[Qemu-devel] [RFC v3 5/8] 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 up to 512 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>

---

v2 -> v3:
- VIRT_GIC_REDIST2 is now 64MB large, ie. 512 redistributor capacity
- virt_gicv3_redist_region_count does not test kvm_irqchip_in_kernel
  anymore
---
 hw/arm/virt.c         | 29 ++++++++++++++++++++++++-----
 include/hw/arm/virt.h | 14 ++++++++++++++
 2 files changed, 38 insertions(+), 5 deletions(-)

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index ed79460..3018ec2 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -149,6 +149,8 @@ static const MemMapEntry a15memmap[] = {
     [VIRT_PCIE_PIO] =           { 0x3eff0000, 0x00010000 },
     [VIRT_PCIE_ECAM] =          { 0x3f000000, 0x01000000 },
     [VIRT_MEM] =                { 0x40000000, RAMLIMIT_BYTES },
+    /* Additional 64 MB redist region (can contain up to 512 redistributors) */
+    [VIRT_GIC_REDIST2] =        { 0x4000000000ULL, 0x4000000ULL },
     /* Second PCIe window, 512GB wide at the 512GB boundary */
     [VIRT_PCIE_MMIO_HIGH] =   { 0x8000000000ULL, 0x8000000000ULL },
 };
@@ -402,13 +404,30 @@ 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 4ac7ef6..308156f 100644
--- a/include/hw/arm/virt.h
+++ b/include/hw/arm/virt.h
@@ -35,6 +35,8 @@
 #include "qemu/notify.h"
 #include "hw/boards.h"
 #include "hw/arm/arm.h"
+#include "sysemu/kvm.h"
+#include "hw/intc/arm_gicv3_common.h"
 
 #define NUM_GICV2M_SPIS       64
 #define NUM_VIRTIO_TRANSPORTS 32
@@ -60,6 +62,7 @@ enum {
     VIRT_GIC_V2M,
     VIRT_GIC_ITS,
     VIRT_GIC_REDIST,
+    VIRT_GIC_REDIST2,
     VIRT_SMMU,
     VIRT_UART,
     VIRT_MMIO,
@@ -130,4 +133,15 @@ 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 redist0_capacity =
+                vms->memmap[VIRT_GIC_REDIST].size / GICV3_REDIST_SIZE;
+
+    assert(vms->gic_version == 3);
+
+    return vms->smp_cpus > redist0_capacity ? 2 : 1;
+}
+
 #endif /* QEMU_ARM_VIRT_H */
-- 
2.5.5