[PULL 21/38] target/riscv: Add hypvervisor trap support

[Palmer Dabbelt]

From: Alistair Francis <address@hidden>

Signed-off-by: Alistair Francis <address@hidden>
Reviewed-by: Palmer Dabbelt <address@hidden>
Signed-off-by: Palmer Dabbelt <address@hidden>
---
 target/riscv/cpu_helper.c | 69 +++++++++++++++++++++++++++++++++------
 1 file changed, 59 insertions(+), 10 deletions(-)

diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
index a8b114ae16..895b6ca25d 100644
--- a/target/riscv/cpu_helper.c
+++ b/target/riscv/cpu_helper.c
@@ -641,6 +641,8 @@ void riscv_cpu_do_interrupt(CPUState *cs)
 
     RISCVCPU *cpu = RISCV_CPU(cs);
     CPURISCVState *env = &cpu->env;
+    bool force_hs_execp = riscv_cpu_force_hs_excep_enabled(env);
+    target_ulong s;
 
     /* cs->exception is 32-bits wide unlike mcause which is XLEN-bits wide
      * so we mask off the MSB and separate into trap type and cause.
@@ -650,19 +652,14 @@ void riscv_cpu_do_interrupt(CPUState *cs)
     target_ulong deleg = async ? env->mideleg : env->medeleg;
     target_ulong tval = 0;
 
-    static const int ecall_cause_map[] = {
-        [PRV_U] = RISCV_EXCP_U_ECALL,
-        [PRV_S] = RISCV_EXCP_S_ECALL,
-        [PRV_H] = RISCV_EXCP_VS_ECALL,
-        [PRV_M] = RISCV_EXCP_M_ECALL
-    };
-
     if (!async) {
         /* set tval to badaddr for traps with address information */
         switch (cause) {
         case RISCV_EXCP_INST_GUEST_PAGE_FAULT:
         case RISCV_EXCP_LOAD_GUEST_ACCESS_FAULT:
         case RISCV_EXCP_STORE_GUEST_AMO_ACCESS_FAULT:
+            force_hs_execp = true;
+            /* fallthrough */
         case RISCV_EXCP_INST_ADDR_MIS:
         case RISCV_EXCP_INST_ACCESS_FAULT:
         case RISCV_EXCP_LOAD_ADDR_MIS:
@@ -680,7 +677,16 @@ void riscv_cpu_do_interrupt(CPUState *cs)
         /* ecall is dispatched as one cause so translate based on mode */
         if (cause == RISCV_EXCP_U_ECALL) {
             assert(env->priv <= 3);
-            cause = ecall_cause_map[env->priv];
+
+            if (env->priv == PRV_M) {
+                cause = RISCV_EXCP_M_ECALL;
+            } else if (env->priv == PRV_S && riscv_cpu_virt_enabled(env)) {
+                cause = RISCV_EXCP_VS_ECALL;
+            } else if (env->priv == PRV_S && !riscv_cpu_virt_enabled(env)) {
+                cause = RISCV_EXCP_S_ECALL;
+            } else if (env->priv == PRV_U) {
+                cause = RISCV_EXCP_U_ECALL;
+            }
         }
     }
 
@@ -690,7 +696,36 @@ void riscv_cpu_do_interrupt(CPUState *cs)
     if (env->priv <= PRV_S &&
             cause < TARGET_LONG_BITS && ((deleg >> cause) & 1)) {
         /* handle the trap in S-mode */
-        target_ulong s = env->mstatus;
+        if (riscv_has_ext(env, RVH)) {
+            target_ulong hdeleg = async ? env->hideleg : env->hedeleg;
+
+            if (riscv_cpu_virt_enabled(env) && ((hdeleg >> cause) & 1) &&
+                !force_hs_execp) {
+                /* Trap to VS mode */
+            } else if (riscv_cpu_virt_enabled(env)) {
+                /* Trap into HS mode, from virt */
+                riscv_cpu_swap_hypervisor_regs(env);
+                env->hstatus = set_field(env->hstatus, HSTATUS_SP2V,
+                                         get_field(env->hstatus, HSTATUS_SPV));
+                env->hstatus = set_field(env->hstatus, HSTATUS_SP2P,
+                                         get_field(env->mstatus, SSTATUS_SPP));
+                env->hstatus = set_field(env->hstatus, HSTATUS_SPV,
+                                         riscv_cpu_virt_enabled(env));
+
+                riscv_cpu_set_virt_enabled(env, 0);
+                riscv_cpu_set_force_hs_excep(env, 0);
+            } else {
+                /* Trap into HS mode */
+                env->hstatus = set_field(env->hstatus, HSTATUS_SP2V,
+                                         get_field(env->hstatus, HSTATUS_SPV));
+                env->hstatus = set_field(env->hstatus, HSTATUS_SP2P,
+                                         get_field(env->mstatus, SSTATUS_SPP));
+                env->hstatus = set_field(env->hstatus, HSTATUS_SPV,
+                                         riscv_cpu_virt_enabled(env));
+            }
+        }
+
+        s = env->mstatus;
         s = set_field(s, MSTATUS_SPIE, env->priv_ver >= PRIV_VERSION_1_10_0 ?
             get_field(s, MSTATUS_SIE) : get_field(s, MSTATUS_UIE << 
env->priv));
         s = set_field(s, MSTATUS_SPP, env->priv);
@@ -704,7 +739,21 @@ void riscv_cpu_do_interrupt(CPUState *cs)
         riscv_cpu_set_mode(env, PRV_S);
     } else {
         /* handle the trap in M-mode */
-        target_ulong s = env->mstatus;
+        if (riscv_has_ext(env, RVH)) {
+            if (riscv_cpu_virt_enabled(env)) {
+                riscv_cpu_swap_hypervisor_regs(env);
+            }
+            env->mstatus = set_field(env->mstatus, MSTATUS_MPV,
+                                      riscv_cpu_virt_enabled(env));
+            env->mstatus = set_field(env->mstatus, MSTATUS_MTL,
+                                      riscv_cpu_force_hs_excep_enabled(env));
+
+            /* Trapping to M mode, virt is disabled */
+            riscv_cpu_set_virt_enabled(env, 0);
+            riscv_cpu_set_force_hs_excep(env, 0);
+        }
+
+        s = env->mstatus;
         s = set_field(s, MSTATUS_MPIE, env->priv_ver >= PRIV_VERSION_1_10_0 ?
             get_field(s, MSTATUS_MIE) : get_field(s, MSTATUS_UIE << 
env->priv));
         s = set_field(s, MSTATUS_MPP, env->priv);
-- 
2.25.0.265.gbab2e86ba0-goog