target/riscv: Implement hgeie and hgeip CSRs

The hgeie and hgeip CSRs are required for emulating an external
interrupt controller capable of injecting virtual external interrupt
to Guest/VM running at VS-level.

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: 20220204174700.534953-4-anup@brainfault.org
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

6 files changed, 121 insertions, 38 deletions

diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index e1224d2..f1c2684 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -663,27 +663,53 @@ static void riscv_cpu_realize(DeviceState *dev, Error **errp)
 static void riscv_cpu_set_irq(void *opaque, int irq, int level)
 {
     RISCVCPU *cpu = RISCV_CPU(opaque);
+    CPURISCVState *env = &cpu->env;
 
-    switch (irq) {
-    case IRQ_U_SOFT:
-    case IRQ_S_SOFT:
-    case IRQ_VS_SOFT:
-    case IRQ_M_SOFT:
-    case IRQ_U_TIMER:
-    case IRQ_S_TIMER:
-    case IRQ_VS_TIMER:
-    case IRQ_M_TIMER:
-    case IRQ_U_EXT:
-    case IRQ_S_EXT:
-    case IRQ_VS_EXT:
-    case IRQ_M_EXT:
-        if (kvm_enabled()) {
-            kvm_riscv_set_irq(cpu, irq, level);
-        } else {
-            riscv_cpu_update_mip(cpu, 1 << irq, BOOL_TO_MASK(level));
+    if (irq < IRQ_LOCAL_MAX) {
+        switch (irq) {
+        case IRQ_U_SOFT:
+        case IRQ_S_SOFT:
+        case IRQ_VS_SOFT:
+        case IRQ_M_SOFT:
+        case IRQ_U_TIMER:
+        case IRQ_S_TIMER:
+        case IRQ_VS_TIMER:
+        case IRQ_M_TIMER:
+        case IRQ_U_EXT:
+        case IRQ_S_EXT:
+        case IRQ_VS_EXT:
+        case IRQ_M_EXT:
+             if (kvm_enabled()) {
+                kvm_riscv_set_irq(cpu, irq, level);
+             } else {
+                riscv_cpu_update_mip(cpu, 1 << irq, BOOL_TO_MASK(level));
+             }
+             break;
+        default:
+            g_assert_not_reached();
         }
-        break;
-    default:
+    } else if (irq < (IRQ_LOCAL_MAX + IRQ_LOCAL_GUEST_MAX)) {
+        /* Require H-extension for handling guest local interrupts */
+        if (!riscv_has_ext(env, RVH)) {
+            g_assert_not_reached();
+        }
+
+        /* Compute bit position in HGEIP CSR */
+        irq = irq - IRQ_LOCAL_MAX + 1;
+        if (env->geilen < irq) {
+            g_assert_not_reached();
+        }
+
+        /* Update HGEIP CSR */
+        env->hgeip &= ~((target_ulong)1 << irq);
+        if (level) {
+            env->hgeip |= (target_ulong)1 << irq;
+        }
+
+        /* Update mip.SGEIP bit */
+        riscv_cpu_update_mip(cpu, MIP_SGEIP,
+                             BOOL_TO_MASK(!!(env->hgeie & env->hgeip)));
+    } else {
         g_assert_not_reached();
     }
 }
@@ -696,7 +722,8 @@ 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, IRQ_LOCAL_MAX);
+    qdev_init_gpio_in(DEVICE(cpu), riscv_cpu_set_irq,
+                      IRQ_LOCAL_MAX + IRQ_LOCAL_GUEST_MAX);
 #endif /* CONFIG_USER_ONLY */
 }
 
diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index aacc997..f030cb5 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -161,6 +161,7 @@ struct CPURISCVState {
     target_ulong priv;
     /* This contains QEMU specific information about the virt state. */
     target_ulong virt;
+    target_ulong geilen;
     target_ulong resetvec;
 
     target_ulong mhartid;
@@ -198,6 +199,8 @@ struct CPURISCVState {
     target_ulong htval;
     target_ulong htinst;
     target_ulong hgatp;
+    target_ulong hgeie;
+    target_ulong hgeip;
     uint64_t htimedelta;
 
