tests/qtest: Add RISC-V IOMMU bare-metal test

Add a qtest suite for the RISC-V IOMMU PCI device on the virt machine.
The test exercises bare, S-stage, G-stage, and nested translation paths
using iommu-testdev and the qos-riscv-iommu helpers.

The test validates:
- Device context (DC) configuration
- SV39 page table walks for S-stage translation
- SV39x4 page table walks for G-stage translation
- Nested translation combining both stages
- FCTL register constraints

This provides regression coverage for the RISC-V IOMMU implementation
without requiring a full guest OS boot.

Signed-off-by: Chao Liu <[email protected]>

Author: zevorn

MAINTAINERS

@@ -347,6 +347,7 @@ F: common-user/host/riscv*
 F: tests/functional/riscv32
 F: tests/functional/riscv64
 F: tests/tcg/riscv64/
+F: tests/qtest/iommu-riscv-test.c
 
 RISC-V XThead* extensions
 M: Christoph Muellner <[email protected]>

tests/qtest/iommu-riscv-test.c

@@ -0,0 +1,279 @@
+/*
+ * QTest testcase for RISC-V IOMMU with iommu-testdev
+ *
+ * This QTest file is used to test the RISC-V IOMMU with iommu-testdev so that
+ * we can test RISC-V IOMMU without any guest kernel or firmware.
+ *
+ * Copyright (c) 2026 Chao Liu <[email protected]>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "libqtest.h"
+#include "libqos/pci.h"
+#include "libqos/generic-pcihost.h"
+#include "hw/pci/pci_regs.h"
+#include "hw/misc/iommu-testdev.h"
+#include "hw/riscv/riscv-iommu-bits.h"
+#include "libqos/qos-riscv-iommu.h"
+#include "libqos/riscv-iommu.h"
+
+#define DMA_LEN           4
+
+/* RISC-V virt machine PCI configuration */
+#define RISCV_GPEX_PIO_BASE        0x3000000
+#define RISCV_BUS_PIO_LIMIT        0x10000
+#define RISCV_BUS_MMIO_ALLOC_PTR   0x40000000
+#define RISCV_BUS_MMIO_LIMIT       0x80000000
+#define RISCV_ECAM_ALLOC_PTR       0x30000000
+
+typedef struct RiscvIommuTestState {
+    QTestState *qts;
+    QGenericPCIBus gbus;
+    QPCIDevice *iommu_dev;
+    QPCIDevice *testdev;
+    QPCIBar testdev_bar;
+    uint64_t iommu_base;
+} RiscvIommuTestState;
+
+static void riscv_config_qpci_bus(QGenericPCIBus *qpci)
+{
+    qpci->gpex_pio_base = RISCV_GPEX_PIO_BASE;
+    qpci->bus.pio_limit = RISCV_BUS_PIO_LIMIT;
+    qpci->bus.mmio_alloc_ptr = RISCV_BUS_MMIO_ALLOC_PTR;
+    qpci->bus.mmio_limit = RISCV_BUS_MMIO_LIMIT;
+    qpci->ecam_alloc_ptr = RISCV_ECAM_ALLOC_PTR;
+}
+
+static uint64_t riscv_iommu_expected_gpa(uint64_t iova)
+{
+    return QRIOMMU_SPACE_OFFS + QRIOMMU_L2_PTE_VAL + (iova & 0xfff);
+}
+
+static void save_fn(QPCIDevice *dev, int devfn, void *data)
+{
+    QPCIDevice **pdev = (QPCIDevice **) data;
+    uint16_t vendor = qpci_config_readw(dev, 0);
+    uint16_t device = qpci_config_readw(dev, 2);
+
+    g_test_message("Found PCI device: vendor=0x%04x device=0x%04x devfn=0x%02x",
+                   vendor, device, devfn);
+
+    if (!*pdev) {
+        *pdev = dev;
+    }
+}
+
+static QPCIDevice *find_riscv_iommu_pci(QGenericPCIBus *gbus,
+                                        uint64_t *iommu_base)
+{
+    QPCIDevice *iommu_dev = NULL;
+    QPCIBar iommu_bar;
+
+    g_test_message("Searching for riscv-iommu-pci "
+                   "(vendor=0x%04x, device=0x%04x)",
+                   RISCV_IOMMU_PCI_VENDOR_ID, RISCV_IOMMU_PCI_DEVICE_ID);
+
+    qpci_device_foreach(&gbus->bus, RISCV_IOMMU_PCI_VENDOR_ID,
+                        RISCV_IOMMU_PCI_DEVICE_ID, save_fn, &iommu_dev);
+
