hw/intc/arm_gicv3: Add NMI handling CPU interface registers

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 non-maskable property. And for
ICC_NMIAR1_EL1 register, it should return 1023 if the intid do not have
non-maskable property. Howerever, these are not necessary for ICC_HPPIR1_EL1
register.

And the APR and RPR has NMI bits which should be handled correctly.

Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
[PMM: Separate out whether cpuif supports NMI from whether the
 GIC proper (IRI) supports NMI]
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20240407081733.3231820-19-ruanjinjie@huawei.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

hw/intc/arm_gicv3_cpuif.c

@@ -21,6 +21,7 @@
 #include "hw/irq.h"
 #include "cpu.h"
 #include "target/arm/cpregs.h"
+#include "target/arm/cpu-features.h"
 #include "sysemu/tcg.h"
 #include "sysemu/qtest.h"
 
@@ -795,6 +796,13 @@ 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)
 {
     /*
@@ -832,6 +840,23 @@ static int icc_highest_active_prio(GICv3CPUState *cs)
      */
     int i;
 
+    if (cs->nmi_support) {
+        /*
+         * If an NMI is active this takes precedence over anything else
+         * for priority purposes; the NMI bit is only in the AP1R0 bit.
+         * We return here the effective priority of the NMI, which is
+         * either 0x0 or 0x80. Callers will need to check NMI again for
+         * purposes of either setting the RPR register bits or for
+         * prioritization of NMI vs non-NMI.
+         */
+        if (cs->icc_apr[GICV3_G1][0] & ICC_AP1R_EL1_NMI) {
+            return 0;
+        }
+        if (cs->icc_apr[GICV3_G1NS][0] & ICC_AP1R_EL1_NMI) {
+            return (cs->gic->gicd_ctlr & GICD_CTLR_DS) ? 0 : 0x80;
+        }
+    }
+
     for (i = 0; i < icc_num_aprs(cs); i++) {
         uint32_t apr = cs->icc_apr[GICV3_G0][i] |
             cs->icc_apr[GICV3_G1][i] | cs->icc_apr[GICV3_G1NS][i];
@@ -898,12 +923,24 @@ static bool icc_hppi_can_preempt(GICv3CPUState *cs)
      */
     int rprio;
     uint32_t mask;
+    ARMCPU *cpu = ARM_CPU(cs->cpu);
+    CPUARMState *env = &cpu->env;
 
     if (icc_no_enabled_hppi(cs)) {
         return false;
     }
 
-    if (cs->hppi.prio >= cs->icc_pmr_el1) {
+    if (cs->hppi.nmi) {
+        if (!(cs->gic->gicd_ctlr & GICD_CTLR_DS) &&
+            cs->hppi.grp == GICV3_G1NS) {
+            if (cs->icc_pmr_el1 < 0x80) {
+                return false;
+            }
+            if (arm_is_secure(env) && cs->icc_pmr_el1 == 0x80) {
+                return false;
+            }
+        }
+    } else if (cs->hppi.prio >= cs->icc_pmr_el1) {
         /* Priority mask masks this interrupt */
         return false;
     }
@@ -923,6 +960,12 @@ static bool icc_hppi_can_preempt(GICv3CPUState *cs)
         return true;
     }
 
+    if (cs->hppi.nmi && (cs->hppi.prio & mask) == (rprio & mask)) {
+        if (!(cs->icc_apr[cs->hppi.grp][0] & ICC_AP1R_EL1_NMI)) {
+            return true;
+        }
+    }
+
     return false;
 }
 
@@ -1044,8 +1087,13 @@ static void icc_activate_irq(GICv3CPUState *cs, int irq)
     int aprbit = prio >> (8 - cs->prebits);
     int regno = aprbit / 32;
     int regbit = aprbit % 32;
+    bool nmi = cs->hppi.nmi;
 
-    cs->icc_apr[cs->hppi.grp][regno] |= (1 << regbit);
+    if (nmi) {
+        cs->icc_apr[cs->hppi.grp][regno] |= ICC_AP1R_EL1_NMI;
+    } else {
+        cs->icc_apr[cs->hppi.grp][regno] |= (1 << regbit);
+    }
 
     if (irq < GIC_INTERNAL) {
         cs->gicr_iactiver0 = deposit32(cs->gicr_iactiver0, irq, 1, 1);
@@ -1159,6 +1207,7 @@ static uint64_t icc_iar0_read(CPUARMState *env, const ARMCPRegInfo *ri)
 static uint64_t icc_iar1_read(CPUARMState *env, const ARMCPRegInfo *ri)
 {
     GICv3CPUState *cs = icc_cs_from_env(env);
+    int el = arm_current_el(env);
     uint64_t intid;
 
     if (icv_access(env, HCR_IMO)) {
@@ -1172,13 +1221,44 @@ static uint64_t icc_iar1_read(CPUARMState *env, const ARMCPRegInfo *ri)
     }
 
     if (!gicv3_intid_is_special(intid)) {
-        icc_activate_irq(cs, intid);
+        if (cs->hppi.nmi && env->cp15.sctlr_el[el] & SCTLR_NMI) {
+            intid = INTID_NMI;
+        } else {
+            icc_activate_irq(cs, intid);
+        }
     }
 
     trace_gicv3_icc_iar1_read(gicv3_redist_affid(cs), intid);
     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);
+    }
+
+    if (!icc_hppi_can_preempt(cs)) {
+        intid = INTID_SPURIOUS;
+    } else {
+        intid = icc_hppir1_value(cs, env);
+    }
+
+    if (!gicv3_intid_is_special(intid)) {
+        if (!cs->hppi.nmi) {
+            intid = INTID_SPURIOUS;
+        } else {
+            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
@@ -1205,6 +1285,12 @@ static void icc_drop_prio(GICv3CPUState *cs, int grp)
         if (!*papr) {
             continue;
         }
+
+        if (i == 0 && cs->nmi_support && (*papr & ICC_AP1R_EL1_NMI)) {
+            *papr &= (~ICC_AP1R_EL1_NMI);
+            break;
+        }
+
         /* Clear the lowest set bit */
         *papr &= *papr - 1;
         break;
@@ -1239,6 +1325,15 @@ static int icc_highest_active_group(GICv3CPUState *cs)
      */
     int i;
 