     /* Upper 64-bits of 128-bit CSRs */
@@ -391,6 +394,8 @@ int riscv_cpu_write_elf32_note(WriteCoreDumpFunction f, CPUState *cs,
 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);
 bool riscv_cpu_fp_enabled(CPURISCVState *env);
+target_ulong riscv_cpu_get_geilen(CPURISCVState *env);
+void riscv_cpu_set_geilen(CPURISCVState *env, target_ulong geilen);
 bool riscv_cpu_vector_enabled(CPURISCVState *env);
 bool riscv_cpu_virt_enabled(CPURISCVState *env);
 void riscv_cpu_set_virt_enabled(CPURISCVState *env, bool enable);
diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
index e1256a9..a541705 100644
--- a/target/riscv/cpu_bits.h
+++ b/target/riscv/cpu_bits.h
@@ -542,6 +542,7 @@ typedef enum RISCVException {
 #define IRQ_M_EXT                          11
 #define IRQ_S_GEXT                         12
 #define IRQ_LOCAL_MAX                      16
+#define IRQ_LOCAL_GUEST_MAX                (TARGET_LONG_BITS - 1)
 
 /* mip masks */
 #define MIP_USIP                           (1 << IRQ_U_SOFT)
diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
index 327a2c4..698389b 100644
--- a/target/riscv/cpu_helper.c
+++ b/target/riscv/cpu_helper.c
@@ -159,7 +159,11 @@ static int riscv_cpu_local_irq_pending(CPURISCVState *env)
     target_ulong mstatus_mie = get_field(env->mstatus, MSTATUS_MIE);
     target_ulong mstatus_sie = get_field(env->mstatus, MSTATUS_SIE);
 
-    target_ulong pending = env->mip & env->mie;
+    target_ulong vsgemask =
+                (target_ulong)1 << get_field(env->hstatus, HSTATUS_VGEIN);
+    target_ulong vsgein = (env->hgeip & vsgemask) ? MIP_VSEIP : 0;
+
+    target_ulong pending = (env->mip | vsgein) & env->mie;
 
     target_ulong mie    = env->priv < PRV_M ||
                           (env->priv == PRV_M && mstatus_mie);
@@ -279,6 +283,28 @@ void riscv_cpu_swap_hypervisor_regs(CPURISCVState *env)
     }
 }
 
+target_ulong riscv_cpu_get_geilen(CPURISCVState *env)
+{
+    if (!riscv_has_ext(env, RVH)) {
+        return 0;
+    }
+
+    return env->geilen;
+}
+
+void riscv_cpu_set_geilen(CPURISCVState *env, target_ulong geilen)
+{
+    if (!riscv_has_ext(env, RVH)) {
+        return;
+    }
+
+    if (geilen > (TARGET_LONG_BITS - 1)) {
+        return;
+    }
+
+    env->geilen = geilen;
+}
+
 bool riscv_cpu_virt_enabled(CPURISCVState *env)
 {
     if (!riscv_has_ext(env, RVH)) {
@@ -322,9 +348,14 @@ uint32_t riscv_cpu_update_mip(RISCVCPU *cpu, uint32_t mask, uint32_t value)
 {
     CPURISCVState *env = &cpu->env;
     CPUState *cs = CPU(cpu);
-    uint32_t old = env->mip;
+    uint32_t gein, vsgein = 0, old = env->mip;
     bool locked = false;
 
+    if (riscv_cpu_virt_enabled(env)) {
+        gein = get_field(env->hstatus, HSTATUS_VGEIN);
+        vsgein = (env->hgeip & (1ULL << gein)) ? MIP_VSEIP : 0;
+    }
+
     if (!qemu_mutex_iothread_locked()) {
         locked = true;
         qemu_mutex_lock_iothread();
@@ -332,7 +363,7 @@ uint32_t riscv_cpu_update_mip(RISCVCPU *cpu, uint32_t mask, uint32_t value)
 
     env->mip = (env->mip & ~mask) | (value & mask);
 
