On Mon, Oct 17, 2016 at 10:07:36AM -0600, Alex Williamson wrote: > On Mon, 17 Oct 2016 18:44:21 +0300 > "Aviv B.D" <bd.a...@gmail.com> wrote: > > > From: "Aviv Ben-David" <bd.a...@gmail.com> > > > > * Advertize Cache Mode capability in iommu cap register. > > This capability is controlled by "cache-mode" property of intel-iommu > > device. > > To enable this option call QEMU with "-device > > intel-iommu,cache-mode=true". > > > > * On page cache invalidation in intel vIOMMU, check if the domain belong to > > registered notifier, and notify accordingly. > > > > Currently this patch still doesn't enabling VFIO devices support with > > vIOMMU > > present. Current problems: > > * vfio_iommu_map_notify is not aware about memory range belong to specific > > VFIOGuestIOMMU. > > Could you elaborate on why this is an issue? > > > * memory_region_iommu_replay hangs QEMU on start up while it itterate over > > 64bit address space. Commenting out the call to this function enables > > workable VFIO device while vIOMMU present. > > This has been discussed previously, it would be incorrect for vfio not > to call the replay function. The solution is to add an iommu driver > callback to efficiently walk the mappings within a MemoryRegion.
Right, replay is a bit of a hack. There are a couple of other
approaches that might be adequate without a new callback:
- Make the VFIOGuestIOMMU aware of the guest address range mapped
by the vIOMMU. Intel currently advertises that as a full 64-bit
address space, but I bet that's not actually true in practice.
- Have the IOMMU MR advertise a (minimum) page size for vIOMMU
mappings. That may let you stpe through the range with greater
strides
> Thanks,
>
> Alex
>
> > Changes from v1 to v2:
> > * remove assumption that the cache do not clears
> > * fix lockup on high load.
> >
> > Changes from v2 to v3:
> > * remove debug leftovers
> > * split to sepearate commits
> > * change is_write to flags in vtd_do_iommu_translate, add IOMMU_NO_FAIL
> > to suppress error propagating to guest.
> >
> > Changes from v3 to v4:
> > * Add property to intel_iommu device to control the CM capability,
> > default to False.
> > * Use s->iommu_ops.notify_flag_changed to register notifiers.
> >
> > Changes from v4 to v4 RESEND:
> > * Fix codding style pointed by checkpatch.pl script.
> >
> > Aviv Ben-David (3):
> > IOMMU: add option to enable VTD_CAP_CM to vIOMMU capility exposoed to
> > guest
> > IOMMU: change iommu_op->translate's is_write to flags, add support to
> > NO_FAIL flag mode
> > IOMMU: enable intel_iommu map and unmap notifiers
> >
> > exec.c | 3 +-
> > hw/i386/amd_iommu.c | 4 +-
> > hw/i386/intel_iommu.c | 175
> > +++++++++++++++++++++++++++++++++--------
> > hw/i386/intel_iommu_internal.h | 3 +
> > include/exec/memory.h | 6 +-
> > include/hw/i386/intel_iommu.h | 11 +++
> > memory.c | 3 +-
> > 7 files changed, 168 insertions(+), 37 deletions(-)
> >
>
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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