mirror of
https://github.com/Motorhead1991/qemu.git
synced 2025-08-04 16:23:55 -06:00
4fccb4834d
Add specification about how to use memory hot unplug, and add a flow diagram to explain memory hot unplug process. Reviewed-by: Igor Mammedov <imammedo@redhat.com> Signed-off-by: Zhu Guihua <zhugh.fnst@cn.fujitsu.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
84 lines
8.3 KiB
Text
84 lines
8.3 KiB
Text
QEMU<->ACPI BIOS memory hotplug interface
|
||
--------------------------------------
|
||
|
||
ACPI BIOS GPE.3 handler is dedicated for notifying OS about memory hot-add
|
||
and hot-remove events.
|
||
|
||
Memory hot-plug interface (IO port 0xa00-0xa17, 1-4 byte access):
|
||
---------------------------------------------------------------
|
||
0xa00:
|
||
read access:
|
||
[0x0-0x3] Lo part of memory device phys address
|
||
[0x4-0x7] Hi part of memory device phys address
|
||
[0x8-0xb] Lo part of memory device size in bytes
|
||
[0xc-0xf] Hi part of memory device size in bytes
|
||
[0x10-0x13] Memory device proximity domain
|
||
[0x14] Memory device status fields
|
||
bits:
|
||
0: Device is enabled and may be used by guest
|
||
1: Device insert event, used to distinguish device for which
|
||
no device check event to OSPM was issued.
|
||
It's valid only when bit 1 is set.
|
||
2-7: reserved and should be ignored by OSPM
|
||
[0x15-0x17] reserved
|
||
|
||
write access:
|
||
[0x0-0x3] Memory device slot selector, selects active memory device.
|
||
All following accesses to other registers in 0xa00-0xa17
|
||
region will read/store data from/to selected memory device.
|
||
[0x4-0x7] OST event code reported by OSPM
|
||
[0x8-0xb] OST status code reported by OSPM
|
||
[0xc-0x13] reserved, writes into it are ignored
|
||
[0x14] Memory device control fields
|
||
bits:
|
||
0: reserved, OSPM must clear it before writing to register
|
||
1: if set to 1 clears device insert event, set by OSPM
|
||
after it has emitted device check event for the
|
||
selected memory device
|
||
2-7: reserved, OSPM must clear them before writing to register
|
||
|
||
Selecting memory device slot beyond present range has no effect on platform:
|
||
- write accesses to memory hot-plug registers not documented above are
|
||
ignored
|
||
- read accesses to memory hot-plug registers not documented above return
|
||
all bits set to 1.
|
||
|
||
Memory hot remove process diagram:
|
||
----------------------------------
|
||
+-------------+ +-----------------------+ +------------------+
|
||
| 1. QEMU | | 2. QEMU | |3. QEMU |
|
||
| device_del +---->+ device unplug request +----->+Send SCI to guest,|
|
||
| | | cb | |return control to |
|
||
+-------------+ +-----------------------+ |management |
|
||
+------------------+
|
||
|
||
+---------------------------------------------------------------------+
|
||
|
||
+---------------------+ +-------------------------+
|
||
| OSPM: | remove event | OSPM: |
|
||
| send Eject Request, | | Scan memory devices |
|
||
| clear remove event +<-------------+ for event flags |
|
||
| | | |
|
||
+---------------------+ +-------------------------+
|
||
|
|
||
|
|
||
+---------v--------+ +-----------------------+
|
||
| Guest OS: | success | OSPM: |
|
||
| process Ejection +----------->+ Execute _EJ0 method, |
|
||
| request | | set eject bit in flags|
|
||
+------------------+ +-----------------------+
|
||
|failure |
|
||
v v
|
||
+------------------------+ +-----------------------+
|
||
| OSPM: | | QEMU: |
|
||
| set OST event & status | | call device unplug cb |
|
||
| fields | | |
|
||
+------------------------+ +-----------------------+
|
||
| |
|
||
v v
|
||
+------------------+ +-------------------+
|
||
|QEMU: | |QEMU: |
|
||
|Send OST QMP event| |Send device deleted|
|
||
| | |QMP event |
|
||
+------------------+ | |
|
||
+-------------------+
|