[PULL 17/88] ppc/xive: Record the IPB in the associated NVT

[David Gibson]

From: Cédric Le Goater <address@hidden>

When an interrupt can not be presented to a vCPU, because it is not
running on any of the HW treads, the XIVE presenter updates the
Interrupt Pending Buffer register of the associated XIVE NVT
structure. This is only done if backlog is activated in the END but
this is generally the case.

The current code assumes that the fields of the NVT structure is
architected with the same layout of the thread interrupt context
registers. Fix this assumption and define an offset for the IPB
register backup value in the NVT.

Signed-off-by: Cédric Le Goater <address@hidden>
Message-Id: <address@hidden>
Reviewed-by: Greg Kurz <address@hidden>
Signed-off-by: David Gibson <address@hidden>
---
 hw/intc/xive.c             | 11 +++++++++--
 include/hw/ppc/xive_regs.h |  1 +
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/hw/intc/xive.c b/hw/intc/xive.c
index 3d472e29c8..177663d2b4 100644
--- a/hw/intc/xive.c
+++ b/hw/intc/xive.c
@@ -1607,14 +1607,21 @@ 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);
 
         /*
diff --git a/include/hw/ppc/xive_regs.h b/include/hw/ppc/xive_regs.h
index 55307cd153..530f232b04 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;
-- 
2.23.0