diff --git a/virt/vm.md b/virt/vm.md
index 5593ca6..323d612 100644
--- a/virt/vm.md
+++ b/virt/vm.md
@@ -2,7 +2,7 @@
 title: Machine definition
 description: Virtual machine hardware
 published: true
-date: 2025-06-03T12:34:13.773Z
+date: 2025-06-03T18:37:54.590Z
 tags: 
 editor: markdown
 dateCreated: 2025-06-01T17:37:29.262Z
@@ -209,3 +209,28 @@ For Windows NT guests, more features are enabled:
   [...]
 </domain>
 ```
+
+## The clock
+
+In most case, the guest clock derives from the host clock. 
+
+In the following example, the hardware clock uses [UTC](https://en.wikipedia.org/wiki/Coordinated_Universal_Time) and has several timers
+
+```
+<domain type='kvm'>
+[...]
+  <clock offset='utc'>
+    <timer name='kvmclock' tickpolicy='catchup'/>
+  </clock>
+[...]
+</domain>
+```
+
+The *KVM clock* timer has a catchup policy, which means that a paused guest whose clock will is frozen will eventually catch up with the host clock when the guest is resumed.
+
+> On non realtime kernel, the KVM clock is updated every 5 minutes for all vCPUs, which may not be enough for accurate timekeeping. For that reason, "[Red Hat recommends running NTP in the virtual machine if accurate timekeeping is required](https://access.redhat.com/solutions/27865)"
+{.is-info}
+
+- [Timekeeping Virtualization for X86-Based Architectures](https://docs.kernel.org/virt/kvm/x86/timekeeping.html)
+- SUSE documentation: [VM Guest clock settings](https://documentation.suse.com/sles/15-SP3/html/SLES-all/sec-kvm-managing-clock.html#)
+- [Best practices for accurate timekeeping for Red Hat Enterprise Linux running on Red Hat Virtualization](https://access.redhat.com/solutions/27865)
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