target/riscv: Implement SGEIP bit in hip and hie CSRs

A hypervisor can optionally take guest external interrupts using
SGEIP bit of hip and hie CSRs.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Frank Chang <frank.chang@sifive.com>
Message-id: 20220204174700.534953-3-anup@brainfault.org
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

target/riscv/cpu.c

@@ -434,6 +434,7 @@ static void riscv_cpu_reset(DeviceState *dev)
         }
     }
     env->mcause = 0;
+    env->miclaim = MIP_SGEIP;
     env->pc = env->resetvec;
     env->two_stage_lookup = false;
     /* mmte is supposed to have pm.current hardwired to 1 */
@@ -695,7 +696,7 @@ static void riscv_cpu_init(Object *obj)
     cpu_set_cpustate_pointers(cpu);
 
 #ifndef CONFIG_USER_ONLY
-    qdev_init_gpio_in(DEVICE(cpu), riscv_cpu_set_irq, 12);
+    qdev_init_gpio_in(DEVICE(cpu), riscv_cpu_set_irq, IRQ_LOCAL_MAX);
 #endif /* CONFIG_USER_ONLY */
 }
 

target/riscv/cpu_bits.h

@@ -540,6 +540,8 @@ typedef enum RISCVException {
 #define IRQ_S_EXT                          9
 #define IRQ_VS_EXT                         10
 #define IRQ_M_EXT                          11
+#define IRQ_S_GEXT                         12
+#define IRQ_LOCAL_MAX                      16
 
 /* mip masks */
 #define MIP_USIP                           (1 << IRQ_U_SOFT)
@@ -554,6 +556,7 @@ typedef enum RISCVException {
 #define MIP_SEIP                           (1 << IRQ_S_EXT)
 #define MIP_VSEIP                          (1 << IRQ_VS_EXT)
 #define MIP_MEIP                           (1 << IRQ_M_EXT)
+#define MIP_SGEIP                          (1 << IRQ_S_GEXT)
 
 /* sip masks */
 #define SIP_SSIP                           MIP_SSIP

target/riscv/csr.c

@@ -461,12 +461,13 @@ static RISCVException read_timeh(CPURISCVState *env, int csrno,
 #define M_MODE_INTERRUPTS  (MIP_MSIP | MIP_MTIP | MIP_MEIP)
 #define S_MODE_INTERRUPTS  (MIP_SSIP | MIP_STIP | MIP_SEIP)
 #define VS_MODE_INTERRUPTS (MIP_VSSIP | MIP_VSTIP | MIP_VSEIP)
+#define HS_MODE_INTERRUPTS (MIP_SGEIP | VS_MODE_INTERRUPTS)
 
 static const target_ulong delegable_ints = S_MODE_INTERRUPTS |
                                            VS_MODE_INTERRUPTS;
 static const target_ulong vs_delegable_ints = VS_MODE_INTERRUPTS;
 static const target_ulong all_ints = M_MODE_INTERRUPTS | S_MODE_INTERRUPTS |
-                                     VS_MODE_INTERRUPTS;
+                                     HS_MODE_INTERRUPTS;
 #define DELEGABLE_EXCPS ((1ULL << (RISCV_EXCP_INST_ADDR_MIS)) | \
                          (1ULL << (RISCV_EXCP_INST_ACCESS_FAULT)) | \
                          (1ULL << (RISCV_EXCP_ILLEGAL_INST)) | \
@@ -748,7 +749,7 @@ static RISCVException write_mideleg(CPURISCVState *env, int csrno,
 {
     env->mideleg = (env->mideleg & ~delegable_ints) | (val & delegable_ints);
     if (riscv_has_ext(env, RVH)) {
-        env->mideleg |= VS_MODE_INTERRUPTS;
+        env->mideleg |= HS_MODE_INTERRUPTS;
     }
     return RISCV_EXCP_NONE;
 }
@@ -764,6 +765,9 @@ static RISCVException write_mie(CPURISCVState *env, int csrno,
                                 target_ulong val)
 {
     env->mie = (env->mie & ~all_ints) | (val & all_ints);
+    if (!riscv_has_ext(env, RVH)) {
+        env->mie &= ~MIP_SGEIP;
+    }
     return RISCV_EXCP_NONE;
 }
 
@@ -1110,7 +1114,7 @@ static RISCVException rmw_sip(CPURISCVState *env, int csrno,
     }
 
     if (ret_value) {
-        *ret_value &= env->mideleg;
+        *ret_value &= env->mideleg & S_MODE_INTERRUPTS;
     }
     return ret;
 }
@@ -1228,7 +1232,7 @@ static RISCVException rmw_hvip(CPURISCVState *env, int csrno,
                       write_mask & hvip_writable_mask);
 
     if (ret_value) {
-        *ret_value &= hvip_writable_mask;
+        *ret_value &= VS_MODE_INTERRUPTS;
     }
     return ret;
 }
@@ -1241,22 +1245,22 @@ static RISCVException rmw_hip(CPURISCVState *env, int csrno,
                       write_mask & hip_writable_mask);
 
     if (ret_value) {
-        *ret_value &= hip_writable_mask;
+        *ret_value &= HS_MODE_INTERRUPTS;
     }
     return ret;
 }
 
 static RISCVException read_hie(CPURISCVState *env, int csrno,
                                target_ulong *val)
 {
-    *val = env->mie & VS_MODE_INTERRUPTS;
+    *val = env->mie & HS_MODE_INTERRUPTS;
     return RISCV_EXCP_NONE;
 }
 
 static RISCVException write_hie(CPURISCVState *env, int csrno,
                                 target_ulong val)
 {
-    target_ulong newval = (env->mie & ~VS_MODE_INTERRUPTS) | (val & VS_MODE_INTERRUPTS);
+    target_ulong newval = (env->mie & ~HS_MODE_INTERRUPTS) | (val & HS_MODE_INTERRUPTS);
     return write_mie(env, CSR_MIE, newval);
 }