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Re: [Qemu-devel] [PATCH 0/2] memory/intel_iommu: Generate error for inco
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH 0/2] memory/intel_iommu: Generate error for incompatible usage |
Date: |
Wed, 29 Jun 2016 12:53:39 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 |
On 28/06/2016 16:49, Alex Williamson wrote:
> Paolo & Michael,
>
> Any comments on this series? I think we need Paolo's ack for the memory
> changes and either of your ack for hw/i386/. I'm happy to pull this
> through my tree with your approval though. Thanks,
I think I already acked the callbacks, in any case the patches look good.
Paolo
> Alex
>
> On Wed, 15 Jun 2016 09:56:03 -0600
> Alex Williamson <address@hidden> wrote:
>
>> VT-d emulation is currently incompatible with device assignment due
>> to intel_iommu's lack of support for memory_region_notify_iommu().
>> Alexey has proposed a nice addition to the MemoryRegionIOMMUOps
>> structure that adds callbacks when the first iommu notifier is
>> registered and the last is removed. For POWER this will allow them
>> to switch the view of the iommu depending on whether anyone in
>> userspace is watching. For VT-d I expect that eventually we'll use
>> these callbacks to enable and disable code paths so that we avoid
>> notifier overhead when there are no registered notifiy-ees. For now,
>> we don't support calling memory_region_notify_iommu(), so this
>> signals an incompatible hardware configuration. If we choose to make
>> CM=0 a user selectable option, something like this might continue to
>> be useful if we only support notifies via invalidations rather than
>> full VT-d data structure shadowing.
>>
>> Even though we're currently working on enabling users like vfio-pci
>> with VT-d, I believe this is correct for the current state of things.
>> We might even want to consider this stable for v2.6.x so that
>> downstreams pick it up to avoid incompatible configurations.
>>
>> Alexey, I hope I'm not stepping on your toes by extracting this
>> from your latest patch series. Please let us know whether you
>> approve. Thanks,
>>
>> Alex
>>
>> ---
>>
>> Alex Williamson (1):
>> intel_iommu: Throw hw_error on notify_started
>>
>> Alexey Kardashevskiy (1):
>> memory: Add MemoryRegionIOMMUOps.notify_started/stopped callbacks
>>
>>
>> hw/i386/intel_iommu.c | 12 ++++++++++++
>> hw/vfio/common.c | 5 +++--
>> include/exec/memory.h | 8 +++++++-
>> memory.c | 10 +++++++++-
>> 4 files changed, 31 insertions(+), 4 deletions(-)
>
- [Qemu-devel] [PATCH 0/2] memory/intel_iommu: Generate error for incompatible usage, Alex Williamson, 2016/06/15
- [Qemu-devel] [PATCH 1/2] memory: Add MemoryRegionIOMMUOps.notify_started/stopped callbacks, Alex Williamson, 2016/06/15
- [Qemu-devel] [PATCH 2/2] intel_iommu: Throw hw_error on notify_started, Alex Williamson, 2016/06/15
- Re: [Qemu-devel] [PATCH 0/2] memory/intel_iommu: Generate error for incompatible usage, Alexey Kardashevskiy, 2016/06/15
- Re: [Qemu-devel] [PATCH 0/2] memory/intel_iommu: Generate error for incompatible usage, Peter Xu, 2016/06/15
- Re: [Qemu-devel] [PATCH 0/2] memory/intel_iommu: Generate error for incompatible usage, Alex Williamson, 2016/06/28
- Re: [Qemu-devel] [PATCH 0/2] memory/intel_iommu: Generate error for incompatible usage,
Paolo Bonzini <=