[5/9] hw/arm/virt: GICv3 DT node with one or two redistributor regions

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(-)

On Wed, Jun 13, 2018 at 10:48:39AM +0200, Eric Auger wrote:
> 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 2885d18..5c02cc5 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -148,6 +148,8 @@ 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 },

No need for the ULL on the size. It messes up some alignment when the 2nd
ECAM region is added with patch 8/9.

>      /* Second PCIe window, 512GB wide at the 512GB boundary */
>      [VIRT_PCIE_MMIO_HIGH] =   { 0x8000000000ULL, 0x8000000000ULL },
>  };
> @@ -401,13 +403,30 @@ 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);
> +        }

You could handle a general number of redists by building an array and
calling qemu_fdt_setprop_sized_cells_from_array() directly. But, OTOH,
the memory map supports up to exactly two, so that's the current max
anyway.

> +
>          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;

Another place that would need to be patched if we ever add a third region.

> +}
> +
>  #endif /* QEMU_ARM_VIRT_H */
> -- 
> 2.5.5
> 
> 

Besides feeling like we should write code that supports > 1 region,
vs. exactly 1 or 2 and the ULL nit, looks good to me

Reviewed-by: Andrew Jones <drjones@redhat.com>