Currently the pseries machine init code builds up an array, envs, of
CPUState pointers for all the cpus in the system. This is kind of
pointless, given the generic code already has a perfectly good linked list
of the cpus.
In addition, there are a number of places which assume that the cpu's
cpu_index field is equal to its index in this array. This is true in
practice, because cpu_index values are just assigned sequentially, but
it's conceptually incorrect and may not always be true.
Therefore, this patch abolishes the envs array, and explicitly uses the
generic cpu linked list and cpu_index values throughout.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>
Currently, the emulated pSeries machine requires the use of the
-kernel parameter in order to explicitly load a guest kernel. This
means booting from the virtual disk, cdrom or network is not possible.
This patch addresses this limitation by inserting a within-partition
firmware image (derived from the "SLOF" free Open Firmware project).
If -kernel is not specified, qemu will now load the SLOF image, which
has access to the qemu boot device list through the device tree, and
can boot from any of the usual virtual devices.
In order to support the new firmware, an extension to the emulated
machine/hypervisor is necessary. Unlike Linux, which expects
multi-CPU entry to be handled kexec() style, the SLOF firmware expects
only one CPU to be active at entry, and to use a hypervisor RTAS
method to enable the other CPUs one by one.
This patch also implements this 'start-cpu' method, so that SLOF can
start the secondary CPUs and marshal them into the kexec() holding
pattern ready for entry into the guest OS. Linux should, and in the
future might directly use the start-cpu method to enable initially
disabled CPUs, but for now it does require kexec() entry.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Shared-processor partitions are those where a CPU is time-sliced between
partitions, rather than being permanently dedicated to a single
partition. qemu emulated partitions, since they are just scheduled with
the qemu user process, behave mostly like shared processor partitions.
In order to better support shared processor partitions (splpar), PAPR
defines the "VPA" (Virtual Processor Area), a shared memory communication
channel between the hypervisor and partitions. There are also two
additional shared memory communication areas for specialized purposes
associated with the VPA.
A VPA is not essential for operating an splpar, though it can be necessary
for obtaining accurate performance measurements in the presence of
runtime partition switching.
Most importantly, however, the VPA is a prerequisite for PAPR's H_CEDE,
hypercall, which allows a partition OS to give up it's shared processor
timeslices to other partitions when idle.
This patch implements the VPA and H_CEDE hypercalls in qemu. We don't
implement any of the more advanced statistics which can be communicated
through the VPA. However, this is enough to make normal pSeries kernels
do an effective power-save idle on an emulated pSeries, significantly
reducing the host load of a qemu emulated pSeries running an idle guest OS.
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 Virtual SCSI interface. This is the normal method
for providing (virtual) disks to PAPR partitions.
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 PAPR specified Inter Virtual Machine Logical
LAN; that is the virtual hardware used by the Linux ibmveth driver.
Signed-off-by: Paul Mackerras <paulus@samba.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>
Now that we have implemented the PAPR "xics" virtualized interrupt
controller, we can add interrupts in PAPR VIO devices. This patch adds
interrupt support to the PAPR virtual tty/console device.
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>
PAPR defines an interrupt control architecture which is logically divided
into ICS (Interrupt Control Presentation, each unit is responsible for
presenting interrupts to a particular "interrupt server", i.e. CPU) and
ICS (Interrupt Control Source, each unit responsible for one or more
hardware interrupts as numbered globally across the system). All PAPR
virtual IO devices expect to deliver interrupts via this mechanism. In
Linux, this interrupt controller system is handled by the "xics" driver.
On pSeries systems, access to the interrupt controller is virtualized via
hypercalls and RTAS methods. However, the virtualized interface is very
similar to the underlying interrupt controller hardware, and similar PICs
exist un-virtualized in some other systems.
This patch implements both the ICP and ICS sides of the PAPR interrupt
controller. For now, only the hypercall virtualized interface is provided,
however it would be relatively straightforward to graft an emulated
register interface onto the underlying interrupt logic if we want to add
a machine with a hardware ICS/ICP system in the future.
There are some limitations in this implementation: it is assumed for now
that only one instance of the ICS exists, although a full xics system can
have several, each responsible for a different group of hardware irqs.
ICP/ICS can handle both level-sensitve (LSI) and message signalled (MSI)
interrupt inputs. For now, this implementation supports only MSI
interrupts, since that is used by PAPR virtual IO devices.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
This patch adds several small utility hypercalls and RTAS methods to
the pSeries platform emulation. Specifically:
* 'display-character' rtas call
This just prints a character to the console, it's occasionally used
for early debug of the OS. The support includes a hack to make this
RTAS call respond on the normal token value present on real hardware,
since some early debugging tools just assume this value without
checking the device tree.
* 'get-time-of-day' rtas call
This one just takes the host real time, converts to the PAPR described
format and returns it to the guest.
* 'power-off' rtas call
This one shuts down the emulated system.
* H_DABR hypercall
On pSeries, the DABR debug register is usually a hypervisor resource
and virtualized through this hypercall. If the hypercall is not
present, Linux will under some circumstances attempt to manipulate the
DABR directly which will fail on this emulated machine.
This stub implementation is enough to stop that behaviour, although it
doesn't actually implement the requested DABR operations as yet.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
On pSeries machines, operating systems can instantiate "RTAS" (Run-Time
Abstraction Services), a runtime component of the firmware which implements
a number of low-level, infrequently used operations. On logical partitions
under a hypervisor, many of the RTAS functions require hypervisor
privilege. For simplicity, therefore, hypervisor systems typically
implement the in-partition RTAS as just a tiny wrapper around a hypercall
which actually implements the various RTAS functions.
This patch implements such a hypercall based RTAS for our emulated pSeries
machine. A tiny in-partition "firmware" calls a new hypercall, which
looks up available RTAS services in a table.
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
On pSeries logical partitions, excepting the old POWER4-style full system
partitions, the guest does not have direct access to the hardware page
table. Instead, the pagetable exists in hypervisor memory, and the guest
must manipulate it with hypercalls.
However, our current pSeries emulation more closely resembles the old
style where the guest must set up and handle the pagetables itself. This
patch converts it to act like a modern partition.
This involves two things: first, the hash translation path is modified to
permit the has table to be stored externally to the emulated machine's
RAM. The pSeries machine init code configures the CPUs to use this mode.
Secondly, we emulate the PAPR hypercalls for manipulating the external
hashed page table.
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>
This patch adds a "pseries" machine to qemu. This aims to emulate a
logical partition on an IBM pSeries machine, compliant to the
"PowerPC Architecture Platform Requirements" (PAPR) document.
This initial version is quite limited, it implements a basic machine
and PAPR hypercall emulation. So far only one hypercall is present -
H_PUT_TERM_CHAR - so that a (write-only) console is available.
Multiple CPUs are permitted, with SMP entry handled kexec() style.
The machine so far more resembles an old POWER4 style "full system
partition" rather than a modern LPAR, in that the guest manages the
page tables directly, rather than via hypercalls.
The machine requires qemu to be configured with --enable-fdt. The
machine can (so far) only be booted with -kernel - i.e. no partition
firmware is provided.
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
