[PATCH 3/9] ppc/xive: Record the IPB in the associated NVT

[Cédric Le Goater]

When an interrupt can not be presented to a vCPU, the XIVE presenter
updates the Interrupt Pending Buffer of the XIVE NVT if backlog is
activated in the END.

Signed-off-by: Cédric Le Goater <c...@kaod.org>
---
 include/hw/ppc/xive_regs.h |  1 +
 hw/intc/xive.c             | 11 +++++++++--
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/include/hw/ppc/xive_regs.h b/include/hw/ppc/xive_regs.h
index 55307cd1533c..530f232b04f8 100644
--- a/include/hw/ppc/xive_regs.h
+++ b/include/hw/ppc/xive_regs.h
@@ -255,6 +255,7 @@ typedef struct XiveNVT {
         uint32_t        w2;
         uint32_t        w3;
         uint32_t        w4;
+#define NVT_W4_IPB               PPC_BITMASK32(16, 23)
         uint32_t        w5;
         uint32_t        w6;
         uint32_t        w7;
diff --git a/hw/intc/xive.c b/hw/intc/xive.c
index cbe4ae6c294d..2bf7b4ad7006 100644
--- a/hw/intc/xive.c
+++ b/hw/intc/xive.c
@@ -1600,14 +1600,21 @@ static void xive_router_end_notify(XiveRouter *xrtr, 
uint8_t end_blk,
      * - logical server : forward request to IVPE (not supported)
      */
     if (xive_end_is_backlog(&end)) {
+        uint8_t ipb;
+
         if (format == 1) {
             qemu_log_mask(LOG_GUEST_ERROR,
                           "XIVE: END %x/%x invalid config: F1 & backlog\n",
                           end_blk, end_idx);
             return;
         }
-        /* Record the IPB in the associated NVT structure */
-        ipb_update((uint8_t *) &nvt.w4, priority);
+        /*
+         * Record the IPB in the associated NVT structure for later
+         * use. The presenter will resend the interrupt when the vCPU
+         * is dispatched again on a HW thread.
+         */
+        ipb = xive_get_field32(NVT_W4_IPB, nvt.w4) | priority_to_ipb(priority);
+        nvt.w4 = xive_set_field32(NVT_W4_IPB, nvt.w4, ipb);
         xive_router_write_nvt(xrtr, nvt_blk, nvt_idx, &nvt, 4);
 
         /*
-- 
2.21.0