diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
index f5ee97de81..f3a639b972 100644
--- a/docs/formatdomain.html.in
+++ b/docs/formatdomain.html.in
@@ -9412,8 +9412,10 @@ qemu-kvm -net nic,model=? /dev/null
- the minimum label size is 128KiB,
- - the remaining size (total-size - label-size) will be aligned
- to 4KiB as default.
+ - the remaining size (total-size - label-size), also called guest
+ area, will be aligned to 4KiB as default. For pSeries guests, the
+ guest area will be aligned down to 256MiB, and the minimum size
+ of the guest area must be at least 256MiB.