[Qemu-devel] [PATCH v3 14/20] intc/arm_gic: Wire the vCPU interface

[Luc Michel <luc.michel@greensocs.com>]

Add the read/write functions to handle accesses to the vCPU interface.
Those accesses are forwarded to the real CPU interface, with the CPU id
being converted to the corresponding vCPU id (vCPU id = CPU id +
GIC_NCPU).

As for the CPU interface, we create a base region for the vCPU interface
that fetches the current vCPU id using the current_cpu global variable, and
one mirror region per vCPU which maps to that specific vCPU id. This is
required by the GIC architecture specification.

Signed-off-by: Luc Michel <luc.michel@greensocs.com>
---
 hw/intc/arm_gic.c | 71 ++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 70 insertions(+), 1 deletion(-)

diff --git a/hw/intc/arm_gic.c b/hw/intc/arm_gic.c
index 2b1fa280eb..9bbd544a5c 100644
--- a/hw/intc/arm_gic.c
+++ b/hw/intc/arm_gic.c
@@ -1488,6 +1488,46 @@ static MemTxResult gic_do_cpu_write(void *opaque, hwaddr addr,
     GICState *s = *backref;
     int id = (backref - s->backref);
     return gic_cpu_write(s, id, addr, value, attrs);
+
+}
+
+static MemTxResult gic_thisvcpu_read(void *opaque, hwaddr addr, uint64_t *data,
+                                    unsigned size, MemTxAttrs attrs)
+{
+    GICState *s = (GICState *)opaque;
+
+    return gic_cpu_read(s, gic_get_current_vcpu(s), addr, data, attrs);
+}
+
+static MemTxResult gic_thisvcpu_write(void *opaque, hwaddr addr,
+                                     uint64_t value, unsigned size,
+                                     MemTxAttrs attrs)
+{
+    GICState *s = (GICState *)opaque;
+
+    return gic_cpu_write(s, gic_get_current_vcpu(s), addr, value, attrs);
+}
+
+static MemTxResult gic_do_vcpu_read(void *opaque, hwaddr addr, uint64_t *data,
+                                    unsigned size, MemTxAttrs attrs)
+{
+    GICState **backref = (GICState **)opaque;
+    GICState *s = *backref;
+    int id = (backref - s->backref);
+
+    return gic_cpu_read(s, id + GIC_NCPU, addr, data, attrs);
+}
+
+static MemTxResult gic_do_vcpu_write(void *opaque, hwaddr addr,
+                                     uint64_t value, unsigned size,
+                                     MemTxAttrs attrs)
+{
+    GICState **backref = (GICState **)opaque;
+    GICState *s = *backref;
+    int id = (backref - s->backref);
+
+    return gic_cpu_write(s, id + GIC_NCPU, addr, value, attrs);
+
 }
 
 static const MemoryRegionOps gic_ops[2] = {
@@ -1509,6 +1549,25 @@ static const MemoryRegionOps gic_cpu_ops = {
     .endianness = DEVICE_NATIVE_ENDIAN,
 };
 
+static const MemoryRegionOps gic_virt_ops[2] = {
+    {
+        .read_with_attrs = NULL,
+        .write_with_attrs = NULL,
+        .endianness = DEVICE_NATIVE_ENDIAN,
+    },
+    {
+        .read_with_attrs = gic_thisvcpu_read,
+        .write_with_attrs = gic_thisvcpu_write,
+        .endianness = DEVICE_NATIVE_ENDIAN,
+    }
+};
+
+static const MemoryRegionOps gic_vcpu_ops = {
+    .read_with_attrs = gic_do_vcpu_read,
+    .write_with_attrs = gic_do_vcpu_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+};
+
 static void arm_gic_realize(DeviceState *dev, Error **errp)
 {
     /* Device instance realize function for the GIC sysbus device */
@@ -1531,7 +1590,7 @@ static void arm_gic_realize(DeviceState *dev, Error **errp)
     }
 
     /* This creates distributor and main CPU interface (s->cpuiomem[0]) */
-    gic_init_irqs_and_mmio(s, gic_set_irq, gic_ops, NULL);
+    gic_init_irqs_and_mmio(s, gic_set_irq, gic_ops, gic_virt_ops);
 
     /* Extra core-specific regions for the CPU interfaces. This is
      * necessary for "franken-GIC" implementations, for example on
@@ -1547,6 +1606,16 @@ static void arm_gic_realize(DeviceState *dev, Error **errp)
                               &s->backref[i], "gic_cpu", 0x100);
         sysbus_init_mmio(sbd, &s->cpuiomem[i+1]);
     }
+
+    if (s->virt_extn) {
+        for (i = 0; i < s->num_cpu; i++) {
+            memory_region_init_io(&s->vcpuiomem[i + 1], OBJECT(s),
+                                  &gic_vcpu_ops, &s->backref[i],
+                                  "gic_vcpu", 0x2000);
+            sysbus_init_mmio(sbd, &s->vcpuiomem[i + 1]);
+        }
+    }
+
 }
 
 static void arm_gic_class_init(ObjectClass *klass, void *data)
-- 
2.17.1