hw/arm/smmuv3: Add GBPA register

GBPA register can be used to globally abort all
transactions.

It is described in the SMMU manual in "6.3.14 SMMU_GBPA".
ABORT reset value is IMPLEMENTATION DEFINED, it is chosen to
be zero(Do not abort incoming transactions).

Other fields have default values of Use Incoming.

If UPDATE is not set, the write is ignored. This is the only permitted
behavior in SMMUv3.2 and later.(6.3.14.1 Update procedure)

As this patch adds a new state to the SMMU (GBPA), it is added
in a new subsection for forward migration compatibility.
GBPA is only migrated if its value is different from the reset value.
It does this to be backward migration compatible if SW didn't write
the register.

Signed-off-by: Mostafa Saleh <smostafa@google.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Message-id: 20230214094009.2445653-1-smostafa@google.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

hw/arm/smmuv3-internal.h

@@ -79,6 +79,13 @@ REG32(CR0ACK,              0x24)
 REG32(CR1,                 0x28)
 REG32(CR2,                 0x2c)
 REG32(STATUSR,             0x40)
+REG32(GBPA,                0x44)
+    FIELD(GBPA, ABORT,        20, 1)
+    FIELD(GBPA, UPDATE,       31, 1)
+
+/* Use incoming. */
+#define SMMU_GBPA_RESET_VAL 0x1000
+
 REG32(IRQ_CTRL,            0x50)
     FIELD(IRQ_CTRL, GERROR_IRQEN,        0, 1)
     FIELD(IRQ_CTRL, PRI_IRQEN,           1, 1)

hw/arm/smmuv3.c

@@ -285,6 +285,7 @@ static void smmuv3_init_regs(SMMUv3State *s)
     s->gerror = 0;
     s->gerrorn = 0;
     s->statusr = 0;
+    s->gbpa = SMMU_GBPA_RESET_VAL;
 }
 
 static int smmu_get_ste(SMMUv3State *s, dma_addr_t addr, STE *buf,
@@ -659,7 +660,11 @@ static IOMMUTLBEntry smmuv3_translate(IOMMUMemoryRegion *mr, hwaddr addr,
     qemu_mutex_lock(&s->mutex);
 
     if (!smmu_enabled(s)) {
-        status = SMMU_TRANS_DISABLE;
+        if (FIELD_EX32(s->gbpa, GBPA, ABORT)) {
+            status = SMMU_TRANS_ABORT;
+        } else {
+            status = SMMU_TRANS_DISABLE;
+        }
         goto epilogue;
     }
 
@@ -1170,6 +1175,16 @@ static MemTxResult smmu_writel(SMMUv3State *s, hwaddr offset,
     case A_GERROR_IRQ_CFG2:
         s->gerror_irq_cfg2 = data;
         return MEMTX_OK;
+    case A_GBPA:
+        /*
+         * If UPDATE is not set, the write is ignored. This is the only
+         * permitted behavior in SMMUv3.2 and later.
+         */
+        if (data & R_GBPA_UPDATE_MASK) {
+            /* Ignore update bit as write is synchronous. */
+            s->gbpa = data & ~R_GBPA_UPDATE_MASK;
+        }
+        return MEMTX_OK;
     case A_STRTAB_BASE: /* 64b */
         s->strtab_base = deposit64(s->strtab_base, 0, 32, data);
         return MEMTX_OK;
@@ -1318,6 +1333,9 @@ static MemTxResult smmu_readl(SMMUv3State *s, hwaddr offset,
     case A_STATUSR:
         *data = s->statusr;
         return MEMTX_OK;
+    case A_GBPA:
+        *data = s->gbpa;
+        return MEMTX_OK;
     case A_IRQ_CTRL:
     case A_IRQ_CTRL_ACK:
         *data = s->irq_ctrl;
@@ -1482,6 +1500,25 @@ static const VMStateDescription vmstate_smmuv3_queue = {
     },
 };
 
+static bool smmuv3_gbpa_needed(void *opaque)
+{
+    SMMUv3State *s = opaque;
+
+    /* Only migrate GBPA if it has different reset value. */
+    return s->gbpa != SMMU_GBPA_RESET_VAL;
+}
+
+static const VMStateDescription vmstate_gbpa = {
+    .name = "smmuv3/gbpa",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = smmuv3_gbpa_needed,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT32(gbpa, SMMUv3State),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 static const VMStateDescription vmstate_smmuv3 = {
     .name = "smmuv3",
     .version_id = 1,
@@ -1512,6 +1549,10 @@ static const VMStateDescription vmstate_smmuv3 = {
 
         VMSTATE_END_OF_LIST(),
     },
+    .subsections = (const VMStateDescription * []) {
+        &vmstate_gbpa,
+        NULL
+    }
 };
 
 static void smmuv3_instance_init(Object *obj)

include/hw/arm/smmuv3.h

@@ -45,6 +45,7 @@ struct SMMUv3State {
     uint32_t cr[3];
     uint32_t cr0ack;
     uint32_t statusr;
+    uint32_t gbpa;
     uint32_t irq_ctrl;
     uint32_t gerror;
     uint32_t gerrorn;