Usually, PAPR virtual IO devices use a virtual IOMMU mechanism, TCEs,
to mediate all DMA transfers. While this is necessary for some sorts of
operation, it can be complex to program and slow for others.
This patch implements a mechanism for bypassing TCE translation, treating
"IO" addresses as plain (guest) physical memory addresses. This has two
main uses:
* Simple, but 64-bit aware programs like firmwares can use the VIO devices
without the complexity of TCE setup.
* The guest OS can optionally use the TCE bypass to improve performance in
suitable situations.
The mechanism used is a per-device flag which disables TCE translation.
The flag is toggled with some (hypervisor-implemented) RTAS methods.
Signed-off-by: Ben Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
This patch implements the infrastructure and hypercalls necessary for the
PAPR specified CRQ (Command Request Queue) mechanism. This general
request queueing system is used by many of the PAPR virtual IO devices,
including the virtual scsi adapter.
Signed-off-by: Ben Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
This patch implements the necessary infrastructure and hypercalls for
sPAPR's TCE (Translation Control Entry) IOMMU mechanism. This is necessary
for all virtual IO devices which do DMA (i.e. nearly all of them).
Signed-off-by: Ben Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
This patch adds infrastructure to support interrupts from PAPR virtual IO
devices. This includes correctly advertising those interrupts in the
device tree, and implementing the H_VIO_SIGNAL hypercall, used to
enable and disable individual device interrupts.
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
This extends the "pseries" (PAPR) machine to include a virtual IO bus
supporting the PAPR defined hypercall based virtual IO mechanisms.
So far only one VIO device is provided, the vty / vterm, providing
a full console (polled only, for now).
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Ben Herrenschmidt