With the additional of the OV5_HP_EVT option vector, we now have
certain functionality (namely, memory unplug) that checks at run-time
for whether or not the guest negotiated the option via CAS. Because
we don't currently migrate these negotiated values, we are unable
to unplug memory from a guest after it's been migrated until after
the guest is rebooted and CAS-negotiation is repeated.
This patch fixes this by adding CAS-negotiated options to the
migration stream. We do this using a subsection, since the
negotiated value of OV5_HP_EVT is the only option currently needed
to maintain proper functionality for a running guest.
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
PAPR guests advertise their capabilities to the platform by passing
an ibm,architecture-vec structure via an
ibm,client-architecture-support hcall as described by LoPAPR v11,
B.6.2.3. during early boot.
Using this information, the platform enables the capabilities it
supports, then encodes a subset of those enabled capabilities (the
5th option vector of the ibm,architecture-vec structure passed to
ibm,client-architecture-support) into the guest device tree via
"/chosen/ibm,architecture-vec-5".
The logical format of these these option vectors is a bit-vector,
where individual bits are addressed/documented based on the byte-wise
offset from the beginning of the bit-vector, followed by the bit-wise
index starting from the byte-wise offset. Thus the bits of each of
these bytes are stored in reverse order. Additionally, the first
byte of each option vector is encodes the length of the option vector,
so byte offsets begin at 1, and bit offset at 0.
This is not very intuitive for the purposes of mapping these bits to
a particular documented capability, so this patch introduces a set
of abstractions that encapsulate the work of parsing/encoding these
options vectors and testing for individual capabilities.
Cc: Bharata B Rao <bharata@linux.vnet.ibm.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
[dwg: Tweaked double-include protection to not trigger a checkpatch
false positive]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
