target/riscv: Wake on VS-level external interrupts

Whether or not VSEIP is pending isn't reflected in env->mip and must
instead be determined from hstatus.vgein and hgeip. As a result a
CPU in WFI won't wake on a VSEIP, which violates the WFI behavior as
specified in the privileged ISA. Just use riscv_cpu_all_pending()
instead, which already accounts for VSEIP.

Signed-off-by: Andrew Bresticker <abrestic@rivosinc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20220531210544.181322-1-abrestic@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

target/riscv/cpu.c

@@ -391,7 +391,7 @@ static bool riscv_cpu_has_work(CPUState *cs)
      * Definition of the WFI instruction requires it to ignore the privilege
      * mode and delegation registers, but respect individual enables
      */
-    return (env->mip & env->mie) != 0;
+    return riscv_cpu_all_pending(env) != 0;
 #else
     return true;
 #endif

target/riscv/cpu.h

@@ -489,6 +489,7 @@ int riscv_cpu_gdb_read_register(CPUState *cpu, GByteArray *buf, int reg);
 int riscv_cpu_gdb_write_register(CPUState *cpu, uint8_t *buf, int reg);
 int riscv_cpu_hviprio_index2irq(int index, int *out_irq, int *out_rdzero);
 uint8_t riscv_cpu_default_priority(int irq);
+uint64_t riscv_cpu_all_pending(CPURISCVState *env);
 int riscv_cpu_mirq_pending(CPURISCVState *env);
 int riscv_cpu_sirq_pending(CPURISCVState *env);
 int riscv_cpu_vsirq_pending(CPURISCVState *env);

target/riscv/cpu_helper.c

@@ -340,7 +340,7 @@ static int riscv_cpu_pending_to_irq(CPURISCVState *env,
     return best_irq;
 }
 
-static uint64_t riscv_cpu_all_pending(CPURISCVState *env)
+uint64_t riscv_cpu_all_pending(CPURISCVState *env)
 {
     uint32_t gein = get_field(env->hstatus, HSTATUS_VGEIN);
     uint64_t vsgein = (env->hgeip & (1ULL << gein)) ? MIP_VSEIP : 0;