[PATCH 1/2] target/riscv: fix VS interrupts forwarding to HS

[Jose Martins]

VS interrupts (2, 6, 10) were not correctly forwarded to hs-mode when
not delegated in hideleg (which was not being taken into account). This
was mainly because hs level sie was not always considered enabled when
it should. The spec states that "Interrupts for higher-privilege modes,
y>x, are always globally enabled regardless of the setting of the global
yIE bit for the higher-privilege mode." and also "For purposes of
interrupt global enables, HS-mode is considered more privileged than
VS-mode, and VS-mode is considered more privileged than VU-mode". Also,
vs-level interrupts were not being taken into account unless V=1, but
should be unless delegated.

Finally, there is no need for a special case for to handle vs interrupts
as the current privilege level, the state of the global ie and of the
delegation registers should be enough to route all interrupts to the
appropriate privilege level in riscv_cpu_do_interrupt.

Signed-off-by: Jose Martins <josemartin...@gmail.com>
---
 target/riscv/cpu_helper.c | 28 ++++++++--------------------
 1 file changed, 8 insertions(+), 20 deletions(-)

diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
index 21c54ef561..592d4642be 100644
--- a/target/riscv/cpu_helper.c
+++ b/target/riscv/cpu_helper.c
@@ -38,36 +38,24 @@ int riscv_cpu_mmu_index(CPURISCVState *env, bool ifetch)
 #ifndef CONFIG_USER_ONLY
 static int riscv_cpu_local_irq_pending(CPURISCVState *env)
 {
-    target_ulong irqs;
+    target_ulong virt_enabled = riscv_cpu_virt_enabled(env);
 
     target_ulong mstatus_mie = get_field(env->mstatus, MSTATUS_MIE);
     target_ulong mstatus_sie = get_field(env->mstatus, MSTATUS_SIE);
-    target_ulong hs_mstatus_sie = get_field(env->mstatus_hs, MSTATUS_SIE);
 
-    target_ulong pending = env->mip & env->mie &
-                               ~(MIP_VSSIP | MIP_VSTIP | MIP_VSEIP);
-    target_ulong vspending = (env->mip & env->mie &
-                              (MIP_VSSIP | MIP_VSTIP | MIP_VSEIP));
+    target_ulong pending = env->mip & env->mie;
 
     target_ulong mie    = env->priv < PRV_M ||
                           (env->priv == PRV_M && mstatus_mie);
     target_ulong sie    = env->priv < PRV_S ||
                           (env->priv == PRV_S && mstatus_sie);
-    target_ulong hs_sie = env->priv < PRV_S ||
-                          (env->priv == PRV_S && hs_mstatus_sie);
+    target_ulong hsie   = virt_enabled || sie;
+    target_ulong vsie   = virt_enabled && sie;
 
-    if (riscv_cpu_virt_enabled(env)) {
-        target_ulong pending_hs_irq = pending & -hs_sie;
-
-        if (pending_hs_irq) {
-            riscv_cpu_set_force_hs_excep(env, FORCE_HS_EXCEP);
-            return ctz64(pending_hs_irq);
-        }
-
-        pending = vspending;
-    }
-
-    irqs = (pending & ~env->mideleg & -mie) | (pending &  env->mideleg & -sie);
+    target_ulong irqs =
+            (pending & ~env->mideleg & -mie) |
+            (pending &  env->mideleg & ~env->hideleg & -hsie) |
+            (pending &  env->mideleg &  env->hideleg & -vsie);
 
     if (irqs) {
         return ctz64(irqs); /* since non-zero */
-- 
2.30.2