Il 24/04/2014 02:16, Peter Crosthwaite ha scritto:
> On Thu, Apr 24, 2014 at 1:21 AM, Eric Auger <eric.au...@linaro.org> wrote:
>> On 04/17/2014 07:29 PM, Alvise Rigo wrote:
>>> These patches were born after trying the current work on device
>>> passthrough (see thread "[Qemu-devel] [RFC v2 0/6] KVM platform device
>>> passthrough") with a DMA330 and FastModels. This work want to be the
>>> starting point for dicussion on some aspects related to the next VFIO
>>> platform development:
>>>
>>> - [PATCH 1/4] Add a way to allocate memory region from a user pointer
>>> for devices, and not exclusively for RAM. This is useful to exclude
>>> the devices bound to VFIO from being DMA mapped by the VFIO memory
>>> listener.
>>>
>>> - [PATCH 2/4] Addition of the exec flag to the DMA mappings. This is
>>> mandatory only for the ARM SMMU: in its next version VFIO will be able
>>> to tell if the flag is supported.
>>>
>>> - [PATCH 3/4] Possibility to bind a wider class of devices. In
>>> particular the patch proposes a solution to enhance a bit the device
>>> tree nodes generation, allowing to specify more than one compatibility
>>> property (handy for AMBA devices).
>>
>> I Alvise,
>>
>> This improvement was indeed needed. Do you want me to integrate that one
>> on next RFC version or do you maintain it on your side?
>>
>
> I think its probably best taken as a squash to your series.
Agreed.
Regards,
alvise
>
> Regards,
> Peter
>
>> This was required by the DMA330
>>> that needs “arm,pl330”,”arm,primecell” as compatibility string,
>>> together with a clock source defined in the device tree. In the future
>>> VFIO will be able to tell if we are dealing with an AMBA device;
>>
>> Any idea of how you want to achieve this? Is it something that can be
>> generalized to other devices?
>>
>> before
>>> that, we have to rely on the compatibility string to state that.
>>
>>>
>>> - [PATCH 4/4] Another approach to handle the EOI, starting from the
>>> assumption that we know in advance the location of the interrupt clear
>>> register of the device. Testing the reference patches I was noticing
>>> that the EOI mechanism was disabling the interrupt three times,
>>> because the kernel driver was reading some registers in the timer
>>> window before actually clearing the interrupt.
>>
>>
>> can you elaborate on the last sentence and especially "EOI mechanism was
>> disabling the interrupt 3 times". I do not get what you mean here.
>>
>> Best Regards
>>
>> Eric
>>
>>> This is of course
>>> another workaround and not the definitive solution until we can rely
>>> on a proper callback from the VGIC (something that we will see in a
>>> future version of VFIO for platform devices).
>>>
>>> These patches are based on the QEMU branch mentioned in the original
>>> thread ("[Qemu-devel] [RFC v2 0/6] KVM platform device passthrough").
>>>
>>> Alvise Rigo (4):
>>> Allocate non-RAM MemoryRegion from user pointer
>>> Add EXEC_FLAG to VFIO DMA mappings
>>> Add AMBA devices support to VFIO
>>> MemoryRegion with EOI callbacks for VFIO Platform devices
>>>
>>> exec.c | 2 +-
>>> hw/arm/virt.c | 39 +++++++++--
>>> hw/vfio/common.c | 3 +
>>> hw/vfio/platform.c | 158
>>> ++++++++++++++++++++++++++++++++++++++++++---
>>> include/exec/memory.h | 16 +++++
>>> linux-headers/linux/vfio.h | 1 +
>>> memory.c | 14 ++++
>>> memory_mapping.c | 2 +-
>>> 8 files changed, 220 insertions(+), 15 deletions(-)
>>>
>>
>>
