[Qemu-devel] [PATCH qemu] target/ppc: Add Directed Privileged Door-bell Exception State (DPDES) SPR

[Alexey Kardashevskiy <aik@ozlabs.ru>]

DPDES stores a status of a doorbell message and if it is lost in
migration, the destination CPU won't receive it. This does not hit us
much as IPIs complete too quick to catch a pending one and even if
we missed one, broadcasts happen often enough to wake that CPU.

This defines DPDES and registers with KVM for migration.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 target/ppc/cpu.h                |  1 +
 target/ppc/translate_init.inc.c | 14 ++++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
index 64799386f9ab..f0521a435d2d 100644
--- a/target/ppc/cpu.h
+++ b/target/ppc/cpu.h
@@ -1466,6 +1466,7 @@ typedef PowerPCCPU ArchCPU;
 #define SPR_MPC_ICTRL         (0x09E)
 #define SPR_MPC_BAR           (0x09F)
 #define SPR_PSPB              (0x09F)
+#define SPR_DPDES             (0x0B0)
 #define SPR_DAWR              (0x0B4)
 #define SPR_RPR               (0x0BA)
 #define SPR_CIABR             (0x0BB)
diff --git a/target/ppc/translate_init.inc.c b/target/ppc/translate_init.inc.c
index c9fcd87095f5..7e41ae145600 100644
--- a/target/ppc/translate_init.inc.c
+++ b/target/ppc/translate_init.inc.c
@@ -8198,6 +8198,18 @@ static void gen_spr_power8_pspb(CPUPPCState *env)
                      KVM_REG_PPC_PSPB, 0);
 }
 
+static void gen_spr_power8_dpdes(CPUPPCState *env)
+{
+#if !defined(CONFIG_USER_ONLY)
+    /* Directed Privileged Door-bell Exception State, used for IPI */
+    spr_register_kvm_hv(env, SPR_DPDES, "DPDES",
+                        SPR_NOACCESS, SPR_NOACCESS,
+                        &spr_read_generic, SPR_NOACCESS,
+                        &spr_read_generic, &spr_write_generic,
+                        KVM_REG_PPC_DPDES, 0x00000000);
+#endif
+}
+
 static void gen_spr_power8_ic(CPUPPCState *env)
 {
 #if !defined(CONFIG_USER_ONLY)
@@ -8629,6 +8641,7 @@ static void init_proc_POWER8(CPUPPCState *env)
     gen_spr_power8_pmu_user(env);
     gen_spr_power8_tm(env);
     gen_spr_power8_pspb(env);
+    gen_spr_power8_dpdes(env);
     gen_spr_vtb(env);
     gen_spr_power8_ic(env);
     gen_spr_power8_book4(env);
@@ -8817,6 +8830,7 @@ static void init_proc_POWER9(CPUPPCState *env)
     gen_spr_power8_pmu_user(env);
     gen_spr_power8_tm(env);
     gen_spr_power8_pspb(env);
+    gen_spr_power8_dpdes(env);
     gen_spr_vtb(env);
     gen_spr_power8_ic(env);
     gen_spr_power8_book4(env);
-- 
2.17.1