ppc/xive: Add xive_tctx_pipr_set() helper function

Have xive_tctx_notify() also set the new PIPR value and rename it to
xive_tctx_pipr_set(). This can replace the last xive_tctx_pipr_update()
caller because it does not need to update IPB (it already sets it).

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Glenn Miles <milesg@linux.ibm.com>
Reviewed-by: Michael Kowal <kowal@linux.ibm.com>
Tested-by: Gautam Menghani <gautam@linux.ibm.com>
Link: https://lore.kernel.org/qemu-devel/20250512031100.439842-36-npiggin@gmail.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>

3 files changed, 20 insertions, 40 deletions

diff --git a/hw/intc/xive.c b/hw/intc/xive.c
index db26dae..6ad84f9 100644
--- a/hw/intc/xive.c
+++ b/hw/intc/xive.c
@@ -125,12 +125,16 @@ uint64_t xive_tctx_accept(XiveTCTX *tctx, uint8_t sig_ring)
     return ((uint64_t)nsr << 8) | sig_regs[TM_CPPR];
 }
 
-void xive_tctx_notify(XiveTCTX *tctx, uint8_t ring, uint8_t group_level)
+/* Change PIPR and calculate NSR and irq based on PIPR, CPPR, group */
+void xive_tctx_pipr_set(XiveTCTX *tctx, uint8_t ring, uint8_t pipr,
+                        uint8_t group_level)
 {
     uint8_t *sig_regs = xive_tctx_signal_regs(tctx, ring);
     uint8_t *regs = &tctx->regs[ring];
 
-    if (sig_regs[TM_PIPR] < sig_regs[TM_CPPR]) {
+    sig_regs[TM_PIPR] = pipr;
+
+    if (pipr < sig_regs[TM_CPPR]) {
         switch (ring) {
         case TM_QW1_OS:
             sig_regs[TM_NSR] = TM_QW1_NSR_EO | (group_level & 0x3F);
@@ -145,7 +149,7 @@ void xive_tctx_notify(XiveTCTX *tctx, uint8_t ring, uint8_t group_level)
             g_assert_not_reached();
         }
         trace_xive_tctx_notify(tctx->cs->cpu_index, ring,
-                               regs[TM_IPB], sig_regs[TM_PIPR],
+                               regs[TM_IPB], pipr,
                                sig_regs[TM_CPPR], sig_regs[TM_NSR]);
         qemu_irq_raise(xive_tctx_output(tctx, ring));
     } else {
@@ -213,29 +217,10 @@ static void xive_tctx_set_cppr(XiveTCTX *tctx, uint8_t ring, uint8_t cppr)
         }
     }
 
-    sig_regs[TM_PIPR] = pipr_min;
-
-    /* CPPR has changed, check if we need to raise a pending exception */
-    xive_tctx_notify(tctx, ring_min, 0);
+    /* CPPR has changed, this may present or preclude a pending exception */
+    xive_tctx_pipr_set(tctx, ring_min, pipr_min, 0);
 }
 
-void xive_tctx_pipr_update(XiveTCTX *tctx, uint8_t ring, uint8_t priority,
-                           uint8_t group_level)
-{
-    uint8_t *sig_regs = xive_tctx_signal_regs(tctx, ring);
-    uint8_t *regs = &tctx->regs[ring];
-
-    if (group_level == 0) {
-        /* VP-specific */
-        regs[TM_IPB] |= xive_priority_to_ipb(priority);
-        sig_regs[TM_PIPR] = xive_ipb_to_pipr(regs[TM_IPB]);
-    } else {
-        /* VP-group */
-        sig_regs[TM_PIPR] = xive_priority_to_pipr(priority);
-    }
-    xive_tctx_notify(tctx, ring, group_level);
- }
-
 static void xive_tctx_pipr_recompute_from_ipb(XiveTCTX *tctx, uint8_t ring)
 {
     uint8_t *sig_regs = xive_tctx_signal_regs(tctx, ring);
@@ -244,8 +229,7 @@ static void xive_tctx_pipr_recompute_from_ipb(XiveTCTX *tctx, uint8_t ring)
     /* Does not support a presented group interrupt */
     g_assert(!xive_nsr_indicates_group_exception(ring, sig_regs[TM_NSR]));
 
