[RFC PATCH v8 17/23] hw/intc/arm_gicv3: Add NMI handling CPU interface registers

[Jinjie Ruan]

Add the NMIAR CPU interface registers which deal with acknowledging NMI.

When introduce NMI interrupt, there are some updates to the semantics for the
register ICC_IAR1_EL1 and ICC_HPPIR1_EL1. For ICC_IAR1_EL1 register, it
should return 1022 if the intid has super priority. And for ICC_NMIAR1_EL1
register, it should return 1023 if the intid do not have super priority.
Howerever, these are not necessary for ICC_HPPIR1_EL1 register.

Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
v7:
- Add Reviewed-by.
v4:
- Define ICC_NMIAR1_EL1 only if FEAT_GICv3_NMI is implemented.
- Check sctrl_elx.SCTLR_NMI to return 1022 for icc_iar1_read().
- Add gicv3_icc_nmiar1_read() trace event.
- Do not check icc_hppi_can_preempt() for icc_nmiar1_read().
- Add icv_nmiar1_read() and call it when EL2Enabled() and HCR_EL2.IMO == '1'
---
 hw/intc/arm_gicv3_cpuif.c | 59 +++++++++++++++++++++++++++++++++++++--
 hw/intc/gicv3_internal.h  |  1 +
 hw/intc/trace-events      |  1 +
 3 files changed, 58 insertions(+), 3 deletions(-)

diff --git a/hw/intc/arm_gicv3_cpuif.c b/hw/intc/arm_gicv3_cpuif.c
index e1a60d8c15..df82a413c6 100644
--- a/hw/intc/arm_gicv3_cpuif.c
+++ b/hw/intc/arm_gicv3_cpuif.c
@@ -795,6 +795,13 @@ static uint64_t icv_iar_read(CPUARMState *env, const 
ARMCPRegInfo *ri)
     return intid;
 }
 
+static uint64_t icv_nmiar1_read(CPUARMState *env, const ARMCPRegInfo *ri)
+{
+    /* todo */
+    uint64_t intid = INTID_SPURIOUS;
+    return intid;
+}
+
 static uint32_t icc_fullprio_mask(GICv3CPUState *cs)
 {
     /*
@@ -1097,7 +1104,8 @@ static uint64_t icc_hppir0_value(GICv3CPUState *cs, 
CPUARMState *env)
     return cs->hppi.irq;
 }
 
-static uint64_t icc_hppir1_value(GICv3CPUState *cs, CPUARMState *env)
+static uint64_t icc_hppir1_value(GICv3CPUState *cs, CPUARMState *env,
+                                 bool is_nmi, bool is_hppi)
 {
     /* Return the highest priority pending interrupt register value
      * for group 1.
@@ -1108,6 +1116,19 @@ static uint64_t icc_hppir1_value(GICv3CPUState *cs, 
CPUARMState *env)
         return INTID_SPURIOUS;
     }
 
+    if (!is_hppi) {
+        int el = arm_current_el(env);
+
+        if (is_nmi && (!cs->hppi.superprio)) {
+            return INTID_SPURIOUS;
+        }
+
+        if ((!is_nmi) && cs->hppi.superprio
+            && env->cp15.sctlr_el[el] & SCTLR_NMI) {
+            return INTID_NMI;
+        }
+    }
+
     /* Check whether we can return the interrupt or if we should return
      * a special identifier, as per the CheckGroup1ForSpecialIdentifiers
      * pseudocode. (We can simplify a little because for us ICC_SRE_EL1.RM
@@ -1168,7 +1189,7 @@ static uint64_t icc_iar1_read(CPUARMState *env, const 
ARMCPRegInfo *ri)
     if (!icc_hppi_can_preempt(cs)) {
         intid = INTID_SPURIOUS;
     } else {
-        intid = icc_hppir1_value(cs, env);
+        intid = icc_hppir1_value(cs, env, false, false);
     }
 
     if (!gicv3_intid_is_special(intid)) {
@@ -1179,6 +1200,25 @@ static uint64_t icc_iar1_read(CPUARMState *env, const 
ARMCPRegInfo *ri)
     return intid;
 }
 
