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From: Nicholas Piggin <npiggin@gmail.com>
To: qemu-devel@nongnu.org
Cc: Nicholas Piggin <npiggin@gmail.com>,
	qemu-ppc@nongnu.org, qemu-stable@nongnu.org
Subject: [PULL 1/2] target/ppc: Big-core scratch register fix
Date: Tue,  8 Apr 2025 22:45:48 +1000	[thread overview]
Message-ID: <20250408124550.40485-2-npiggin@gmail.com> (raw)
In-Reply-To: <20250408124550.40485-1-npiggin@gmail.com>

The per-core SCRATCH0-7 registers are shared between big cores, which
was missed in the big-core implementation. It is difficult to model
well with the big-core == 2xPnvCore scheme we moved to, this fix
uses the even PnvCore to store the scrach data.

Also remove a stray log message that came in with the same patch that
introduced patch.

Fixes: c26504afd5f5c ("ppc/pnv: Add a big-core mode that joins two regular cores")
Cc: qemu-stable@nongnu.org
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 target/ppc/misc_helper.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/target/ppc/misc_helper.c b/target/ppc/misc_helper.c
index 2d9512c116..46ae454afd 100644
--- a/target/ppc/misc_helper.c
+++ b/target/ppc/misc_helper.c
@@ -332,6 +332,10 @@ target_ulong helper_load_sprd(CPUPPCState *env)
     PnvCore *pc = pnv_cpu_state(cpu)->pnv_core;
     target_ulong sprc = env->spr[SPR_POWER_SPRC];
 
+    if (pc->big_core) {
+        pc = pnv_chip_find_core(pc->chip, CPU_CORE(pc)->core_id & ~0x1);
+    }
+
     switch (sprc & 0x3e0) {
     case 0: /* SCRATCH0-3 */
     case 1: /* SCRATCH4-7 */
@@ -368,6 +372,10 @@ void helper_store_sprd(CPUPPCState *env, target_ulong val)
     PnvCore *pc = pnv_cpu_state(cpu)->pnv_core;
     int nr;
 
+    if (pc->big_core) {
+        pc = pnv_chip_find_core(pc->chip, CPU_CORE(pc)->core_id & ~0x1);
+    }
+
     switch (sprc & 0x3e0) {
     case 0: /* SCRATCH0-3 */
     case 1: /* SCRATCH4-7 */
@@ -378,7 +386,6 @@ void helper_store_sprd(CPUPPCState *env, target_ulong val)
          * information. Could also dump these upon checkstop.
          */
         nr = (sprc >> 3) & 0x7;
-        qemu_log("SPRD write 0x" TARGET_FMT_lx " to SCRATCH%d\n", val, nr);
         pc->scratch[nr] = val;
         break;
     default:
-- 
2.47.1



  reply	other threads:[~2025-04-08 12:46 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-04-08 12:45 [PULL 0/2] ppc-for-10.0-3 queue Nicholas Piggin
2025-04-08 12:45 ` Nicholas Piggin [this message]
2025-04-24  8:25   ` [PULL 1/2] target/ppc: Big-core scratch register fix Thomas Huth
2025-04-30  0:00     ` Nicholas Piggin
2025-04-30  5:56       ` Thomas Huth
2025-04-08 12:45 ` [PULL 2/2] target/ppc: Fix SPRC/SPRD SPRs for P9/10 Nicholas Piggin
2025-04-09  8:31 ` [PULL 0/2] ppc-for-10.0-3 queue Stefan Hajnoczi

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