[PATCH 5/6] target/ppc: Add SRR1 prefix indication to interrupt handlers

[Nicholas Piggin <npiggin@gmail.com>]

ISA v3.1 introduced prefix instructions. Among the changes, various
synchronous interrupts report whether they were caused by a prefix
instruction in (H)SRR1.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 target/ppc/excp_helper.c | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/target/ppc/excp_helper.c b/target/ppc/excp_helper.c
index c8b8eca3b1..2e0321ab69 100644
--- a/target/ppc/excp_helper.c
+++ b/target/ppc/excp_helper.c
@@ -1353,12 +1353,26 @@ static bool books_vhyp_handles_hv_excp(PowerPCCPU *cpu)
     return false;
 }
 
+static bool is_prefix_excp(CPUPPCState *env, uint32_t insn)
+{
+    switch (env->excp_model) {
+    case POWERPC_EXCP_970:
+    case POWERPC_EXCP_POWER7:
+    case POWERPC_EXCP_POWER8:
+    case POWERPC_EXCP_POWER9:
+        return false;
+    default: /* POWER10 / ISAv3.1 onward */
+        return ((insn & 0xfc000000) == 0x04000000);
+    }
+}
+
 static void powerpc_excp_books(PowerPCCPU *cpu, int excp)
 {
     CPUState *cs = CPU(cpu);
     CPUPPCState *env = &cpu->env;
     target_ulong msr, new_msr, vector;
     int srr0, srr1, lev = -1;
+    uint32_t insn = 0;
 
     /* new srr1 value excluding must-be-zero bits */
     msr = env->msr & ~0x783f0000ULL;
@@ -1397,6 +1411,29 @@ static void powerpc_excp_books(PowerPCCPU *cpu, int excp)
 
     vector |= env->excp_prefix;
 
+    switch (excp) {
+    case POWERPC_EXCP_MCHECK:
+    case POWERPC_EXCP_DSI:
+    case POWERPC_EXCP_DSEG:
+    case POWERPC_EXCP_ALIGN:
+    case POWERPC_EXCP_PROGRAM:
+    case POWERPC_EXCP_FPU:
+    case POWERPC_EXCP_TRACE:
+    case POWERPC_EXCP_HDSI:
+    case POWERPC_EXCP_HV_EMU:
+    case POWERPC_EXCP_VPU:
+    case POWERPC_EXCP_VSXU:
+    case POWERPC_EXCP_FU:
+    case POWERPC_EXCP_HV_FU:
+        insn = ppc_ldl_code(env, env->nip);
+        if (is_prefix_excp(env, insn)) {
+            msr |= PPC_BIT(34);
+        }
+        break;
+    default:
+        break;
+    }
+
     switch (excp) {
     case POWERPC_EXCP_MCHECK:    /* Machine check exception                  */
         if (!FIELD_EX64(env->msr, MSR, ME)) {
-- 
2.37.2