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authorPeter Maydell <peter.maydell@linaro.org>2015-05-11 16:21:50 +0100
committerPeter Maydell <peter.maydell@linaro.org>2015-05-11 16:25:33 +0100
commit0403b0f539f40a21da60409b825b4653b273ab39 (patch)
treeef1edb203dc4595528c0f86c502df3a8d2931a2b /docs
parent266745cacb848d7cd0ae8889ae262e8718ace4d4 (diff)
parentbc1f7c4c915a7c727741c4d27a2795e1039eacd3 (diff)
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Merge remote-tracking branch 'remotes/mst/tags/for_upstream' into staging
pc, virtio enhancements Memory hot-unplug support for pc, MSI-X mapping update speedup for virtio-pci, misc refactorings and bugfixes. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> # gpg: Signature made Mon May 11 08:23:43 2015 BST using RSA key ID D28D5469 # gpg: Good signature from "Michael S. Tsirkin <mst@kernel.org>" # gpg: aka "Michael S. Tsirkin <mst@redhat.com>" * remotes/mst/tags/for_upstream: (28 commits) acpi: update expected files for memory unplug virtio-scsi: Move DEFINE_VIRTIO_SCSI_FEATURES to virtio-scsi virtio-net: Move DEFINE_VIRTIO_NET_FEATURES to virtio-net pci: Merge pci_nic_init() into pci_nic_init_nofail() acpi: add a missing backslash to the \_SB scope. qmp-event: add event notification for memory hot unplug error acpi: add hardware implementation for memory hot unplug acpi: fix "Memory device control fields" register acpi: extend aml_field() to support UpdateRule acpi, mem-hotplug: add unplug cb for memory device acpi, mem-hotplug: add unplug request cb for memory device acpi, mem-hotplug: add acpi_memory_slot_status() to get MemStatus docs: update documentation for memory hot unplug virtio: coding style tweak pci: remove hard-coded bar size in msix_init_exclusive_bar() virtio-pci: speedup MSI-X masking and unmasking virtio: introduce vector to virtqueues mapping virtio-ccw: using VIRTIO_NO_VECTOR instead of 0 for invalid virtqueue monitor: check return value of qemu_find_net_clients_except() monitor: replace the magic number 255 with MAX_QUEUE_NUM ... Conflicts: hw/s390x/s390-virtio-bus.c [PMM: fixed conflict in s390_virtio_scsi_properties and s390_virtio_net_properties arrays; since the result of the two conflicting patches is to empty the property arrays completely, the conflict resolution is to remove them entirely.] Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'docs')
-rw-r--r--docs/memory-hotplug.txt23
-rw-r--r--docs/qmp/qmp-events.txt17
-rw-r--r--docs/specs/acpi_mem_hotplug.txt58
3 files changed, 91 insertions, 7 deletions
diff --git a/docs/memory-hotplug.txt b/docs/memory-hotplug.txt
index f70571d..56bdd0a 100644
--- a/docs/memory-hotplug.txt
+++ b/docs/memory-hotplug.txt
@@ -4,9 +4,7 @@ QEMU memory hotplug
This document explains how to use the memory hotplug feature in QEMU,
which is present since v2.1.0.
-Please, note that memory hotunplug is not supported yet. This means
-that you're able to add memory, but you're not able to remove it.
-Also, proper guest support is required for memory hotplug to work.
+Guest support is required for memory hotplug to work.
Basic RAM hotplug
-----------------
@@ -74,3 +72,22 @@ comes from regular RAM, 1GB is a 1GB hugepage page and 256MB is from
-device pc-dimm,id=dimm1,memdev=mem1 \
-object memory-backend-file,id=mem2,size=256M,mem-path=/mnt/hugepages-2MB \
-device pc-dimm,id=dimm2,memdev=mem2
+
+
+RAM hot-unplug
+---------------
+
+In order to be able to hot unplug pc-dimm device, QEMU has to be told the ids
+of pc-dimm device and memory backend object. The ids were assigned when you hot
+plugged memory.
+
+Two monitor commands are used to hot unplug memory:
+
+ - "device_del": deletes a front-end pc-dimm device
+ - "object_del": deletes a memory backend object
+
+For example, assuming that the pc-dimm device with id "dimm1" exists, and its memory
+backend is "mem1", the following commands tries to remove it.
+
+ (qemu) device_del dimm1
+ (qemu) object_del mem1
diff --git a/docs/qmp/qmp-events.txt b/docs/qmp/qmp-events.txt
index 64ba46c..6dc2cca 100644
--- a/docs/qmp/qmp-events.txt
+++ b/docs/qmp/qmp-events.txt
@@ -232,6 +232,23 @@ Example:
{ "event": "GUEST_PANICKED",
"data": { "action": "pause" } }
+MEM_HOT_UNPLUG_ERROR
+--------------------
+Emitted when memory hot unplug error occurs.
+
+Data:
+
+- "device": device name (json-string)
+- "msg": Informative message (e.g., reason for the error) (json-string)
+
+Example:
+
+{ "event": "MEM_HOT_UNPLUG_ERROR"
+ "data": { "device": "dimm1",
+ "msg": "acpi: device unplug for unsupported device"
+ },
+ "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }
+
NIC_RX_FILTER_CHANGED
---------------------
diff --git a/docs/specs/acpi_mem_hotplug.txt b/docs/specs/acpi_mem_hotplug.txt
index 1290994..3df3620 100644
--- a/docs/specs/acpi_mem_hotplug.txt
+++ b/docs/specs/acpi_mem_hotplug.txt
@@ -2,7 +2,7 @@ QEMU<->ACPI BIOS memory hotplug interface
--------------------------------------
ACPI BIOS GPE.3 handler is dedicated for notifying OS about memory hot-add
-events.
+and hot-remove events.
Memory hot-plug interface (IO port 0xa00-0xa17, 1-4 byte access):
---------------------------------------------------------------
@@ -19,7 +19,9 @@ Memory hot-plug interface (IO port 0xa00-0xa17, 1-4 byte access):
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
+ 2: Device remove event, used to distinguish device for which
+ no device eject request to OSPM was issued.
+ 3-7: reserved and should be ignored by OSPM
[0x15-0x17] reserved
write access:
@@ -31,14 +33,62 @@ Memory hot-plug interface (IO port 0xa00-0xa17, 1-4 byte access):
[0xc-0x13] reserved, writes into it are ignored
[0x14] Memory device control fields
bits:
- 0: reserved, OSPM must clear it before writing to register
+ 0: reserved, OSPM must clear it before writing to register.
+ Due to BUG in versions prior 2.4 that field isn't cleared
+ when other fields are written. Keep it reserved and don't
+ try to reuse it.
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
+ 2: if set to 1 clears device remove event, set by OSPM
+ after it has emitted device eject request for the
+ selected memory device
+ 3: if set to 1 initiates device eject, set by OSPM when it
+ triggers memory device removal and calls _EJ0 method
+ 4-7: 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          |                     
+ +------------------+              |                   |                     
+                                   +-------------------+