ppc/xive2: redistribute group interrupts on context push

When pushing a context, any presented group interrupt should be
redistributed before processing pending interrupts to present
highest priority.

This can occur when pushing the POOL ring when the valid PHYS
ring has a group interrupt presented, because they share signal
registers.

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/20250512031100.439842-46-npiggin@gmail.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>

diff --git a/hw/intc/xive2.c b/hw/intc/xive2.c
index 4244e1d02b618e1c13d2254270042951d8593345..23eb85bb86690a00824e81714f05cbd86becd26d 100644 (file)
--- a/hw/intc/xive2.c
+++ b/hw/intc/xive2.c
@@ -945,8 +945,9 @@ static void xive2_tctx_need_resend(Xive2Router *xrtr, XiveTCTX *tctx,
                                    uint8_t nvp_blk, uint32_t nvp_idx,
                                    bool do_restore)
 {
+    uint8_t *sig_regs = xive_tctx_signal_regs(tctx, ring);
     uint8_t *regs = &tctx->regs[ring];
-    uint8_t ipb;
+    uint8_t ipb, nsr = sig_regs[TM_NSR];
     Xive2Nvp nvp;
 
     /*
@@ -978,6 +979,11 @@ static void xive2_tctx_need_resend(Xive2Router *xrtr, XiveTCTX *tctx,
     /* IPB bits in the backlog are merged with the TIMA IPB bits */
     regs[TM_IPB] |= ipb;
 
+    if (xive_nsr_indicates_group_exception(ring, nsr)) {
+        /* redistribute precluded active grp interrupt */
+        g_assert(ring == TM_QW2_HV_POOL); /* PHYS ring has the grp interrupt */
+        xive2_redistribute(xrtr, tctx, xive_nsr_exception_ring(ring, nsr));
+    }
     xive2_tctx_process_pending(tctx, ring == TM_QW2_HV_POOL ?
                                          TM_QW3_HV_PHYS : ring);
 }