-    if (env->mip) {
+    if (env->mip | vsgein) {
         cpu_interrupt(cs, CPU_INTERRUPT_HARD);
     } else {
         cpu_reset_interrupt(cs, CPU_INTERRUPT_HARD);
diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index c635ffb..b23195b 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -883,7 +883,7 @@ static RISCVException rmw_mip(CPURISCVState *env, int csrno,
     RISCVCPU *cpu = env_archcpu(env);
     /* Allow software control of delegable interrupts not claimed by hardware */
     target_ulong mask = write_mask & delegable_ints & ~env->miclaim;
-    uint32_t old_mip;
+    uint32_t gin, old_mip;
 
     if (mask) {
         old_mip = riscv_cpu_update_mip(cpu, mask, (new_value & mask));
@@ -891,6 +891,11 @@ static RISCVException rmw_mip(CPURISCVState *env, int csrno,
         old_mip = env->mip;
     }
 
+    if (csrno != CSR_HVIP) {
+        gin = get_field(env->hstatus, HSTATUS_VGEIN);
+        old_mip |= (env->hgeip & ((target_ulong)1 << gin)) ? MIP_VSEIP : 0;
+    }
+
     if (ret_value) {
         *ret_value = old_mip;
     }
@@ -1089,7 +1094,7 @@ static RISCVException rmw_vsip(CPURISCVState *env, int csrno,
                                target_ulong new_value, target_ulong write_mask)
 {
     /* Shift the S bits to their VS bit location in mip */
-    int ret = rmw_mip(env, 0, ret_value, new_value << 1,
+    int ret = rmw_mip(env, csrno, ret_value, new_value << 1,
                       (write_mask << 1) & vsip_writable_mask & env->hideleg);
 
     if (ret_value) {
@@ -1109,7 +1114,7 @@ static RISCVException rmw_sip(CPURISCVState *env, int csrno,
     if (riscv_cpu_virt_enabled(env)) {
         ret = rmw_vsip(env, CSR_VSIP, ret_value, new_value, write_mask);
     } else {
-        ret = rmw_mip(env, CSR_MSTATUS, ret_value, new_value,
+        ret = rmw_mip(env, csrno, ret_value, new_value,
                       write_mask & env->mideleg & sip_writable_mask);
     }
 
@@ -1228,7 +1233,7 @@ static RISCVException rmw_hvip(CPURISCVState *env, int csrno,
                                target_ulong *ret_value,
                                target_ulong new_value, target_ulong write_mask)
 {
-    int ret = rmw_mip(env, 0, ret_value, new_value,
+    int ret = rmw_mip(env, csrno, ret_value, new_value,
                       write_mask & hvip_writable_mask);
 
     if (ret_value) {
@@ -1241,7 +1246,7 @@ static RISCVException rmw_hip(CPURISCVState *env, int csrno,
                               target_ulong *ret_value,
                               target_ulong new_value, target_ulong write_mask)
 {
-    int ret = rmw_mip(env, 0, ret_value, new_value,
+    int ret = rmw_mip(env, csrno, ret_value, new_value,
                       write_mask & hip_writable_mask);
 
     if (ret_value) {
@@ -1278,15 +1283,27 @@ static RISCVException write_hcounteren(CPURISCVState *env, int csrno,
     return RISCV_EXCP_NONE;
 }
 
-static RISCVException write_hgeie(CPURISCVState *env, int csrno,
-                                  target_ulong val)
+static RISCVException read_hgeie(CPURISCVState *env, int csrno,
+                                 target_ulong *val)
 {
     if (val) {
-        qemu_log_mask(LOG_UNIMP, "No support for a non-zero GEILEN.");
+        *val = env->hgeie;
     }
     return RISCV_EXCP_NONE;
 }
 
