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

[Daniel Henrique Barboza]

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>
---
 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