Re: [PATCH v5 05/13] hw/riscv: add riscv-iommu-pci reference device

[Alistair Francis]

On Tue, Jul 9, 2024 at 3:38 AM Daniel Henrique Barboza
<dbarboza@ventanamicro.com> wrote:
>
> From: Tomasz Jeznach <tjeznach@rivosinc.com>
>
> The RISC-V IOMMU can be modelled as a PCIe device following the
> guidelines of the RISC-V IOMMU spec, chapter 7.1, "Integrating an IOMMU
> as a PCIe device".
>
> Signed-off-by: Tomasz Jeznach <tjeznach@rivosinc.com>
> Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
> Reviewed-by: Frank Chang <frank.chang@sifive.com>

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

> ---
>  hw/riscv/meson.build       |   2 +-
>  hw/riscv/riscv-iommu-pci.c | 178 +++++++++++++++++++++++++++++++++++++
>  2 files changed, 179 insertions(+), 1 deletion(-)
>  create mode 100644 hw/riscv/riscv-iommu-pci.c
>
> diff --git a/hw/riscv/meson.build b/hw/riscv/meson.build
> index cbc99c6e8e..adbef8a9b2 100644
> --- a/hw/riscv/meson.build
> +++ b/hw/riscv/meson.build
> @@ -10,6 +10,6 @@ riscv_ss.add(when: 'CONFIG_SIFIVE_U', if_true: 
> files('sifive_u.c'))
>  riscv_ss.add(when: 'CONFIG_SPIKE', if_true: files('spike.c'))
>  riscv_ss.add(when: 'CONFIG_MICROCHIP_PFSOC', if_true: 
> files('microchip_pfsoc.c'))
>  riscv_ss.add(when: 'CONFIG_ACPI', if_true: files('virt-acpi-build.c'))
> -riscv_ss.add(when: 'CONFIG_RISCV_IOMMU', if_true: files('riscv-iommu.c'))
> +riscv_ss.add(when: 'CONFIG_RISCV_IOMMU', if_true: files('riscv-iommu.c', 
> 'riscv-iommu-pci.c'))
>
>  hw_arch += {'riscv': riscv_ss}
> diff --git a/hw/riscv/riscv-iommu-pci.c b/hw/riscv/riscv-iommu-pci.c
> new file mode 100644
> index 0000000000..7b82ce0645
> --- /dev/null
> +++ b/hw/riscv/riscv-iommu-pci.c
> @@ -0,0 +1,178 @@
> +/*
> + * QEMU emulation of an RISC-V IOMMU
> + *
> + * Copyright (C) 2022-2023 Rivos Inc.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License along
> + * with this program; if not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include "qemu/osdep.h"
> +#include "hw/pci/msi.h"
> +#include "hw/pci/msix.h"
> +#include "hw/pci/pci_bus.h"
> +#include "hw/qdev-properties.h"
> +#include "hw/riscv/riscv_hart.h"
> +#include "migration/vmstate.h"
> +#include "qapi/error.h"
> +#include "qemu/error-report.h"
> +#include "qemu/host-utils.h"
> +#include "qom/object.h"
> +
> +#include "cpu_bits.h"
> +#include "riscv-iommu.h"
> +#include "riscv-iommu-bits.h"
> +
> +/* RISC-V IOMMU PCI Device Emulation */
> +#define RISCV_PCI_CLASS_SYSTEM_IOMMU     0x0806
> +
> +typedef struct RISCVIOMMUStatePci {
> +    PCIDevice        pci;     /* Parent PCIe device state */
> +    uint16_t         vendor_id;
> +    uint16_t         device_id;
> +    uint8_t          revision;
> +    MemoryRegion     bar0;    /* PCI BAR (including MSI-x config) */
> +    RISCVIOMMUState  iommu;   /* common IOMMU state */
> +} RISCVIOMMUStatePci;
> +
> +/* interrupt delivery callback */
> +static void riscv_iommu_pci_notify(RISCVIOMMUState *iommu, unsigned vector)
> +{
> +    RISCVIOMMUStatePci *s = container_of(iommu, RISCVIOMMUStatePci, iommu);
> +
> +    if (msix_enabled(&(s->pci))) {
> +        msix_notify(&(s->pci), vector);
> +    }
> +}
> +
> +static void riscv_iommu_pci_realize(PCIDevice *dev, Error **errp)
> +{
> +    RISCVIOMMUStatePci *s = DO_UPCAST(RISCVIOMMUStatePci, pci, dev);
> +    RISCVIOMMUState *iommu = &s->iommu;
> +    uint8_t *pci_conf = dev->config;
> +    Error *err = NULL;
> +
> +    pci_set_word(pci_conf + PCI_VENDOR_ID, s->vendor_id);
> +    pci_set_word(pci_conf + PCI_SUBSYSTEM_VENDOR_ID, s->vendor_id);
> +    pci_set_word(pci_conf + PCI_DEVICE_ID, s->device_id);
> +    pci_set_word(pci_conf + PCI_SUBSYSTEM_ID, s->device_id);
> +    pci_set_byte(pci_conf + PCI_REVISION_ID, s->revision);
> +
> +    /* Set device id for trace / debug */
> +    DEVICE(iommu)->id = g_strdup_printf("%02x:%02x.%01x",