+static uint64_t icc_nmiar1_read(CPUARMState *env, const ARMCPRegInfo *ri)
+{
+    GICv3CPUState *cs = icc_cs_from_env(env);
+    uint64_t intid;
+
+    if (icv_access(env, HCR_IMO)) {
+        return icv_nmiar1_read(env, ri);
+    }
+
+    intid = icc_hppir1_value(cs, env, true, false);
+
+    if (!gicv3_intid_is_special(intid)) {
+        icc_activate_irq(cs, intid);
+    }
+
+    trace_gicv3_icc_nmiar1_read(gicv3_redist_affid(cs), intid);
+    return intid;
+}
+
 static void icc_drop_prio(GICv3CPUState *cs, int grp)
 {
     /* Drop the priority of the currently active interrupt in
@@ -1555,7 +1595,7 @@ static uint64_t icc_hppir1_read(CPUARMState *env, const 
ARMCPRegInfo *ri)
         return icv_hppir_read(env, ri);
     }
 
-    value = icc_hppir1_value(cs, env);
+    value = icc_hppir1_value(cs, env, false, true);
     trace_gicv3_icc_hppir1_read(gicv3_redist_affid(cs), value);
     return value;
 }
@@ -2482,6 +2522,15 @@ static const ARMCPRegInfo 
gicv3_cpuif_icc_apxr23_reginfo[] = {
     },
 };
 
+static const ARMCPRegInfo gicv3_cpuif_gicv3_nmi_reginfo[] = {
+    { .name = "ICC_NMIAR1_EL1", .state = ARM_CP_STATE_BOTH,
+      .opc0 = 3, .opc1 = 0, .crn = 12, .crm = 9, .opc2 = 5,
+      .type = ARM_CP_IO | ARM_CP_NO_RAW,
+      .access = PL1_R, .accessfn = gicv3_irq_access,
+      .readfn = icc_nmiar1_read,
+    },
+};
+
 static uint64_t ich_ap_read(CPUARMState *env, const ARMCPRegInfo *ri)
 {
     GICv3CPUState *cs = icc_cs_from_env(env);
@@ -2838,6 +2887,10 @@ void gicv3_init_cpuif(GICv3State *s)
          */
         define_arm_cp_regs(cpu, gicv3_cpuif_reginfo);
 
+        if (s->nmi_support) {
+            define_arm_cp_regs(cpu, gicv3_cpuif_gicv3_nmi_reginfo);
+        }
+
         /*
          * The CPU implementation specifies the number of supported
          * bits of physical priority. For backwards compatibility
diff --git a/hw/intc/gicv3_internal.h b/hw/intc/gicv3_internal.h
index 8d793243f4..93e56b3726 100644
--- a/hw/intc/gicv3_internal.h
+++ b/hw/intc/gicv3_internal.h
@@ -511,6 +511,7 @@ FIELD(VTE, RDBASE, 42, RDBASE_PROCNUM_LENGTH)
 /* Special interrupt IDs */
 #define INTID_SECURE 1020
 #define INTID_NONSECURE 1021
+#define INTID_NMI 1022
 #define INTID_SPURIOUS 1023
 
 /* Functions internal to the emulated GICv3 */
diff --git a/hw/intc/trace-events b/hw/intc/trace-events
index 1ef29d0256..94030550d5 100644
--- a/hw/intc/trace-events
+++ b/hw/intc/trace-events
@@ -116,6 +116,7 @@ gicv3_cpuif_set_irqs(uint32_t cpuid, int fiqlevel, int 
irqlevel) "GICv3 CPU i/f
 gicv3_icc_generate_sgi(uint32_t cpuid, int irq, int irm, uint32_t aff, 
uint32_t targetlist) "GICv3 CPU i/f 0x%x generating SGI %d IRM %d target 
affinity 0x%xxx targetlist 0x%x"
 gicv3_icc_iar0_read(uint32_t cpu, uint64_t val) "GICv3 ICC_IAR0 read cpu 0x%x 
value 0x%" PRIx64
 gicv3_icc_iar1_read(uint32_t cpu, uint64_t val) "GICv3 ICC_IAR1 read cpu 0x%x 
value 0x%" PRIx64
+gicv3_icc_nmiar1_read(uint32_t cpu, uint64_t val) "GICv3 ICC_NMIAR1 read cpu 
0x%x value 0x%" PRIx64
 gicv3_icc_eoir_write(int grp, uint32_t cpu, uint64_t val) "GICv3 ICC_EOIR%d 
write cpu 0x%x value 0x%" PRIx64
 gicv3_icc_hppir0_read(uint32_t cpu, uint64_t val) "GICv3 ICC_HPPIR0 read cpu 
0x%x value 0x%" PRIx64
 gicv3_icc_hppir1_read(uint32_t cpu, uint64_t val) "GICv3 ICC_HPPIR1 read cpu 
0x%x value 0x%" PRIx64
-- 
2.34.1