[PATCH v4 12/14] pnv/xive: Update PIPR when updating CPPR

[Michael Kowal]

From: Glenn Miles <milesg@linux.ibm.com>

Current code was updating the PIPR inside the xive_tctx_accept() function
instead of the xive_tctx_set_cppr function, which is where the HW would
have it updated.

Moved the update to the xive_tctx_set_cppr function which required
additional support for pool interrupts.

Fixes: cdd4de68edb6 ("ppc/xive: notify the CPU when the interrupt priority is 
more privileged")
Signed-off-by: Glenn Miles <milesg@linux.vnet.ibm.com>
Signed-off-by: Michael Kowal <kowal@linux.ibm.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
---
 hw/intc/xive.c | 34 ++++++++++++++++++++++++++++++++--
 1 file changed, 32 insertions(+), 2 deletions(-)

diff --git a/hw/intc/xive.c b/hw/intc/xive.c
index 5c5c3a2dd6..738eaf624d 100644
--- a/hw/intc/xive.c
+++ b/hw/intc/xive.c
@@ -89,7 +89,6 @@ static uint64_t xive_tctx_accept(XiveTCTX *tctx, uint8_t ring)
 
         /* Reset the pending buffer bit */
         alt_regs[TM_IPB] &= ~xive_priority_to_ipb(cppr);
-        regs[TM_PIPR] = ipb_to_pipr(alt_regs[TM_IPB]);
 
         /* Drop Exception bit */
         regs[TM_NSR] &= ~mask;
@@ -143,6 +142,8 @@ void xive_tctx_reset_signal(XiveTCTX *tctx, uint8_t ring)
 static void xive_tctx_set_cppr(XiveTCTX *tctx, uint8_t ring, uint8_t cppr)
 {
     uint8_t *regs = &tctx->regs[ring];
+    uint8_t pipr_min;
+    uint8_t ring_min;
 
     trace_xive_tctx_set_cppr(tctx->cs->cpu_index, ring,
                              regs[TM_IPB], regs[TM_PIPR],
@@ -154,8 +155,37 @@ static void xive_tctx_set_cppr(XiveTCTX *tctx, uint8_t 
ring, uint8_t cppr)
 
     tctx->regs[ring + TM_CPPR] = cppr;
 
+    /*
+     * Recompute the PIPR based on local pending interrupts.  The PHYS
+     * ring must take the minimum of both the PHYS and POOL PIPR values.
+     */
+    pipr_min = ipb_to_pipr(regs[TM_IPB]);
+    ring_min = ring;
+
+    /* PHYS updates also depend on POOL values */
+    if (ring == TM_QW3_HV_PHYS) {
+        uint8_t *pool_regs = &tctx->regs[TM_QW2_HV_POOL];
+
+        /* POOL values only matter if POOL ctx is valid */
+        if (pool_regs[TM_WORD2] & 0x80) {
+
+            uint8_t pool_pipr = ipb_to_pipr(pool_regs[TM_IPB]);
+
+            /*
+             * Determine highest priority interrupt and
+             * remember which ring has it.
+             */
+            if (pool_pipr < pipr_min) {
+                pipr_min = pool_pipr;
+                ring_min = TM_QW2_HV_POOL;
+            }
+        }
+    }
+
+    regs[TM_PIPR] = pipr_min;
+
     /* CPPR has changed, check if we need to raise a pending exception */
-    xive_tctx_notify(tctx, ring);
+    xive_tctx_notify(tctx, ring_min);
 }
 
 void xive_tctx_ipb_update(XiveTCTX *tctx, uint8_t ring, uint8_t ipb)
-- 
2.43.0