-    sig_regs[TM_PIPR] = xive_ipb_to_pipr(regs[TM_IPB]);
-    xive_tctx_notify(tctx, ring, 0);
+    xive_tctx_pipr_set(tctx, ring, xive_ipb_to_pipr(regs[TM_IPB]), 0);
 }
 
 void xive_tctx_pipr_present(XiveTCTX *tctx, uint8_t ring, uint8_t priority,
@@ -264,8 +248,7 @@ void xive_tctx_pipr_present(XiveTCTX *tctx, uint8_t ring, uint8_t priority,
     }
     g_assert(pipr <= xive_ipb_to_pipr(regs[TM_IPB]));
     g_assert(pipr < sig_regs[TM_PIPR]);
-    sig_regs[TM_PIPR] = pipr;
-    xive_tctx_notify(tctx, ring, group_level);
+    xive_tctx_pipr_set(tctx, ring, pipr, group_level);
 }
 
 /*
diff --git a/hw/intc/xive2.c b/hw/intc/xive2.c
index 71b40f7..0ee50a6 100644
--- a/hw/intc/xive2.c
+++ b/hw/intc/xive2.c
@@ -966,10 +966,10 @@ static void xive2_tctx_need_resend(Xive2Router *xrtr, XiveTCTX *tctx,
     }
 
     /*
-     * Compute the PIPR based on the restored state.
+     * Set the PIPR/NSR based on the restored state.
      * It will raise the External interrupt signal if needed.
      */
-    xive_tctx_pipr_update(tctx, TM_QW1_OS, backlog_prio, backlog_level);
+    xive_tctx_pipr_set(tctx, TM_QW1_OS, backlog_prio, backlog_level);
 }
 
 /*
@@ -1144,8 +1144,7 @@ static void xive2_tctx_set_cppr(XiveTCTX *tctx, uint8_t ring, uint8_t cppr)
             }
 
             /* interrupt is VP directed, pending in IPB */
-            sig_regs[TM_PIPR] = cppr;
-            xive_tctx_notify(tctx, ring, 0); /* Ensure interrupt is cleared */
+            xive_tctx_pipr_set(tctx, ring, cppr, 0);
             return;
         } else {
             /* CPPR was lowered, but still above PIPR. No action needed. */
@@ -1255,11 +1254,10 @@ again:
         pipr_min = backlog_prio;
     }
 
-    /* PIPR should not be set to a value greater than CPPR */
-    sig_regs[TM_PIPR] = (pipr_min > cppr) ? cppr : pipr_min;
-
-    /* CPPR has changed, check if we need to raise a pending exception */
-    xive_tctx_notify(tctx, ring_min, group_level);
+    if (pipr_min > cppr) {
+        pipr_min = cppr;
+    }
+    xive_tctx_pipr_set(tctx, ring_min, pipr_min, group_level);
 }
 
 void xive2_tm_set_hv_cppr(XivePresenter *xptr, XiveTCTX *tctx,
diff --git a/include/hw/ppc/xive.h b/include/hw/ppc/xive.h
index a3c2f50..2372d10 100644
--- a/include/hw/ppc/xive.h
+++ b/include/hw/ppc/xive.h
@@ -584,12 +584,11 @@ void xive_tctx_pic_print_info(XiveTCTX *tctx, GString *buf);
 Object *xive_tctx_create(Object *cpu, XivePresenter *xptr, Error **errp);
 void xive_tctx_reset(XiveTCTX *tctx);
 void xive_tctx_destroy(XiveTCTX *tctx);
-void xive_tctx_pipr_update(XiveTCTX *tctx, uint8_t ring, uint8_t priority,
-                           uint8_t group_level);
+void xive_tctx_pipr_set(XiveTCTX *tctx, uint8_t ring, uint8_t priority,
+                        uint8_t group_level);
 void xive_tctx_pipr_present(XiveTCTX *tctx, uint8_t ring, uint8_t priority,
                             uint8_t group_level);
 void xive_tctx_reset_signal(XiveTCTX *tctx, uint8_t ring);
-void xive_tctx_notify(XiveTCTX *tctx, uint8_t ring, uint8_t group_level);
 uint64_t xive_tctx_accept(XiveTCTX *tctx, uint8_t ring);
 
 /*