> +        pci_dev_bus_num(dev), PCI_SLOT(dev->devfn), PCI_FUNC(dev->devfn));
> +    qdev_realize(DEVICE(iommu), NULL, errp);
> +
> +    memory_region_init(&s->bar0, OBJECT(s), "riscv-iommu-bar0",
> +        QEMU_ALIGN_UP(memory_region_size(&iommu->regs_mr), 
> TARGET_PAGE_SIZE));
> +    memory_region_add_subregion(&s->bar0, 0, &iommu->regs_mr);
> +
> +    pcie_endpoint_cap_init(dev, 0);
> +
> +    pci_register_bar(dev, 0, PCI_BASE_ADDRESS_SPACE_MEMORY |
> +                     PCI_BASE_ADDRESS_MEM_TYPE_64, &s->bar0);
> +
> +    int ret = msix_init(dev, RISCV_IOMMU_INTR_COUNT,
> +                        &s->bar0, 0, RISCV_IOMMU_REG_MSI_CONFIG,
> +                        &s->bar0, 0, RISCV_IOMMU_REG_MSI_CONFIG + 256, 0, 
> &err);
> +
> +    if (ret == -ENOTSUP) {
> +        /*
> +         * MSI-x is not supported by the platform.
> +         * Driver should use timer/polling based notification handlers.
> +         */
> +        warn_report_err(err);
> +    } else if (ret < 0) {
> +        error_propagate(errp, err);
> +        return;
> +    } else {
> +        /* mark all allocated MSIx vectors as used. */
> +        msix_vector_use(dev, RISCV_IOMMU_INTR_CQ);
> +        msix_vector_use(dev, RISCV_IOMMU_INTR_FQ);
> +        msix_vector_use(dev, RISCV_IOMMU_INTR_PM);
> +        msix_vector_use(dev, RISCV_IOMMU_INTR_PQ);
> +        iommu->notify = riscv_iommu_pci_notify;
> +    }
> +
> +    PCIBus *bus = pci_device_root_bus(dev);
> +    if (!bus) {
> +        error_setg(errp, "can't find PCIe root port for %02x:%02x.%x",
> +            pci_bus_num(pci_get_bus(dev)), PCI_SLOT(dev->devfn),
> +            PCI_FUNC(dev->devfn));
> +        return;
> +    }
> +
> +    riscv_iommu_pci_setup_iommu(iommu, bus, errp);
> +}
> +
> +static void riscv_iommu_pci_exit(PCIDevice *pci_dev)
> +{
> +    pci_setup_iommu(pci_device_root_bus(pci_dev), NULL, NULL);
> +}
> +
> +static const VMStateDescription riscv_iommu_vmstate = {
> +    .name = "riscv-iommu",
> +    .unmigratable = 1
> +};
> +
> +static void riscv_iommu_pci_init(Object *obj)
> +{
> +    RISCVIOMMUStatePci *s = RISCV_IOMMU_PCI(obj);
> +    RISCVIOMMUState *iommu = &s->iommu;
> +
> +    object_initialize_child(obj, "iommu", iommu, TYPE_RISCV_IOMMU);
> +    qdev_alias_all_properties(DEVICE(iommu), obj);
> +}
> +
> +static Property riscv_iommu_pci_properties[] = {
> +    DEFINE_PROP_UINT16("vendor-id", RISCVIOMMUStatePci, vendor_id,
> +                       PCI_VENDOR_ID_REDHAT),
> +    DEFINE_PROP_UINT16("device-id", RISCVIOMMUStatePci, device_id,
> +                       PCI_DEVICE_ID_REDHAT_RISCV_IOMMU),
> +    DEFINE_PROP_UINT8("revision", RISCVIOMMUStatePci, revision, 0x01),
> +    DEFINE_PROP_END_OF_LIST(),
> +};
> +
> +static void riscv_iommu_pci_class_init(ObjectClass *klass, void *data)
> +{
> +    DeviceClass *dc = DEVICE_CLASS(klass);
> +    PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
> +
> +    k->realize = riscv_iommu_pci_realize;
> +    k->exit = riscv_iommu_pci_exit;
> +    k->class_id = RISCV_PCI_CLASS_SYSTEM_IOMMU;
> +    dc->desc = "RISCV-IOMMU DMA Remapping device";
> +    dc->vmsd = &riscv_iommu_vmstate;
> +    dc->hotpluggable = false;
> +    dc->user_creatable = true;
> +    set_bit(DEVICE_CATEGORY_MISC, dc->categories);
> +    device_class_set_props(dc, riscv_iommu_pci_properties);
> +}
> +
> +static const TypeInfo riscv_iommu_pci = {
> +    .name = TYPE_RISCV_IOMMU_PCI,
> +    .parent = TYPE_PCI_DEVICE,
> +    .class_init = riscv_iommu_pci_class_init,
> +    .instance_init = riscv_iommu_pci_init,
> +    .instance_size = sizeof(RISCVIOMMUStatePci),
> +    .interfaces = (InterfaceInfo[]) {
> +        { INTERFACE_PCIE_DEVICE },
> +        { },
> +    },
> +};
> +
> +static void riscv_iommu_register_pci_types(void)
> +{
> +    type_register_static(&riscv_iommu_pci);
> +}
> +
> +type_init(riscv_iommu_register_pci_types);
> --
> 2.45.2
>
>