[PATCH 3/5] hw/cxl: Allow BI by default in Window restrictions

[Davidlohr Bueso <dave@stgolabs.net>]

Update the CFMW restrictions to also permit Back-Invalidate
flows by default, which is aligned with the no-restrictions
policy.

While at it, document the 'restrictions=' option.

Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
---
 hw/cxl/cxl-host.c | 2 +-
 qapi/machine.json | 3 ++-
 qemu-options.hx   | 4 +++-
 3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/hw/cxl/cxl-host.c b/hw/cxl/cxl-host.c
index def2cf75be61..0d17ea3e4c26 100644
--- a/hw/cxl/cxl-host.c
+++ b/hw/cxl/cxl-host.c
@@ -64,7 +64,7 @@ static void cxl_fixed_memory_window_config(CXLFixedMemoryWindowOptions *object,
     if (object->has_restrictions) {
         fw->restrictions = object->restrictions;
     } else {
-        fw->restrictions = 0xf; /* No restrictions */
+        fw->restrictions = 0x2f; /* No restrictions */
     }
 
     fw->targets = g_malloc0_n(fw->num_targets, sizeof(*fw->targets));
diff --git a/qapi/machine.json b/qapi/machine.json
index ac258578e4ab..ea8ba71305b0 100644
--- a/qapi/machine.json
+++ b/qapi/machine.json
@@ -589,7 +589,8 @@
 #     BIT(2) - Volatile
 #     BIT(3) - Persistent
 #     BIT(4) - Fixed Device Config
-#     Default is 0xF
+#     BIT(5) - BI
+#     Default is 0x2F
 #
 # @targets: Target root bridge IDs from -device ...,id=<ID> for each
 #     root bridge.
diff --git a/qemu-options.hx b/qemu-options.hx
index 1f862b19a676..2da65fad3c9f 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -142,7 +142,7 @@ SRST
             -machine memory-backend=pc.ram
             -m 512M
 
-    ``cxl-fmw.0.targets.0=firsttarget,cxl-fmw.0.targets.1=secondtarget,cxl-fmw.0.size=size[,cxl-fmw.0.interleave-granularity=granularity]``
+    ``cxl-fmw.0.targets.0=firsttarget,cxl-fmw.0.targets.1=secondtarget,cxl-fmw.0.size=size[,cxl-fmw.0.interleave-granularity=granularity,restrictions=restrictions]``
         Define a CXL Fixed Memory Window (CFMW).
 
         Described in the CXL 2.0 ECN: CEDT CFMWS & QTG _DSM.
@@ -168,6 +168,8 @@ SRST
         interleave. Default 256 (bytes). Only 256, 512, 1k, 2k,
         4k, 8k and 16k granularities supported.
 
+        ``restrictions=restrictions`` bitmask with the restrictions of the CFMW.
+
         Example:
 
         ::
-- 
2.39.5