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[PATCH v2 0/2] spapr: Use vIOMMU translation for virtio by default

From: David Gibson
Subject: [PATCH v2 0/2] spapr: Use vIOMMU translation for virtio by default
Date: Thu, 13 Feb 2020 11:58:35 +1100

Upcoming Secure VM support for pSeries machines introduces some
complications for virtio, since the transfer buffers need to be
explicitly shared so that the hypervisor can access them.

While it's not strictly speaking dependent on it, the fact that virtio
devices bypass normal platform IOMMU translation complicates the issue
on the guest side.  Since there are some significan downsides to
bypassing the vIOMMU anyway, let's just disable that.

There's already a flag to do this in virtio, just turn it on by
default for forthcoming pseries machine types.

Any opinions on whether dropping support for the older guest kernels
is acceptable at this point?

Changes since v1:
 * Added information on which guest kernel versions will no longer
   work with these changes
 * Use Michael Tsirkin's suggested better way of handling the machine
   type change

David Gibson (2):
  spapr: Disable legacy virtio devices for pseries-5.0 and later
  spapr: Enable virtio iommu_platform=on by default

 hw/ppc/spapr.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)


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