[Qemu-devel] [PATCH v2 07/17] ppc/xive: Provide silent escalation support

["Cédric Le Goater" <clg@kaod.org>]

When the 's' bit is set the escalation is said to be 'silent' or
'silent/gather'. In such configuration, the notification sequence is
skipped and only the escalation sequence is performed. This is used to
configure all the EQs of a vCPU to escalate on a single EQ which will
then target the hypervisor.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
---
 include/hw/ppc/xive_regs.h | 2 ++
 hw/intc/xive.c             | 8 ++++++++
 2 files changed, 10 insertions(+)

diff --git a/include/hw/ppc/xive_regs.h b/include/hw/ppc/xive_regs.h
index 5d02ccfeff16..69af326ebf2c 100644
--- a/include/hw/ppc/xive_regs.h
+++ b/include/hw/ppc/xive_regs.h
@@ -209,6 +209,8 @@ typedef struct XiveEND {
 #define xive_end_is_escalate(end) (be32_to_cpu((end)->w0) & END_W0_ESCALATE_CTL)
 #define xive_end_is_uncond_escalation(end)              \
     (be32_to_cpu((end)->w0) & END_W0_UNCOND_ESCALATE)
+#define xive_end_is_silent_escalation(end)              \
+    (be32_to_cpu((end)->w0) & END_W0_SILENT_ESCALATE)
 
 static inline uint64_t xive_end_qaddr(XiveEND *end)
 {
diff --git a/hw/intc/xive.c b/hw/intc/xive.c
index c2e7e2d4c9a9..8ea97ac231a4 100644
--- a/hw/intc/xive.c
+++ b/hw/intc/xive.c
@@ -1463,6 +1463,13 @@ static void xive_router_end_notify(XiveRouter *xrtr, uint8_t end_blk,
         xive_router_write_end(xrtr, end_blk, end_idx, &end, 1);
     }
 
+    /*
+     * When the END is silent, we skip the notification part.
+     */
+    if (xive_end_is_silent_escalation(&end)) {
+        goto do_escalation;
+    }
+
     /*
      * The W7 format depends on the F bit in W6. It defines the type
      * of the notification :
@@ -1542,6 +1549,7 @@ static void xive_router_end_notify(XiveRouter *xrtr, uint8_t end_blk,
          */
     }
 
+do_escalation:
     /*
      * If activated, escalate notification using the ESe PQ bits and
      * the EAS in w4-5
-- 
2.21.0