ++++++++++++
>>  include/hw/pci/pci.h  |    2 +
>>  4 files changed, 1744 insertions(+)
>>  create mode 100644 hw/i386/amd_iommu.c
>>  create mode 100644 hw/i386/amd_iommu.h
> 
> I don't see any callouts to memory_region_notify_iommu() here, so this
> won't yet support assigned devices.  Do you have any plans to add that
> support?  Thanks,

One after the other: correct emulation of all key features is the
primary goal, adding support for assigned devices a bonus. However, it's
not a simple one as we will probably need shadow page tables. So GSoC is
likely not long enough for this.

Jan



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