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>
---
hw/riscv/meson.build | 2 +-
hw/riscv/riscv-iommu-pci.c | 202 +++++++++++++++++++++++++++++++++++++
2 files changed, 203 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..a42242532d
--- /dev/null
+++ b/hw/riscv/riscv-iommu-pci.c
@@ -0,0 +1,202 @@
+/*
+ * 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 and conditions of the GNU General Public License,
+ * version 2 or later, as published by the Free Software Foundation.
+ *
+ * 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
+
+/*
+ * 4 MSIx vectors for ICVEC, one for MRIF. The spec mentions in
+ * the "Placement and data flow" section that:
+ *
+ * "The interfaces related to recording an incoming MSI in a memory-resident
+ * interrupt file (MRIF) are implementation-specific. The partitioning of
+ * responsibility between the IOMMU and the IO bridge for recording the
+ * incoming MSI in an MRIF and generating the associated notice MSI are
+ * implementation-specific."
+ *
+ * We're making a design decision to create the MSIx for MRIF in the
+ * IOMMU MSIx emulation.
+ */
+#define RISCV_IOMMU_PCI_MSIX_VECTORS 5
+
+/*
+ * 4 vectors that can be used by civ, fiv, pmiv and piv. Number of
+ * vectors is represented by 2^N, where N = number of writable bits
+ * in each cause. For 4 vectors we'll write 0b11 (3) in each reg.
+ */
+#define RISCV_IOMMU_PCI_ICVEC_VECTORS 0x3333
+
+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_PCI_MSIX_VECTORS,
+ &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 ICVEC MSIx vectors as used */
+ for (int i = 0; i < RISCV_IOMMU_PCI_MSIX_VECTORS; i++) {
+ msix_vector_use(dev, i);
+ }
+
+ 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);
+
+ iommu->icvec_avail_vectors = RISCV_IOMMU_PCI_ICVEC_VECTORS;
+}
+
+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