hw/arm/virt: Support TCG GICv4

Add support for the TCG GICv4 to the virt board. For the board,
the GICv4 is very similar to the GICv3, with the only difference
being the size of the redistributor frame. The changes here are thus:
 * calculating virt_redist_capacity correctly for GICv4
 * changing various places which were "if GICv3" to be "if not GICv2"
 * the commandline option handling

Note that using GICv4 reduces the maximum possible number of CPUs on
the virt board from 512 to 317, because we can now only fit half as
many redistributors into the redistributor regions we have defined.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220408141550.1271295-42-peter.maydell@linaro.org

1 files changed, 4 insertions, 1 deletions

diff --git a/docs/system/arm/virt.rst b/docs/system/arm/virt.rst
index 1297dff..5fe045c 100644
--- a/docs/system/arm/virt.rst
+++ b/docs/system/arm/virt.rst
@@ -99,11 +99,14 @@ gic-version
     GICv2. Note that this limits the number of CPUs to 8.
   ``3``
     GICv3. This allows up to 512 CPUs.
+  ``4``
+    GICv4. Requires ``virtualization`` to be ``on``; allows up to 317 CPUs.
   ``host``
     Use the same GIC version the host provides, when using KVM
   ``max``
     Use the best GIC version possible (same as host when using KVM;
-    currently same as ``3``` for TCG, but this may change in future)
+    with TCG this is currently ``3`` if ``virtualization`` is ``off`` and
+    ``4`` if ``virtualization`` is ``on``, but this may change in future)
 
 its
   Set ``on``/``off`` to enable/disable ITS instantiation. The default is ``on``