[PATCH v3 2/2] 2.3.2 MMIO: Add config space version register

[Pawel Moll <pawel.moll@arm.com>]

... to allow synchronisation between the guest and the host.

Based on Rusty's original patch, see VIRTIO-35.

Signed-off-by: Pawel Moll <pawel.moll@arm.com>
---
 virtio-v1.0-wd01-part1-specification.txt | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/virtio-v1.0-wd01-part1-specification.txt b/virtio-v1.0-wd01-part1-specification.txt
index 559ef75..e812f8d 100644
--- a/virtio-v1.0-wd01-part1-specification.txt
+++ b/virtio-v1.0-wd01-part1-specification.txt
@@ -1431,6 +1431,13 @@ configuration space. The following list presents their layout:
   only when QueueReady is set to zero (0x0), so when the queue
   is not in use.
 
+* 0x0fc | R | ConfigGeneration
+  Configuration atomicity value.
+  Changes every time the configuration noticeably changes. This
+  means the device may only change the value after a configuration
+  read operation, but it must change if there is any risk of a
+  device seeing an inconsistent configuration state.
+
 * 0x100+ | RW | Config
   Device-specific configuration space starts at an offset 0x100
   and is accessed with byte alignment. Its meaning and size
-- 
1.8.1.2