[PULL 14/50] ppc/xive: Explicitly zero NSR after accepting

Cédric Le Goater posted 50 patches 3 months, 3 weeks ago
Maintainers: Nicholas Piggin <npiggin@gmail.com>, "Frédéric Barrat" <fbarrat@linux.ibm.com>, Daniel Henrique Barboza <danielhb413@gmail.com>, Harsh Prateek Bora <harshpb@linux.ibm.com>
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[PULL 14/50] ppc/xive: Explicitly zero NSR after accepting
Posted by Cédric Le Goater 3 months, 3 weeks ago
From: Nicholas Piggin <npiggin@gmail.com>

Have xive_tctx_accept clear NSR in one shot rather than masking out bits
as they are tested, which makes it clear it's reset to 0, and does not
have a partial NSR value in the register.

Signed-off-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/20250512031100.439842-15-npiggin@gmail.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
---
 hw/intc/xive.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/hw/intc/xive.c b/hw/intc/xive.c
index a0a60a24f510..b35d2ec1793e 100644
--- a/hw/intc/xive.c
+++ b/hw/intc/xive.c
@@ -68,13 +68,11 @@ static uint64_t xive_tctx_accept(XiveTCTX *tctx, uint8_t ring)
          * If the interrupt was for a specific VP, reset the pending
          * buffer bit, otherwise clear the logical server indicator
          */
-        if (regs[TM_NSR] & TM_NSR_GRP_LVL) {
-            regs[TM_NSR] &= ~TM_NSR_GRP_LVL;
-        } else {
+        if (!(regs[TM_NSR] & TM_NSR_GRP_LVL)) {
             alt_regs[TM_IPB] &= ~xive_priority_to_ipb(cppr);
         }
 
-        /* Drop the exception bit and any group/crowd */
+        /* Clear the exception from NSR */
         regs[TM_NSR] = 0;
 
         trace_xive_tctx_accept(tctx->cs->cpu_index, alt_ring,
-- 
2.50.1