+    if (!iommu_dev) {
+        g_test_message("riscv-iommu-pci device not found!");
+        return NULL;
+    }
+
+    g_test_message("Found riscv-iommu-pci at devfn=0x%02x", iommu_dev->devfn);
+
+    qpci_device_enable(iommu_dev);
+    iommu_bar = qpci_iomap(iommu_dev, 0, NULL);
+    g_assert_false(iommu_bar.is_io);
+
+    *iommu_base = iommu_bar.addr;
+    g_test_message("RISC-V IOMMU MMIO base address: 0x%" PRIx64, *iommu_base);
+
+    return iommu_dev;
+}
+
+static QPCIDevice *find_iommu_testdev(QGenericPCIBus *gbus, QPCIBar *bar)
+{
+    QPCIDevice *dev = NULL;
+
+    g_test_message("Searching for iommu-testdev (vendor=0x%04x, device=0x%04x)",
+                   IOMMU_TESTDEV_VENDOR_ID, IOMMU_TESTDEV_DEVICE_ID);
+
+    qpci_device_foreach(&gbus->bus, IOMMU_TESTDEV_VENDOR_ID,
+                        IOMMU_TESTDEV_DEVICE_ID, save_fn, &dev);
+    g_assert(dev);
+
+    qpci_device_enable(dev);
+    *bar = qpci_iomap(dev, 0, NULL);
+    g_assert_false(bar->is_io);
+
+    return dev;
+}
+
+static bool riscv_iommu_test_setup(RiscvIommuTestState *state)
+{
+    if (!qtest_has_machine("virt")) {
+        g_test_skip("virt machine not available");
+        return false;
+    }
+
+    state->qts = qtest_init("-machine virt,acpi=off "
+                            "-cpu max -smp 1 -m 512 -net none "
+                            "-device riscv-iommu-pci "
+                            "-device iommu-testdev");
+
+    qpci_init_generic(&state->gbus, state->qts, NULL, false);
+    riscv_config_qpci_bus(&state->gbus);
+
+    state->iommu_dev = find_riscv_iommu_pci(&state->gbus, &state->iommu_base);
+    g_assert(state->iommu_dev);
+
+    state->testdev = find_iommu_testdev(&state->gbus, &state->testdev_bar);
+    g_assert(state->testdev);
+
+    return true;
+}
+
+static void riscv_iommu_test_teardown(RiscvIommuTestState *state)
+{
+    qtest_quit(state->qts);
+}
+
+static uint64_t riscv_iommu_check(QTestState *qts, uint64_t iommu_base,
+                                  QRIOMMUTransMode mode)
+{
+    uint64_t cap;
+    uint64_t ddtp;
+    uint32_t cqcsr;
+    uint32_t fqcsr;
+    uint32_t pqcsr;
+    uint32_t fctl;
+    uint32_t fctl_mask;
+    uint32_t fctl_desired;
+    uint32_t igs;
+
+    cap = qtest_readq(qts, iommu_base + RISCV_IOMMU_REG_CAP);
+    g_assert_cmpuint((uint32_t)(cap & RISCV_IOMMU_CAP_VERSION), ==,
+                     RISCV_IOMMU_SPEC_DOT_VER);
+
+    fctl = qtest_readl(qts, iommu_base + RISCV_IOMMU_REG_FCTL);
+    igs = (cap & RISCV_IOMMU_CAP_IGS) >> 28;
+    g_assert_cmpuint(igs, <=, RISCV_IOMMU_CAP_IGS_BOTH);
+
+    fctl_mask = RISCV_IOMMU_FCTL_BE | RISCV_IOMMU_FCTL_WSI |
+                RISCV_IOMMU_FCTL_GXL;
+    fctl_desired = fctl & ~fctl_mask;
+    if (igs == RISCV_IOMMU_CAP_IGS_WSI) {
+        fctl_desired |= RISCV_IOMMU_FCTL_WSI;
+    }
+
+    if ((fctl & fctl_mask) != (fctl_desired & fctl_mask)) {
+        ddtp = qtest_readq(qts, iommu_base + RISCV_IOMMU_REG_DDTP);
+        cqcsr = qtest_readl(qts, iommu_base + RISCV_IOMMU_REG_CQCSR);
+        fqcsr = qtest_readl(qts, iommu_base + RISCV_IOMMU_REG_FQCSR);
+        pqcsr = qtest_readl(qts, iommu_base + RISCV_IOMMU_REG_PQCSR);
+
+        g_assert_cmpuint((uint32_t)(ddtp & RISCV_IOMMU_DDTP_MODE), ==,
+                         RISCV_IOMMU_DDTP_MODE_OFF);
+        g_assert_cmpuint(cqcsr & RISCV_IOMMU_CQCSR_CQON, ==, 0);
+        g_assert_cmpuint(fqcsr & RISCV_IOMMU_FQCSR_FQON, ==, 0);
