hw/intc/arm_gicv3: Implement NMI interrupt priority

If GICD_CTLR_DS bit is zero and the NMI is non-secure, the NMI priority is
higher than 0x80, otherwise it is higher than 0x0. And save the interrupt
non-maskable property in hppi.nmi to deliver NMI exception. Since both GICR
and GICD can deliver NMI, it is both necessary to check whether the pending
irq is NMI in gicv3_redist_update_noirqset and gicv3_update_noirqset.

Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20240407081733.3231820-21-ruanjinjie@huawei.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

hw/intc/arm_gicv3.c

@@ -21,7 +21,7 @@
 #include "hw/intc/arm_gicv3.h"
 #include "gicv3_internal.h"
 
-static bool irqbetter(GICv3CPUState *cs, int irq, uint8_t prio)
+static bool irqbetter(GICv3CPUState *cs, int irq, uint8_t prio, bool nmi)
 {
     /* Return true if this IRQ at this priority should take
      * precedence over the current recorded highest priority
@@ -30,14 +30,23 @@ static bool irqbetter(GICv3CPUState *cs, int irq, uint8_t prio)
      * is the same as this one (a property which the calling code
      * relies on).
      */
-    if (prio < cs->hppi.prio) {
-        return true;
+    if (prio != cs->hppi.prio) {
+        return prio < cs->hppi.prio;
+    }
+
+    /*
+     * The same priority IRQ with non-maskable property should signal to
+     * the CPU as it have the priority higher than the labelled 0x80 or 0x00.
+     */
+    if (nmi != cs->hppi.nmi) {
+        return nmi;
     }
+
     /* If multiple pending interrupts have the same priority then it is an
      * IMPDEF choice which of them to signal to the CPU. We choose to
      * signal the one with the lowest interrupt number.
      */
-    if (prio == cs->hppi.prio && irq <= cs->hppi.irq) {
+    if (irq <= cs->hppi.irq) {
         return true;
     }
     return false;
@@ -129,6 +138,40 @@ static uint32_t gicr_int_pending(GICv3CPUState *cs)
     return pend;
 }
 
+static bool gicv3_get_priority(GICv3CPUState *cs, bool is_redist, int irq,
+                               uint8_t *prio)
+{
+    uint32_t nmi = 0x0;
+
+    if (is_redist) {
+        nmi = extract32(cs->gicr_inmir0, irq, 1);
+    } else {
+        nmi = *gic_bmp_ptr32(cs->gic->nmi, irq);
+        nmi = nmi & (1 << (irq & 0x1f));
+    }
+
+    if (nmi) {
+        /* DS = 0 & Non-secure NMI */
+        if (!(cs->gic->gicd_ctlr & GICD_CTLR_DS) &&
+            ((is_redist && extract32(cs->gicr_igroupr0, irq, 1)) ||
+             (!is_redist && gicv3_gicd_group_test(cs->gic, irq)))) {
+            *prio = 0x80;
+        } else {
+            *prio = 0x0;
+        }
+
+        return true;
+    }
+
+    if (is_redist) {
+        *prio = cs->gicr_ipriorityr[irq];
+    } else {
+        *prio = cs->gic->gicd_ipriority[irq];
+    }
+
+    return false;
+}
+
 /* Update the interrupt status after state in a redistributor
  * or CPU interface has changed, but don't tell the CPU i/f.
  */
@@ -141,6 +184,7 @@ static void gicv3_redist_update_noirqset(GICv3CPUState *cs)
     uint8_t prio;
     int i;
     uint32_t pend;
+    bool nmi = false;
 
