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Re: [Qemu-devel] [PATCH 0/2] memory/intel_iommu: Generate error for inco
From: |
Alex Williamson |
Subject: |
Re: [Qemu-devel] [PATCH 0/2] memory/intel_iommu: Generate error for incompatible usage |
Date: |
Wed, 29 Jun 2016 09:56:01 -0600 |
On Wed, 29 Jun 2016 12:53:39 +0200
Paolo Bonzini <address@hidden> wrote:
> 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.
Hmm, I can't find any evidence of that and I'm not terribly comfortable
inferring an Acked-by where it is not explicitly given. Can you send
a formal sign-off or point me to where I can find the one you're
thinking of? Thanks,
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 1/2] memory: Add MemoryRegionIOMMUOps.notify_started/stopped callbacks, (continued)
- [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