ppc/xive: Explicitly zero NSR after accepting

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>

diff --git a/hw/intc/xive.c b/hw/intc/xive.c
index a0a60a24f510ade246dc8841328058a73d0a2071..b35d2ec1793e704de19bdcea32ef975e2e57aee8 100644 (file)
--- 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,