[Qemu-arm] [RFC v2 5/7] hw/arm/virt: GICv3 DT node with one or two redistributor regions

[Eric Auger <eric.auger@redhat.com>]

This patch allows the creation of a GICv3 node with 1 or 2
redistributor regions depending on the number of smu_cpus.
The second redistributor region is located just after the
existing RAM region, at 256GB and contains up to (512 - 123) vcpus.

Please refer to kernel documentation for further node details:
Documentation/devicetree/bindings/interrupt-controller/arm,gic-v3.txt

Signed-off-by: Eric Auger <eric.auger@redhat.com>
---
 hw/arm/virt.c         | 29 ++++++++++++++++++++++++-----
 include/hw/arm/virt.h | 12 ++++++++++++
 2 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index c9d842d..f35962a 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -151,6 +151,8 @@ static const MemMapEntry a15memmap[] = {
     [VIRT_PCIE_PIO] =           { 0x3eff0000, 0x00010000 },
     [VIRT_PCIE_ECAM] =          { 0x3f000000, 0x01000000 },
     [VIRT_MEM] =                { 0x40000000, RAMLIMIT_BYTES },
+    /* Allows 512 - 123 additional vcpus (each 2x64kB) */
+    [VIRT_GIC_REDIST2] =        { 0x4000000000ULL, 0x30A0000LL },
     /* Second PCIe window, 512GB wide at the 512GB boundary */
     [VIRT_PCIE_MMIO_HIGH] =   { 0x8000000000ULL, 0x8000000000ULL },
 };
@@ -404,13 +406,30 @@ static void fdt_add_gic_node(VirtMachineState *vms)
     qemu_fdt_setprop_cell(vms->fdt, "/intc", "#size-cells", 0x2);
     qemu_fdt_setprop(vms->fdt, "/intc", "ranges", NULL, 0);
     if (vms->gic_version == 3) {
+        int nb_redist_regions = virt_gicv3_redist_region_count(vms);
+
         qemu_fdt_setprop_string(vms->fdt, "/intc", "compatible",
                                 "arm,gic-v3");
-        qemu_fdt_setprop_sized_cells(vms->fdt, "/intc", "reg",
-                                     2, vms->memmap[VIRT_GIC_DIST].base,
-                                     2, vms->memmap[VIRT_GIC_DIST].size,
-                                     2, vms->memmap[VIRT_GIC_REDIST].base,
-                                     2, vms->memmap[VIRT_GIC_REDIST].size);
+
+        qemu_fdt_setprop_cell(vms->fdt, "/intc",
+                              "#redistributor-regions", nb_redist_regions);
+
+        if (nb_redist_regions == 1) {
+            qemu_fdt_setprop_sized_cells(vms->fdt, "/intc", "reg",
+                                         2, vms->memmap[VIRT_GIC_DIST].base,
+                                         2, vms->memmap[VIRT_GIC_DIST].size,
+                                         2, vms->memmap[VIRT_GIC_REDIST].base,
+                                         2, vms->memmap[VIRT_GIC_REDIST].size);
+        } else {
+            qemu_fdt_setprop_sized_cells(vms->fdt, "/intc", "reg",
+                                         2, vms->memmap[VIRT_GIC_DIST].base,
+                                         2, vms->memmap[VIRT_GIC_DIST].size,
+                                         2, vms->memmap[VIRT_GIC_REDIST].base,
+                                         2, vms->memmap[VIRT_GIC_REDIST].size,
+                                         2, vms->memmap[VIRT_GIC_REDIST2].base,
+                                         2, vms->memmap[VIRT_GIC_REDIST2].size);
+        }
+
         if (vms->virt) {
             qemu_fdt_setprop_cells(vms->fdt, "/intc", "interrupts",
                                    GIC_FDT_IRQ_TYPE_PPI, ARCH_GICV3_MAINT_IRQ,
diff --git a/include/hw/arm/virt.h b/include/hw/arm/virt.h
index 886372c..ba52716 100644
--- a/include/hw/arm/virt.h
+++ b/include/hw/arm/virt.h
@@ -35,6 +35,7 @@
 #include "qemu/notify.h"
 #include "hw/boards.h"
 #include "hw/arm/arm.h"
+#include "sysemu/kvm.h"
 
 #define NUM_GICV2M_SPIS       64
 #define NUM_VIRTIO_TRANSPORTS 32
@@ -60,6 +61,7 @@ enum {
     VIRT_GIC_V2M,
     VIRT_GIC_ITS,
     VIRT_GIC_REDIST,
+    VIRT_GIC_REDIST2,
     VIRT_SMMU,
     VIRT_UART,
     VIRT_MMIO,
@@ -129,4 +131,14 @@ typedef struct {
 
 void virt_acpi_setup(VirtMachineState *vms);
 
+/* Return the number of used redistributor regions  */
+static inline int virt_gicv3_redist_region_count(VirtMachineState *vms)
+{
+    uint32_t rdist1_count = vms->memmap[VIRT_GIC_REDIST].size / 0x20000;
+
+    assert(vms->gic_version == 3);
+
+    return kvm_irqchip_in_kernel() && vms->smp_cpus > rdist1_count ? 2 : 1;
+}
+
 #endif /* QEMU_ARM_VIRT_H */
-- 
2.5.5