[Qemu-devel] [PULL 27/27] arm/virt: Add full-sized CPU affinity handling

[Peter Maydell <peter.maydell@linaro.org>]

From: Pavel Fedin <p.fedin@samsung.com>

At least with KVM, currently there's no reason why QEMU would not be
capable of handling Aff3 != 0. This commit fixes up FDT creation in such
a case.

Signed-off-by: Pavel Fedin <p.fedin@samsung.com>
Message-id: eef5a86e6d9a313780dbc23b35fcb65df42a3e9e.1441366248.git.p.fedin@samsung.com
[PMM: folded two overlong lines]
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 hw/arm/virt.c | 34 ++++++++++++++++++++++++++++++++--
 1 file changed, 32 insertions(+), 2 deletions(-)

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 60736c2..91e45e0 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -288,9 +288,32 @@ static void fdt_add_timer_nodes(const VirtBoardInfo *vbi)
 static void fdt_add_cpu_nodes(const VirtBoardInfo *vbi)
 {
     int cpu;
+    int addr_cells = 1;
+
+    /*
+     * From Documentation/devicetree/bindings/arm/cpus.txt
+     *  On ARM v8 64-bit systems value should be set to 2,
+     *  that corresponds to the MPIDR_EL1 register size.
+     *  If MPIDR_EL1[63:32] value is equal to 0 on all CPUs
+     *  in the system, #address-cells can be set to 1, since
+     *  MPIDR_EL1[63:32] bits are not used for CPUs
+     *  identification.
+     *
+     *  Here we actually don't know whether our system is 32- or 64-bit one.
+     *  The simplest way to go is to examine affinity IDs of all our CPUs. If
+     *  at least one of them has Aff3 populated, we set #address-cells to 2.
+     */
+    for (cpu = 0; cpu < vbi->smp_cpus; cpu++) {
+        ARMCPU *armcpu = ARM_CPU(qemu_get_cpu(cpu));
+
+        if (armcpu->mp_affinity & ARM_AFF3_MASK) {
+            addr_cells = 2;
+            break;
+        }
+    }
 
     qemu_fdt_add_subnode(vbi->fdt, "/cpus");
-    qemu_fdt_setprop_cell(vbi->fdt, "/cpus", "#address-cells", 0x1);
+    qemu_fdt_setprop_cell(vbi->fdt, "/cpus", "#address-cells", addr_cells);
     qemu_fdt_setprop_cell(vbi->fdt, "/cpus", "#size-cells", 0x0);
 
     for (cpu = vbi->smp_cpus - 1; cpu >= 0; cpu--) {
@@ -307,7 +330,14 @@ static void fdt_add_cpu_nodes(const VirtBoardInfo *vbi)
                                         "enable-method", "psci");
         }
 
-        qemu_fdt_setprop_cell(vbi->fdt, nodename, "reg", armcpu->mp_affinity);
+        if (addr_cells == 2) {
+            qemu_fdt_setprop_u64(vbi->fdt, nodename, "reg",
+                                 armcpu->mp_affinity);
+        } else {
+            qemu_fdt_setprop_cell(vbi->fdt, nodename, "reg",
+                                  armcpu->mp_affinity);
+        }
+
         g_free(nodename);
     }
 }
-- 
1.9.1