1 files changed, 30 insertions, 9 deletions

diff --git a/qemu-deprecated.texi b/qemu-deprecated.texi
index dfb278a377..674cc3fdf8 100644
--- a/qemu-deprecated.texi
+++ b/qemu-deprecated.texi
@@ -37,12 +37,6 @@ would automatically enable USB support on the machine type.
 If using the new syntax, USB support must be explicitly
 enabled via the ``-machine usb=on'' argument.
 
-@subsection -no-frame (since 2.12.0)
-
-The @code{--no-frame} argument works with SDL 1.2 only. The other user
-interfaces never implemented this in the first place. So this will be
-removed together with SDL 1.2 support.
-
 @subsection -virtioconsole (since 3.0.0)
 
 Option @option{-virtioconsole} has been replaced by
@@ -161,8 +155,35 @@ The above, converted to the current supported format:
 
 @code{json:@{"file.driver":"rbd", "file.pool":"rbd", "file.image":"name"@}}
 
-@subsection vio-spapr-device device options
+@section Related binaries
+
+@subsection qemu-nbd --partition (since 4.0.0)
+
+The ``qemu-nbd --partition $digit'' code (also spelled @option{-P})
+can only handle MBR partitions, and has never correctly handled
+logical partitions beyond partition 5.  If you know the offset and
+length of the partition (perhaps by using @code{sfdisk} within the
+guest), you can achieve the effect of exporting just that subset of
+the disk by use of the @option{--image-opts} option with a raw
+blockdev using the @code{offset} and @code{size} parameters layered on
+top of any other existing blockdev. For example, if partition 1 is
+100MiB long starting at 1MiB, the old command:
+
+@code{qemu-nbd -t -P 1 -f qcow2 file.qcow2}
+
+can be rewritten as:
+
+@code{qemu-nbd -t --image-opts driver=raw,offset=1M,size=100M,file.driver=qcow2,file.backing.driver=file,file.backing.filename=file.qcow2}
+
+Alternatively, the @code{nbdkit} project provides a more powerful
+partition filter on top of its nbd plugin, which can be used to select
+an arbitrary MBR or GPT partition on top of any other full-image NBD
+export.  Using this to rewrite the above example results in:
 
-@subsubsection "irq": "" (since 3.0.0)
+@code{qemu-nbd -t -k /tmp/sock -f qcow2 file.qcow2 &}
+@code{nbdkit -f --filter=partition nbd socket=/tmp/sock partition=1}
 
-The ``irq'' property is obsoleted.
+Note that if you are exposing the export via /dev/nbd0, it is easier
+to just export the entire image and then mount only /dev/nbd0p1 than
+it is to reinvoke @command{qemu-nbd -c /dev/nbd0} limited to just a
+subset of the image.