+        g_assert_cmpuint(pqcsr & RISCV_IOMMU_PQCSR_PQON, ==, 0);
+
+        qtest_writel(qts, iommu_base + RISCV_IOMMU_REG_FCTL, fctl_desired);
+        fctl = qtest_readl(qts, iommu_base + RISCV_IOMMU_REG_FCTL);
+    }
+
+    g_assert_cmpuint(fctl & fctl_mask, ==, fctl_desired & fctl_mask);
+
+    if (mode == QRIOMMU_TM_S_STAGE_ONLY || mode == QRIOMMU_TM_NESTED) {
+        g_assert((cap & RISCV_IOMMU_CAP_SV39) != 0);
+    }
+    if (mode == QRIOMMU_TM_G_STAGE_ONLY || mode == QRIOMMU_TM_NESTED) {
+        g_assert((cap & RISCV_IOMMU_CAP_SV39X4) != 0);
+        g_assert_cmpuint(fctl & RISCV_IOMMU_FCTL_GXL, ==, 0);
+    }
+
+    return cap;
+}
+
+static void run_riscv_iommu_translation(const QRIOMMUTestConfig *cfg)
+{
+    RiscvIommuTestState state = { 0 };
+
+    if (!riscv_iommu_test_setup(&state)) {
+        return;
+    }
+
+    riscv_iommu_check(state.qts, state.iommu_base, cfg->trans_mode);
+
+    g_test_message("### RISC-V IOMMU translation mode=%d ###",
+                   cfg->trans_mode);
+    qriommu_run_translation_case(state.qts, state.testdev, state.testdev_bar,
+                                 state.iommu_base, cfg);
+    riscv_iommu_test_teardown(&state);
+}
+
+static void test_riscv_iommu_bare(void)
+{
+    QRIOMMUTestConfig cfg = {
+        .trans_mode = QRIOMMU_TM_BARE,
+        .dma_gpa = QRIOMMU_IOVA,
+        .dma_len = DMA_LEN,
+        .expected_result = 0,
+    };
+
+    run_riscv_iommu_translation(&cfg);
+}
+
+static void test_riscv_iommu_s_stage_only(void)
+{
+    QRIOMMUTestConfig cfg = {
+        .trans_mode = QRIOMMU_TM_S_STAGE_ONLY,
+        .dma_gpa = riscv_iommu_expected_gpa(QRIOMMU_IOVA),
+        .dma_len = DMA_LEN,
+        .expected_result = 0,
+    };
+
+    run_riscv_iommu_translation(&cfg);
+}
+
+static void test_riscv_iommu_g_stage_only(void)
+{
+    QRIOMMUTestConfig cfg = {
+        .trans_mode = QRIOMMU_TM_G_STAGE_ONLY,
+        .dma_gpa = riscv_iommu_expected_gpa(QRIOMMU_IOVA),
+        .dma_len = DMA_LEN,
+        .expected_result = 0,
+    };
+
+    run_riscv_iommu_translation(&cfg);
+}
+
+static void test_riscv_iommu_nested(void)
+{
+    QRIOMMUTestConfig cfg = {
+        .trans_mode = QRIOMMU_TM_NESTED,
+        .dma_gpa = riscv_iommu_expected_gpa(QRIOMMU_IOVA),
+        .dma_len = DMA_LEN,
+        .expected_result = 0,
+    };
+
+    run_riscv_iommu_translation(&cfg);
+}
+
+int main(int argc, char **argv)
+{
+    g_test_init(&argc, &argv, NULL);
+    qtest_add_func("/iommu-testdev/translation/bare",
+                   test_riscv_iommu_bare);
+    qtest_add_func("/iommu-testdev/translation/s-stage-only",
+                   test_riscv_iommu_s_stage_only);
+    qtest_add_func("/iommu-testdev/translation/g-stage-only",
+                   test_riscv_iommu_g_stage_only);
+    qtest_add_func("/iommu-testdev/translation/ns-nested",
+                   test_riscv_iommu_nested);
+    return g_test_run();
+}

tests/qtest/meson.build

@@ -286,7 +286,10 @@ qtests_riscv32 = \
   (config_all_devices.has_key('CONFIG_SIFIVE_E_AON') ? ['sifive-e-aon-watchdog-test'] : [])
 
 qtests_riscv64 = ['riscv-csr-test'] + \
-  (unpack_edk2_blobs ? ['bios-tables-test'] : [])
+  (unpack_edk2_blobs ? ['bios-tables-test'] : []) + \
+  (config_all_devices.has_key('CONFIG_IOMMU_TESTDEV') and
+   config_all_devices.has_key('CONFIG_RISCV_IOMMU') ?
+   ['iommu-riscv-test'] : [])
 
 qos_test_ss = ss.source_set()
 qos_test_ss.add(