[PATCH v2 1/6] docs/about/removed-features: Document removed CLI options from QEMU v2.12

[Thomas Huth <thuth@redhat.com>]

These CLI options had been removed/replaced in QEMU v2.12. Still, some
people might want to update from older versions to the recent QEMU version,
so we should give some recommendations for the replacements in our
documentation.

Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 docs/about/removed-features.rst | 39 +++++++++++++++++++++++++++++++--
 1 file changed, 37 insertions(+), 2 deletions(-)

diff --git a/docs/about/removed-features.rst b/docs/about/removed-features.rst
index 07d597847c..c18af3c76f 100644
--- a/docs/about/removed-features.rst
+++ b/docs/about/removed-features.rst
@@ -9,8 +9,43 @@ trouble after a recent upgrade.
 System emulator command line arguments
 --------------------------------------
 
-``-net ...,name=``\ *name* (removed in 5.1)
-'''''''''''''''''''''''''''''''''''''''''''
+``-hdachs`` (removed in 2.12)
+'''''''''''''''''''''''''''''
+
+The geometry defined by ``-hdachs c,h,s,t`` should now be specified via
+``-device ide-hd,drive=dr,cyls=c,heads=h,secs=s,bios-chs-trans=t``
+(together with ``-drive if=none,id=dr,...``).
+
+``-net channel`` (removed in 2.12)
+''''''''''''''''''''''''''''''''''
+
+This option has been replaced by ``-net user,guestfwd=...``.
+
+``-net dump`` (removed in 2.12)
+'''''''''''''''''''''''''''''''
+
+``-net dump[,vlan=n][,file=filename][,len=maxlen]`` has been replaced by
+``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=maxlen]``.
+Note that the new syntax works with netdev IDs instead of the old "vlan" hubs.
+
+``-no-kvm-pit`` (removed in 2.12)
+'''''''''''''''''''''''''''''''''
+
+This was just a dummy option that has been ignored, since the in-kernel PIT
+cannot be disabled separately from the irqchip anymore. A similar effect
+(which also disables the KVM IOAPIC) can be obtained with
+``-M kernel_irqchip=split``.
+
+``-tdf`` (removed in 2.12)
+''''''''''''''''''''''''''
+
+There is no replacement, the ``-tdf`` option has just been ignored since the
+behaviour that could be changed by this option in qemu-kvm is now the default
+when using the KVM PIT. It still can be requested explicitly using
+``-global kvm-pit.lost_tick_policy=delay``.
+
+``-net ...,name=...`` (removed in 5.1)
+''''''''''''''''''''''''''''''''''''''
 
 The ``name`` parameter of the ``-net`` option was a synonym
 for the ``id`` parameter, which should now be used instead.
-- 
2.27.0