+    if (cs->nmi_support) {
+        if (cs->icc_apr[GICV3_G1][0] & ICC_AP1R_EL1_NMI) {
+            return GICV3_G1;
+        }
+        if (cs->icc_apr[GICV3_G1NS][0] & ICC_AP1R_EL1_NMI) {
+            return GICV3_G1NS;
+        }
+    }
+
     for (i = 0; i < ARRAY_SIZE(cs->icc_apr[0]); i++) {
         int g0ctz = ctz32(cs->icc_apr[GICV3_G0][i]);
         int g1ctz = ctz32(cs->icc_apr[GICV3_G1][i]);
@@ -1693,7 +1788,11 @@ static void icc_ap_write(CPUARMState *env, const ARMCPRegInfo *ri,
         return;
     }
 
-    cs->icc_apr[grp][regno] = value & 0xFFFFFFFFU;
+    if (cs->nmi_support) {
+        cs->icc_apr[grp][regno] = value & (0xFFFFFFFFU | ICC_AP1R_EL1_NMI);
+    } else {
+        cs->icc_apr[grp][regno] = value & 0xFFFFFFFFU;
+    }
     gicv3_cpuif_update(cs);
 }
 
@@ -1783,7 +1882,7 @@ static void icc_dir_write(CPUARMState *env, const ARMCPRegInfo *ri,
 static uint64_t icc_rpr_read(CPUARMState *env, const ARMCPRegInfo *ri)
 {
     GICv3CPUState *cs = icc_cs_from_env(env);
-    int prio;
+    uint64_t prio;
 
     if (icv_access(env, HCR_FMO | HCR_IMO)) {
         return icv_rpr_read(env, ri);
@@ -1803,6 +1902,22 @@ static uint64_t icc_rpr_read(CPUARMState *env, const ARMCPRegInfo *ri)
         }
     }
 
+    if (cs->nmi_support) {
+        /* NMI info is reported in the high bits of RPR */
+        if (arm_feature(env, ARM_FEATURE_EL3) && !arm_is_secure(env)) {
+            if (cs->icc_apr[GICV3_G1NS][0] & ICC_AP1R_EL1_NMI) {
+                prio |= ICC_RPR_EL1_NMI;
+            }
+        } else {
+            if (cs->icc_apr[GICV3_G1NS][0] & ICC_AP1R_EL1_NMI) {
+                prio |= ICC_RPR_EL1_NSNMI;
+            }
+            if (cs->icc_apr[GICV3_G1][0] & ICC_AP1R_EL1_NMI) {
+                prio |= ICC_RPR_EL1_NMI;
+            }
+        }
+    }
+
     trace_gicv3_icc_rpr_read(gicv3_redist_affid(cs), prio);
     return prio;
 }
@@ -2482,6 +2597,15 @@ 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 +2962,19 @@ void gicv3_init_cpuif(GICv3State *s)
          */
         define_arm_cp_regs(cpu, gicv3_cpuif_reginfo);
 
+        /*
+         * If the CPU implements FEAT_NMI and FEAT_GICv3 it must also
+         * implement FEAT_GICv3_NMI, which is the CPU interface part
+         * of NMI support. This is distinct from whether the GIC proper
+         * (redistributors and distributor) have NMI support. In QEMU
+         * that is a property of the GIC device in s->nmi_support;
+         * cs->nmi_support indicates the CPU interface's support.
+         */
+        if (cpu_isar_feature(aa64_nmi, cpu)) {
+            cs->nmi_support = true;
+            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

hw/intc/gicv3_internal.h

@@ -194,6 +194,10 @@ FIELD(GICR_VPENDBASER, VALID, 63, 1)
 #define ICC_CTLR_EL3_A3V (1U << 15)
 #define ICC_CTLR_EL3_NDS (1U << 17)
 
+#define ICC_AP1R_EL1_NMI (1ULL << 63)
+#define ICC_RPR_EL1_NSNMI (1ULL << 62)
+#define ICC_RPR_EL1_NMI (1ULL << 63)
+
 #define ICH_VMCR_EL2_VENG0_SHIFT 0
 #define ICH_VMCR_EL2_VENG0 (1U << ICH_VMCR_EL2_VENG0_SHIFT)
 #define ICH_VMCR_EL2_VENG1_SHIFT 1
@@ -511,6 +515,7 @@ 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 */

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

include/hw/intc/arm_gicv3_common.h

@@ -225,6 +225,13 @@ struct GICv3CPUState {
 
     /* This is temporary working state, to avoid a malloc in gicv3_update() */
     bool seenbetter;
+
+    /*
+     * Whether the CPU interface has NMI support (FEAT_GICv3_NMI). The
+     * CPU interface may support NMIs even when the GIC proper (what the
+     * spec calls the IRI; the redistributors and distributor) does not.
+     */
+    bool nmi_support;
 };
 
 /*