[PATCH] hw/acpi/cxl: Drop device-memory support from CFMWS entries

[Dan Williams]

While it was a reasonable idea to specify no window restricitions at the
outset of the CXL emulation support, it turns out that in practice a
platform will never follow the QEMU example of specifying simultaneous
support for HDM-H and HDM-D[B] in a single window.

HDM-D mandates extra bus cycles for host/device bias protocol, and HDM-DB
mandates extra bus cycles for back-invalidate protocol, so hardware must
be explicitly prepared for device-memory unlike host-only memory
(HDM-H).

In preparation for the kernel dropping support for windows that do not
select between device and host-only memory, move QEMU exclusively to
declaring host-only windows.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 hw/acpi/cxl.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/hw/acpi/cxl.c b/hw/acpi/cxl.c
index 2bf8c0799359..defb289e2fef 100644
--- a/hw/acpi/cxl.c
+++ b/hw/acpi/cxl.c
@@ -103,8 +103,8 @@ static void cedt_build_cfmws(GArray *table_data, CXLState 
*cxls)
         /* Host Bridge Interleave Granularity */
         build_append_int_noprefix(table_data, fw->enc_int_gran, 4);
 
-        /* Window Restrictions */
-        build_append_int_noprefix(table_data, 0x0f, 2); /* No restrictions */
+        /* Window Restrictions: Host-only ram and pmem */
+        build_append_int_noprefix(table_data, 0x0e, 2);
 
         /* QTG ID */
         build_append_int_noprefix(table_data, 0, 2);