tree 7a9b10d619f34b9248ab10909449293b494275b5
parent 70bca53ffb811ea59dc090b3ca7825cf0bf346a7
author David Gibson <david@gibson.dropbear.id.au> 1319730991 +0000
committer Alexander Graf <agraf@suse.de> 1320001407 +0100

pseries: Allow writes to KVM accelerated TCE table

Sufficiently recent kernels include a KVM call to accelerate use of
PAPR TCE tables (IOMMU), which are used by PAPR virtual IO devices.
This involves qemu mapping the TCE table in from a kernel obtained fd,
which currently we do with PROT_READ only.  This is a hangover from
early (never released) versions of this kernel interface which only
permitted read-only mappings and required us to destroy and recreate
the table when we needed to clear it from qemu.

Now, the kernel permits read-write mappings, and we rely on this to
clear the table in spapr_vio_quiesce_one().  However, due to
insufficient testing, I forgot to update the actual mapping of the
table in kvmppc_create_spapr_tce() to add PROT_WRITE to the mmap().

This patch corrects the oversight.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>