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spapr: update spapr hotplug documentation

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This updates the existing documentation to reflect recent updates to
the hotplug event structure, which are in draft form but slated
for inclusion in PAPR/LoPAPR.

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This commit is contained in:
Michael Roth 2016-10-26 21:20:25 -05:00 committed by David Gibson
parent 6db246f93a
commit 9f992cca93
1 changed files with 46 additions and 9 deletions
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55
docs/specs/ppc-spapr-hotplug.txt
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@ -233,12 +233,27 @@ tools by host-level management such as an HMC. This level of management is not
applicable to PowerKVM, hence the reason for extending the notification
framework to support hotplug events.
Note that these events are not yet formally part of the PAPR+ specification,
but support for this format has already been implemented in DR-related
guest tools such as powerpc-utils/librtas, as well as kernel patches that have
been submitted to handle in-kernel processing of memory/cpu-related hotplug
events[1], and is planned for formal inclusion is PAPR+ specification. The
hotplug-specific payload is QEMU implemented as follows (with all values
The format for these EPOW-signalled events is described below under
"hotplug/unplug event structure". Note that these events are not
formally part of the PAPR+ specification, and have been superseded by a
newer format, also described below under "hotplug/unplug event structure",
and so are now deemed a "legacy" format. The formats are similar, but the
"modern" format contains additional fields/flags, which are denoted for the
purposes of this documentation with "#ifdef GUEST_SUPPORTS_MODERN" guards.
QEMU should assume support only for "legacy" fields/flags unless the guest
advertises support for the "modern" format via ibm,client-architecture-support
hcall by setting byte 5, bit 6 of it's ibm,architecture-vec-5 option vector
structure (as described by LoPAPR v11, B.6.2.3). As with "legacy" format events,
"modern" format events are surfaced to the guest via check-exception RTAS calls,
but use a dedicated event source to signal the guest. This event source is
advertised to the guest by the addition of a "hot-plug-events" node under
"/event-sources" node of the guest's device tree using the standard format
described in LoPAPR v11, B.6.12.1.
== hotplug/unplug event structure ==
The hotplug-specific payload in QEMU is implemented as follows (with all values
encoded in big-endian format):
struct rtas_event_log_v6_hp {
@ -263,14 +278,23 @@ struct rtas_event_log_v6_hp {
#define RTAS_LOG_V6_HP_ACTION_ADD 1
#define RTAS_LOG_V6_HP_ACTION_REMOVE 2
uint8_t hotplug_action; /* action (add/remove) */
#define RTAS_LOG_V6_HP_ID_DRC_NAME 1
#define RTAS_LOG_V6_HP_ID_DRC_INDEX 2
#define RTAS_LOG_V6_HP_ID_DRC_COUNT 3
#define RTAS_LOG_V6_HP_ID_DRC_NAME 1
#define RTAS_LOG_V6_HP_ID_DRC_INDEX 2
#define RTAS_LOG_V6_HP_ID_DRC_COUNT 3
#ifdef GUEST_SUPPORTS_MODERN
#define RTAS_LOG_V6_HP_ID_DRC_COUNT_INDEXED 4
#endif
uint8_t hotplug_identifier; /* type of the resource identifier,
* which serves as the discriminator
* for the 'drc' union field below
*/
#ifdef GUEST_SUPPORTS_MODERN
uint8_t capabilities; /* capability flags, currently unused
* by QEMU
*/
#else
uint8_t reserved;
#endif
union {
uint32_t index; /* DRC index of resource to take action
* on
@ -278,6 +302,19 @@ struct rtas_event_log_v6_hp {
uint32_t count; /* number of DR resources to take
* action on (guest chooses which)
*/
#ifdef GUEST_SUPPORTS_MODERN
struct {
uint32_t count; /* number of DR resources to take
* action on
*/
uint32_t index; /* DRC index of first resource to take
* action on. guest will take action
* on DRC index <index> through
* DRC index <index + count - 1> in
* sequential order
*/
} count_indexed;
#endif
char name[1]; /* string representing the name of the
* DRC to take action on
*/