ppc/xive2: Support group-matching when looking for target

If an END has the 'i' bit set (ignore), then it targets a group of
VPs. The size of the group depends on the VP index of the target
(first 0 found when looking at the least significant bits of the
index) so a mask is applied on the VP index of a running thread to
know if we have a match.

Signed-off-by: Frederic Barrat <fbarrat@linux.ibm.com>
Signed-off-by: Michael Kowal <kowal@linux.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>

1 files changed, 25 insertions, 13 deletions

diff --git a/hw/intc/pnv_xive2.c b/hw/intc/pnv_xive2.c
index 9ed759417e..8429ccbd51 100644
--- a/hw/intc/pnv_xive2.c
+++ b/hw/intc/pnv_xive2.c
@@ -1,10 +1,9 @@
 /*
  * QEMU PowerPC XIVE2 interrupt controller model  (POWER10)
  *
- * Copyright (c) 2019-2022, IBM Corporation.
+ * Copyright (c) 2019-2024, IBM Corporation.
  *
- * This code is licensed under the GPL version 2 or later. See the
- * COPYING file in the top-level directory.
+ * SPDX-License-Identifier: GPL-2.0-or-later
  */
 
 #include "qemu/osdep.h"
@@ -660,21 +659,34 @@ static int pnv_xive2_match_nvt(XivePresenter *xptr, uint8_t format,
                                                    logic_serv);
             }
 
-            /*
-             * Save the context and follow on to catch duplicates,
-             * that we don't support yet.
-             */
             if (ring != -1) {
-                if (match->tctx) {
+                /*
+                 * For VP-specific match, finding more than one is a
+                 * problem. For group notification, it's possible.
+                 */
+                if (!cam_ignore && match->tctx) {
                     qemu_log_mask(LOG_GUEST_ERROR, "XIVE: already found a "
                                   "thread context NVT %x/%x\n",
                                   nvt_blk, nvt_idx);
-                    return false;
+                    /* Should set a FIR if we ever model it */
+                    return -1;
+                }
+                /*
+                 * For a group notification, we need to know if the
+                 * match is precluded first by checking the current
+                 * thread priority. If the interrupt can be delivered,
+                 * we always notify the first match (for now).
+                 */
+                if (cam_ignore &&
+                    xive2_tm_irq_precluded(tctx, ring, priority)) {
+                        match->precluded = true;
+                } else {
+                    if (!match->tctx) {
+                        match->ring = ring;
+                        match->tctx = tctx;
+                    }
+                    count++;
                 }
-
-                match->ring = ring;
-                match->tctx = tctx;
-                count++;
             }
         }
     }