From: Michael Kowal <kowal@linux.ibm.com>

Writes to the Flush Control registers were logged as invalid
when they are allowed. Clearing the unsupported want_cache_disable
feature is supported, so don't log an error in that case.

Signed-off-by: Michael Kowal <kowal@linux.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Glenn Miles <milesg@linux.ibm.com>
Reviewed-by: Michael Kowal <kowal@linux.ibm.com>
Reviewed-by: Caleb Schlossin <calebs@linux.ibm.com>
Tested-by: Gautam Menghani <gautam@linux.ibm.com>
Link: https://lore.kernel.org/qemu-devel/20250512031100.439842-21-npiggin@gmail.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
---
 hw/intc/pnv_xive2.c | 36 ++++++++++++++++++++++++++++++++----
 1 file changed, 32 insertions(+), 4 deletions(-)

diff --git a/hw/intc/pnv_xive2.c b/hw/intc/pnv_xive2.c
index e15f414d0bb3..386175a68b29 100644
--- a/hw/intc/pnv_xive2.c
+++ b/hw/intc/pnv_xive2.c
@@ -1411,7 +1411,14 @@ static void pnv_xive2_ic_vc_write(void *opaque, hwaddr offset,
     /*
      * ESB cache updates (not modeled)
      */
-    /* case VC_ESBC_FLUSH_CTRL: */
+    case VC_ESBC_FLUSH_CTRL:
+        if (val & VC_ESBC_FLUSH_CTRL_WANT_CACHE_DISABLE) {
+            xive2_error(xive, "VC: unsupported write @0x%"HWADDR_PRIx
+                        " value 0x%"PRIx64" bit[2] poll_want_cache_disable",
+                        offset, val);
+            return;
+        }
+        break;
     case VC_ESBC_FLUSH_POLL:
         xive->vc_regs[VC_ESBC_FLUSH_CTRL >> 3] |= VC_ESBC_FLUSH_CTRL_POLL_VALID;
         /* ESB update */
@@ -1427,7 +1434,14 @@ static void pnv_xive2_ic_vc_write(void *opaque, hwaddr offset,
     /*
      * EAS cache updates (not modeled)
      */
-    /* case VC_EASC_FLUSH_CTRL: */
+    case VC_EASC_FLUSH_CTRL:
+        if (val & VC_EASC_FLUSH_CTRL_WANT_CACHE_DISABLE) {
+            xive2_error(xive, "VC: unsupported write @0x%"HWADDR_PRIx
+                        " value 0x%"PRIx64" bit[2] poll_want_cache_disable",
+                        offset, val);
+            return;
+        }
+        break;
     case VC_EASC_FLUSH_POLL:
         xive->vc_regs[VC_EASC_FLUSH_CTRL >> 3] |= VC_EASC_FLUSH_CTRL_POLL_VALID;
         /* EAS update */
@@ -1466,7 +1480,14 @@ static void pnv_xive2_ic_vc_write(void *opaque, hwaddr offset,
         break;
 
 
-    /* case VC_ENDC_FLUSH_CTRL: */
+    case VC_ENDC_FLUSH_CTRL:
+        if (val & VC_ENDC_FLUSH_CTRL_WANT_CACHE_DISABLE) {
+            xive2_error(xive, "VC: unsupported write @0x%"HWADDR_PRIx
+                        " value 0x%"PRIx64" bit[2] poll_want_cache_disable",
+                        offset, val);
+            return;
+        }
+        break;
     case VC_ENDC_FLUSH_POLL:
         xive->vc_regs[VC_ENDC_FLUSH_CTRL >> 3] |= VC_ENDC_FLUSH_CTRL_POLL_VALID;
         break;
@@ -1687,7 +1708,14 @@ static void pnv_xive2_ic_pc_write(void *opaque, hwaddr offset,
         pnv_xive2_nxc_update(xive, watch_engine);
         break;
 
-   /* case PC_NXC_FLUSH_CTRL: */
+    case PC_NXC_FLUSH_CTRL:
+        if (val & PC_NXC_FLUSH_CTRL_WANT_CACHE_DISABLE) {
+            xive2_error(xive, "VC: unsupported write @0x%"HWADDR_PRIx
+                        " value 0x%"PRIx64" bit[2] poll_want_cache_disable",
+                        offset, val);
+            return;
+        }
+        break;
     case PC_NXC_FLUSH_POLL:
         xive->pc_regs[PC_NXC_FLUSH_CTRL >> 3] |= PC_NXC_FLUSH_CTRL_POLL_VALID;
         break;
-- 
2.50.1