[v4,14/20] intc/arm_gic: Wire the vCPU interface

Commit Message

Luc Michel July 14, 2018, 5:15 p.m. UTC

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 <[e-mail]>
---
 hw/intc/arm_gic.c | 37 +++++++++++++++++++++++++++++++++++--
 1 file changed, 35 insertions(+), 2 deletions(-)

Comments

Peter Maydell July 17, 2018, 2:26 p.m. UTC | #1

On 14 July 2018 at 18:15, Luc Michel <[e-mail]> wrote:
> 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.

Is it? The spec says the GICH registers need to be accessible
like this, but not the vCPU (GICV) registers...

thanks
-- PMM

Luc Michel July 18, 2018, 1:24 p.m. UTC | #2

On 07/17/2018 04:26 PM, Peter Maydell wrote:
> On 14 July 2018 at 18:15, Luc Michel <[e-mail]> wrote:
>> 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.
> 
> Is it? The spec says the GICH registers need to be accessible
> like this, but not the vCPU (GICV) registers...
Sorry, I changed that in the patch but forgot to update the commit
message. I'll fix that.

Luc

> 
> thanks
> -- PMM
>

Patch

diff --git a/hw/intc/arm_gic.c b/hw/intc/arm_gic.c
index 28ecf0c1fc..be44015c39 100644
--- a/hw/intc/arm_gic.c
+++ b/hw/intc/arm_gic.c
@@ -1514,6 +1514,23 @@  static MemTxResult gic_do_cpu_write(void *opaque, hwaddr addr,
     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 const MemoryRegionOps gic_ops[2] = {
     {
         .read_with_attrs = gic_dist_read,
@@ -1533,6 +1550,19 @@  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 void arm_gic_realize(DeviceState *dev, Error **errp)
 {
     /* Device instance realize function for the GIC sysbus device */
@@ -1554,8 +1584,11 @@  static void arm_gic_realize(DeviceState *dev, Error **errp)
         return;
     }
 
-    /* This creates distributor and main CPU interface (s->cpuiomem[0]) */
-    gic_init_irqs_and_mmio(s, gic_set_irq, gic_ops, NULL);
+    /* This creates distributor, main CPU interface (s->cpuiomem[0]) and if
+     * enabled, virtualization extensions related interfaces (main virtual
+     * interface (s->vifaceiomem[0]) and virtual CPU interface).
+     */
+    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