     /* Find out which redistributor interrupts are eligible to be
      * signaled to the CPU interface.
@@ -152,10 +196,11 @@ static void gicv3_redist_update_noirqset(GICv3CPUState *cs)
             if (!(pend & (1 << i))) {
                 continue;
             }
-            prio = cs->gicr_ipriorityr[i];
-            if (irqbetter(cs, i, prio)) {
+            nmi = gicv3_get_priority(cs, true, i, &prio);
+            if (irqbetter(cs, i, prio, nmi)) {
                 cs->hppi.irq = i;
                 cs->hppi.prio = prio;
+                cs->hppi.nmi = nmi;
                 seenbetter = true;
             }
         }
@@ -168,9 +213,10 @@ static void gicv3_redist_update_noirqset(GICv3CPUState *cs)
     if ((cs->gicr_ctlr & GICR_CTLR_ENABLE_LPIS) && cs->gic->lpi_enable &&
         (cs->gic->gicd_ctlr & GICD_CTLR_EN_GRP1NS) &&
         (cs->hpplpi.prio != 0xff)) {
-        if (irqbetter(cs, cs->hpplpi.irq, cs->hpplpi.prio)) {
+        if (irqbetter(cs, cs->hpplpi.irq, cs->hpplpi.prio, cs->hpplpi.nmi)) {
             cs->hppi.irq = cs->hpplpi.irq;
             cs->hppi.prio = cs->hpplpi.prio;
+            cs->hppi.nmi = cs->hpplpi.nmi;
             cs->hppi.grp = cs->hpplpi.grp;
             seenbetter = true;
         }
@@ -213,6 +259,7 @@ static void gicv3_update_noirqset(GICv3State *s, int start, int len)
     int i;
     uint8_t prio;
     uint32_t pend = 0;
+    bool nmi = false;
 
     assert(start >= GIC_INTERNAL);
     assert(len > 0);
@@ -240,10 +287,11 @@ static void gicv3_update_noirqset(GICv3State *s, int start, int len)
              */
             continue;
         }
-        prio = s->gicd_ipriority[i];
-        if (irqbetter(cs, i, prio)) {
+        nmi = gicv3_get_priority(cs, false, i, &prio);
+        if (irqbetter(cs, i, prio, nmi)) {
             cs->hppi.irq = i;
             cs->hppi.prio = prio;
+            cs->hppi.nmi = nmi;
             cs->seenbetter = true;
         }
     }
@@ -293,6 +341,7 @@ void gicv3_full_update_noirqset(GICv3State *s)
 
     for (i = 0; i < s->num_cpu; i++) {
         s->cpu[i].hppi.prio = 0xff;
+        s->cpu[i].hppi.nmi = false;
     }
 
     /* Note that we can guarantee that these functions will not

hw/intc/arm_gicv3_common.c

@@ -536,8 +536,11 @@ static void arm_gicv3_common_reset_hold(Object *obj)
         memset(cs->gicr_ipriorityr, 0, sizeof(cs->gicr_ipriorityr));
 
         cs->hppi.prio = 0xff;
+        cs->hppi.nmi = false;
         cs->hpplpi.prio = 0xff;
+        cs->hpplpi.nmi = false;
         cs->hppvlpi.prio = 0xff;
+        cs->hppvlpi.nmi = false;
 
         /* State in the CPU interface must *not* be reset here, because it
          * is part of the CPU's reset domain, not the GIC device's.

hw/intc/arm_gicv3_redist.c

@@ -120,6 +120,7 @@ static void update_for_one_lpi(GICv3CPUState *cs, int irq,
         ((prio == hpp->prio) && (irq <= hpp->irq))) {
         hpp->irq = irq;
         hpp->prio = prio;
+        hpp->nmi = false;
         /* LPIs and vLPIs are always non-secure Grp1 interrupts */
         hpp->grp = GICV3_G1NS;
     }
@@ -156,6 +157,7 @@ static void update_for_all_lpis(GICv3CPUState *cs, uint64_t ptbase,
     int i, bit;
 
     hpp->prio = 0xff;
+    hpp->nmi = false;
 
     for (i = GICV3_LPI_INTID_START / 8; i < pendt_size / 8; i++) {
         address_space_read(as, ptbase + i, MEMTXATTRS_UNSPECIFIED, &pend, 1);
@@ -241,6 +243,7 @@ static void gicv3_redist_update_vlpi_only(GICv3CPUState *cs)
 
     if (!FIELD_EX64(cs->gicr_vpendbaser, GICR_VPENDBASER, VALID)) {
         cs->hppvlpi.prio = 0xff;
+        cs->hppvlpi.nmi = false;
         return;
     }