Only adding cpus is supports at the moment, removal
will come next.
When new cpus are configured, the machine description is
updated. When we get the configure request we pass in a
cpu mask of to-be-added cpus to the mdesc CPU node parser
so it only fetches information for those cpus. That code
also proceeds to update the SMT/multi-core scheduling bitmaps.
cpu_up() does all the work and we return the status back
over the DS channel.
CPUs via dr-cpu need to be booted straight out of the
hypervisor, and this requires:
1) A new trampoline mechanism. CPUs are booted straight
out of the hypervisor with MMU disabled and running in
physical addresses with no mappings installed in the TLB.
The new hvtramp.S code sets up the critical cpu state,
installs the locked TLB mappings for the kernel, and
turns the MMU on. It then proceeds to follow the logic
of the existing trampoline.S SMP cpu bringup code.
2) All calls into OBP have to be disallowed when domaining
is enabled. Since cpus boot straight into the kernel from
the hypervisor, OBP has no state about that cpu and therefore
cannot handle being invoked on that cpu.
Luckily it's only a handful of interfaces which can be called
after the OBP device tree is obtained. For example, rebooting,
halting, powering-off, and setting options node variables.
CPU removal support will require some infrastructure changes
here. Namely we'll have to process the requests via a true
kernel thread instead of in a workqueue. workqueues run on
a per-cpu thread, but when unconfiguring we might need to
force the thread to execute on another cpu if the current cpu
is the one being removed. Removal of a cpu also causes the kernel
to destroy that cpu's workqueue running thread.
Another issue on removal is that we may have interrupts still
pointing to the cpu-to-be-removed. So new code will be needed
to walk the active INO list and retarget those cpus as-needed.
Signed-off-by: David S. Miller <davem@davemloft.net>
There is a special domain services capability for setting
variables in the OBP options node. Guests don't have permanent
store for the OBP variables like a normal system, so they are
instead maintained in the LDOM control node or in the SC.
Signed-off-by: David S. Miller <davem@davemloft.net>
All of the interrupts say "LDX RX" and "LDX TX" currently
which is next to useless. Put a device specific prefix
before "RX" and "TX" instead which makes it much more
useful.
Signed-off-by: David S. Miller <davem@davemloft.net>
1) LDC_MODE_RELIABLE is deprecated an unused by anything, plus
it and LDC_MODE_STREAM were mis-numbered.
2) read_stream() should try to read as much as possible into
the per-LDC stream buffer area, so do not trim the read_nonraw()
length by the caller's size parameter.
3) Send data ACKs when necessary in read_nonraw().
4) In read_nonraw() when we get a pure ACK, advance the RX head
unconditionally past it.
5) Provide the ACKID field in the ldcdgb() packet dump in read_nonraw().
This helps debugging stream mode LDC channel problems.
6) Decrease verbosity of rx_data_wait() so that it is more useful.
A debugging message each loop iteration is too much.
7) In process_data_ack() stop the loop checking when we hit lp->tx_tail
not lp->tx_head.
8) Set the seqid field properly in send_data_nack().
Signed-off-by: David S. Miller <davem@davemloft.net>
Virtual devices on Sun Logical Domains are built on top
of a virtual channel framework. This, with help of hypervisor
interfaces, provides a link layer protocol with basic
handshaking over which virtual device clients and servers
communicate.
Built on top of this is a VIO device protocol which has it's
own handshaking and message types. At this layer attributes
are exchanged (disk size, network device addresses, etc.)
descriptor rings are registered, and data transfers are
triggers and replied to.
Signed-off-by: David S. Miller <davem@davemloft.net>