+static RISCVException write_hgeie(CPURISCVState *env, int csrno,
+                                  target_ulong val)
+{
+    /* Only GEILEN:1 bits implemented and BIT0 is never implemented */
+    val &= ((((target_ulong)1) << env->geilen) - 1) << 1;
+    env->hgeie = val;
+    /* Update mip.SGEIP bit */
+    riscv_cpu_update_mip(env_archcpu(env), MIP_SGEIP,
+                         BOOL_TO_MASK(!!(env->hgeie & env->hgeip)));
+    return RISCV_EXCP_NONE;
+}
+
 static RISCVException read_htval(CPURISCVState *env, int csrno,
                                  target_ulong *val)
 {
@@ -1314,11 +1331,11 @@ static RISCVException write_htinst(CPURISCVState *env, int csrno,
     return RISCV_EXCP_NONE;
 }
 
-static RISCVException write_hgeip(CPURISCVState *env, int csrno,
-                                  target_ulong val)
+static RISCVException read_hgeip(CPURISCVState *env, int csrno,
+                                 target_ulong *val)
 {
     if (val) {
-        qemu_log_mask(LOG_UNIMP, "No support for a non-zero GEILEN.");
+        *val = env->hgeip;
     }
     return RISCV_EXCP_NONE;
 }
@@ -2148,10 +2165,10 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
     [CSR_HIP]         = { "hip",         hmode,   NULL,   NULL,     rmw_hip           },
     [CSR_HIE]         = { "hie",         hmode,   read_hie,         write_hie         },
     [CSR_HCOUNTEREN]  = { "hcounteren",  hmode,   read_hcounteren,  write_hcounteren  },
-    [CSR_HGEIE]       = { "hgeie",       hmode,   read_zero,        write_hgeie       },
+    [CSR_HGEIE]       = { "hgeie",       hmode,   read_hgeie,       write_hgeie       },
     [CSR_HTVAL]       = { "htval",       hmode,   read_htval,       write_htval       },
     [CSR_HTINST]      = { "htinst",      hmode,   read_htinst,      write_htinst      },
-    [CSR_HGEIP]       = { "hgeip",       hmode,   read_zero,        write_hgeip       },
+    [CSR_HGEIP]       = { "hgeip",       hmode,   read_hgeip,       NULL              },
     [CSR_HGATP]       = { "hgatp",       hmode,   read_hgatp,       write_hgatp       },
     [CSR_HTIMEDELTA]  = { "htimedelta",  hmode,   read_htimedelta,  write_htimedelta  },
     [CSR_HTIMEDELTAH] = { "htimedeltah", hmode32, read_htimedeltah, write_htimedeltah },
diff --git a/target/riscv/machine.c b/target/riscv/machine.c
index 740e11f..7d72c2d 100644
--- a/target/riscv/machine.c
+++ b/target/riscv/machine.c
@@ -78,8 +78,8 @@ static bool hyper_needed(void *opaque)
 
 static const VMStateDescription vmstate_hyper = {
     .name = "cpu/hyper",
-    .version_id = 1,
-    .minimum_version_id = 1,
+    .version_id = 2,
+    .minimum_version_id = 2,
     .needed = hyper_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINTTL(env.hstatus, RISCVCPU),
@@ -89,6 +89,8 @@ static const VMStateDescription vmstate_hyper = {
         VMSTATE_UINTTL(env.htval, RISCVCPU),
         VMSTATE_UINTTL(env.htinst, RISCVCPU),
         VMSTATE_UINTTL(env.hgatp, RISCVCPU),
+        VMSTATE_UINTTL(env.hgeie, RISCVCPU),
+        VMSTATE_UINTTL(env.hgeip, RISCVCPU),
         VMSTATE_UINT64(env.htimedelta, RISCVCPU),
 
         VMSTATE_UINT64(env.vsstatus, RISCVCPU),