spapr: Support ibm,dynamic-reconfiguration-memory

Parse ibm,architecture.vec table obtained from the guest and enable
memory node configuration via ibm,dynamic-reconfiguration-memory if guest
supports it. This is in preparation to support memory hotplug for
sPAPR guests.

This changes the way memory node configuration is done. Currently all
memory nodes are built upfront. But after this patch, only memory@0 node
for RMA is built upfront. Guest kernel boots with just that and rest of
the memory nodes (via memory@XXX or ibm,dynamic-reconfiguration-memory)
are built when guest does ibm,client-architecture-support call.

Note: This patch needs a SLOF enhancement which is already part of
SLOF binary in QEMU.

Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

1 files changed, 48 insertions, 0 deletions

diff --git a/docs/specs/ppc-spapr-hotplug.txt b/docs/specs/ppc-spapr-hotplug.txt
index 46e07196bb..631b0cadae 100644
--- a/docs/specs/ppc-spapr-hotplug.txt
+++ b/docs/specs/ppc-spapr-hotplug.txt
@@ -302,4 +302,52 @@ consisting of <phys>, <size> and <maxcpus>.
 pseries guests use this property to note the maximum allowed CPUs for the
 guest.
 
+== ibm,dynamic-reconfiguration-memory ==
+
+ibm,dynamic-reconfiguration-memory is a device tree node that represents
+dynamically reconfigurable logical memory blocks (LMB). This node
+is generated only when the guest advertises the support for it via
+ibm,client-architecture-support call. Memory that is not dynamically
+reconfigurable is represented by /memory nodes. The properties of this
+node that are of interest to the sPAPR memory hotplug implementation
+in QEMU are described here.
+
+ibm,lmb-size
+
+This 64bit integer defines the size of each dynamically reconfigurable LMB.
+
+ibm,associativity-lookup-arrays
+
+This property defines a lookup array in which the NUMA associativity
+information for each LMB can be found. It is a property encoded array
+that begins with an integer M, the number of associativity lists followed
+by an integer N, the number of entries per associativity list and terminated
+by M associativity lists each of length N integers.
+
+This property provides the same information as given by ibm,associativity
+property in a /memory node. Each assigned LMB has an index value between
+0 and M-1 which is used as an index into this table to select which
+associativity list to use for the LMB. This index value for each LMB
+is defined in ibm,dynamic-memory property.
+
+ibm,dynamic-memory
+
+This property describes the dynamically reconfigurable memory. It is a
+property encoded array that has an integer N, the number of LMBs followed
+by N LMB list entires.
+
+Each LMB list entry consists of the following elements:
+
+- Logical address of the start of the LMB encoded as a 64bit integer. This
+  corresponds to reg property in /memory node.
+- DRC index of the LMB that corresponds to ibm,my-drc-index property
+  in a /memory node.
+- Four bytes reserved for expansion.
+- Associativity list index for the LMB that is used as an index into
+  ibm,associativity-lookup-arrays property described earlier. This
+  is used to retrieve the right associativity list to be used for this
+  LMB.
+- A 32bit flags word. The bit at bit position 0x00000008 defines whether
+  the LMB is assigned to the the partition as of boot time.
+
 [1] http://thread.gmane.org/gmane.linux.ports.ppc.embedded/75350/focus=106867