Re: [PATCH v2 06/15] hw/riscv/virt.c: support for RISC-V IOMMU PCIDevice hotplug

[Eric Cheng <eric.cheng.linux@gmail.com>]

On 3/8/2024 12:03 AM, Daniel Henrique Barboza wrote:
> From: Tomasz Jeznach <tjeznach@rivosinc.com>
> 
> Generate device tree entry for riscv-iommu PCI device, along with
> mapping all PCI device identifiers to the single IOMMU device instance.
> 
> Signed-off-by: Tomasz Jeznach <tjeznach@rivosinc.com>
> Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
> ---
>   hw/riscv/virt.c | 33 ++++++++++++++++++++++++++++++++-
>   1 file changed, 32 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/riscv/virt.c b/hw/riscv/virt.c
> index a094af97c3..67a8267747 100644
> --- a/hw/riscv/virt.c
> +++ b/hw/riscv/virt.c
> @@ -32,6 +32,7 @@
>   #include "hw/core/sysbus-fdt.h"
>   #include "target/riscv/pmu.h"
>   #include "hw/riscv/riscv_hart.h"
> +#include "hw/riscv/iommu.h"
>   #include "hw/riscv/virt.h"
>   #include "hw/riscv/boot.h"
>   #include "hw/riscv/numa.h"
> @@ -1004,6 +1005,30 @@ static void create_fdt_virtio_iommu(RISCVVirtState *s, uint16_t bdf)
>                              bdf + 1, iommu_phandle, bdf + 1, 0xffff - bdf);
>   }
>   
> +static void create_fdt_iommu(RISCVVirtState *s, uint16_t bdf)
> +{
> +    const char comp[] = "riscv,pci-iommu";
> +    void *fdt = MACHINE(s)->fdt;
> +    uint32_t iommu_phandle;
> +    g_autofree char *iommu_node = NULL;
> +    g_autofree char *pci_node = NULL;
> +
> +    pci_node = g_strdup_printf("/soc/pci@%lx",
> +                               (long) virt_memmap[VIRT_PCIE_ECAM].base);
> +    iommu_node = g_strdup_printf("%s/iommu@%x", pci_node, bdf);
> +    iommu_phandle = qemu_fdt_alloc_phandle(fdt);
> +    qemu_fdt_add_subnode(fdt, iommu_node);
> +
> +    qemu_fdt_setprop(fdt, iommu_node, "compatible", comp, sizeof(comp));
> +    qemu_fdt_setprop_cell(fdt, iommu_node, "#iommu-cells", 1);
> +    qemu_fdt_setprop_cell(fdt, iommu_node, "phandle", iommu_phandle);
> +    qemu_fdt_setprop_cells(fdt, iommu_node, "reg",
> +                           bdf << 8, 0, 0, 0, 0);
> +    qemu_fdt_setprop_cells(fdt, pci_node, "iommu-map",
> +                           0, iommu_phandle, 0, bdf,
> +                           bdf + 1, iommu_phandle, bdf + 1, 0xffff - bdf);
> +}

Is it really necessary to add this iommu-pci device in riscv virt machine, 
rather than other 'physical' machine type? virt machine already has its 
virtio-iommu.

> +
>   static void finalize_fdt(RISCVVirtState *s)
>   {
>       uint32_t phandle = 1, irq_mmio_phandle = 1, msi_pcie_phandle = 1;
> @@ -1712,9 +1737,11 @@ static HotplugHandler *virt_machine_get_hotplug_handler(MachineState *machine,
>       MachineClass *mc = MACHINE_GET_CLASS(machine);
>   
>       if (device_is_dynamic_sysbus(mc, dev) ||
> -        object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_IOMMU_PCI)) {
> +        object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_IOMMU_PCI) ||
> +        object_dynamic_cast(OBJECT(dev), TYPE_RISCV_IOMMU_PCI)) {
>           return HOTPLUG_HANDLER(machine);
>       }
> +
>       return NULL;
>   }
>   
> @@ -1735,6 +1762,10 @@ static void virt_machine_device_plug_cb(HotplugHandler *hotplug_dev,
>       if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_IOMMU_PCI)) {
>           create_fdt_virtio_iommu(s, pci_get_bdf(PCI_DEVICE(dev)));
>       }
> +
> +    if (object_dynamic_cast(OBJECT(dev), TYPE_RISCV_IOMMU_PCI)) {
> +        create_fdt_iommu(s, pci_get_bdf(PCI_DEVICE(dev)));
> +    }
>   }
>   
>   static void virt_machine_class_init(ObjectClass *oc, void *data)