add ivshmem documentation

[pve-docs.git] / qm.adoc

diff --git a/qm.adoc b/qm.adoc
index a15e0fe3cc99f83623ebdc299edbacbe3436bf09..77fec9871b5927444f439f035ed4065e1bcc24e0 100644 (file)
--- a/qm.adoc
+++ b/qm.adoc
@@ -437,7 +437,7 @@ will allow proper distribution of the VM resources on the host system.
 This option is also required to hot-plug cores or RAM in a VM.
 
 If the NUMA option is used, it is recommended to set the number of sockets to
-the number of sockets of the host system.
+the number of nodes of the host system.
 
 vCPU hot-plug
 ^^^^^^^^^^^^^
@@ -703,6 +703,25 @@ you need to set the client resolution in the OVMF menu(which you can reach
 with a press of the ESC button during boot), or you have to choose
 SPICE as the display type.
 
+[[qm_ivshmem]]
+Inter-VM shared memory
+~~~~~~~~~~~~~~~~~~~~~~
+
+You can add a Inter-VM shared memory device (`ivshmem`) to be able to
+share memory between the host and a guest, or between multiple guests.
+
+To add such a device, you can use `qm`:
+
+  qm set <vmid> -ivshmem size=32,name=foo
+
+Where the size is in MiB. The file will be located under
+`/dev/shm/pve-shm-$name` (the default name is the vmid).
+
+A usecase for such a device is Looking Glass
+footnote:[Looking Glass: https://looking-glass.hostfission.com/]
+which enables high performance, low-latency display mirroring between
+host and guest.
+
 [[qm_startup_and_shutdown]]
 Automatic Start and Shutdown of Virtual Machines
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -829,7 +848,7 @@ migrate a VM to a totally different storage. You can also change the
 disk image *Format* if the storage driver supports several formats.
 +
 
-NOTE: A full clone need to read and copy all VM image data. This is
+NOTE: A full clone needs to read and copy all VM image data. This is
 usually much slower than creating a linked clone.
 +
 
@@ -840,7 +859,7 @@ never includes any additional snapshots from the original VM.
 
 Linked Clone::
 
-Modern storage drivers supports a way to generate fast linked
+Modern storage drivers support a way to generate fast linked
 clones. Such a clone is a writable copy whose initial contents are the
 same as the original data. Creating a linked clone is nearly
 instantaneous, and initially consumes no additional space.
@@ -857,8 +876,8 @@ can convert any VM into a read-only <<qm_templates, Template>>). Such
 templates can later be used to create linked clones efficiently.
 +
 
-NOTE: You cannot delete the original template while linked clones
-exists.
+NOTE: You cannot delete an original template while linked clones
+exist.
 +
 
 It is not possible to change the *Target storage* for linked clones,
@@ -869,7 +888,7 @@ The *Target node* option allows you to create the new VM on a
 different node. The only restriction is that the VM is on shared
 storage, and that storage is also available on the target node.
 
-To avoid resource conflicts, all network interface MAC addresses gets
+To avoid resource conflicts, all network interface MAC addresses get
 randomized, and we generate a new 'UUID' for the VM BIOS (smbios1)
 setting.
 
@@ -1030,6 +1049,16 @@ ifndef::wiki[]
 include::qm-pci-passthrough.adoc[]
 endif::wiki[]
 
+Hookscripts
+~~~~~~~~~~~
+
+You can add a hook script to VMs with the config property `hookscript`.
+
+ qm set 100 -hookscript local:snippets/hookscript.pl
+
+It will be called during various phases of the guests lifetime.
+For an example and documentation see the example script under
+`/usr/share/pve-docs/examples/guest-example-hookscript.pl`.
 
 Managing Virtual Machines with `qm`
 ------------------------------------