Previously to read/write a GPA, we at first try to pin the GFN it belongs
to, then translate the pinned PFN to a kernel HVA, then read/write it.
This is however not necessary. A GFN should be pinned IFF it would be
accessed by peripheral devices (DMA), not by CPU. This patch changes
the read/write method to KVM API, which will leverage userspace HVA
and copy_{from|to}_usr instead.
Signed-off-by: NJike Song <jike.song@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

Signed-off-by: NJike Song <jike.song@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

Instead of partially depending on vfio pin/unpin pages interface if
mdev is available, which would result in failure if vfio is not
on. But replace with a wrapper which need to be fixed till mdev
support got fully merged.

Cc: Jike Song <jike.song@intel.com>
Cc: Xiaoguang Chen <xiaoguang.chen@intel.com>
Reviewed-by: NXiaoguang Chen <Xiaoguang.chen@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>

KVMGT is the MPT implementation based on VFIO/KVM. It provides
a kvmgt_mpt ops to gvt for vGPU access mediation, e.g. to
mediate and emulate the MMIO accesses, to inject interrupts
to vGPU user, to intercept the GTT writing and replace it with
DMA-able address, to write-protect guest PPGTT table for
shadowing synchronization, etc. This patch provides the MPT
implementation for GVT, not yet functional due to theabsence
of mdev.

It's built as kvmgt.ko, depends on vfio.ko, kvm.ko and mdev.ko,
and being required by i915.ko. To not introduce hard dependency
in i915.ko, we used indirect symbol reference. But that means
users have to include kvmgt.ko into init ramdisk if their
i915.ko is included.
Signed-off-by: NKevin Tian <kevin.tian@intel.com>
Signed-off-by: NXiaoguang Chen <xiaoguang.chen@intel.com>
Signed-off-by: NJike Song <jike.song@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>