hw/acpi: Add VIOT table

Add a function that generates a Virtual I/O Translation table (VIOT),
describing the topology of paravirtual IOMMUs. The table is created if a
virtio-iommu device is present. It contains a virtio-iommu node and PCI
Range nodes for endpoints managed by the IOMMU. By default, a single
node describes all PCI devices. When passing the
"default_bus_bypass_iommu" machine option and "bypass_iommu" PXB option,
only buses that do not bypass the IOMMU are described by PCI Range
nodes.

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Tested-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Message-Id: <20211026182024.2642038-2-jean-philippe@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 114 insertions, 0 deletions

diff --git a/hw/acpi/viot.c b/hw/acpi/viot.c
new file mode 100644
index 0000000000..c1af75206e
--- /dev/null
+++ b/hw/acpi/viot.c
@@ -0,0 +1,114 @@
+/*
+ * ACPI Virtual I/O Translation table implementation
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+#include "qemu/osdep.h"
+#include "hw/acpi/acpi.h"
+#include "hw/acpi/aml-build.h"
+#include "hw/acpi/viot.h"
+#include "hw/pci/pci.h"
+#include "hw/pci/pci_host.h"
+
+struct viot_pci_ranges {
+    GArray *blob;
+    size_t count;
+    uint16_t output_node;
+};
+
+/* Build PCI range for a given PCI host bridge */
+static int build_pci_range_node(Object *obj, void *opaque)
+{
+    struct viot_pci_ranges *pci_ranges = opaque;
+    GArray *blob = pci_ranges->blob;
+
+    if (object_dynamic_cast(obj, TYPE_PCI_HOST_BRIDGE)) {
+        PCIBus *bus = PCI_HOST_BRIDGE(obj)->bus;
+
+        if (bus && !pci_bus_bypass_iommu(bus)) {
+            int min_bus, max_bus;
+
+            pci_bus_range(bus, &min_bus, &max_bus);
+
+            /* Type */
+            build_append_int_noprefix(blob, 1 /* PCI range */, 1);
+            /* Reserved */
+            build_append_int_noprefix(blob, 0, 1);
+            /* Length */
+            build_append_int_noprefix(blob, 24, 2);
+            /* Endpoint start */
+            build_append_int_noprefix(blob, PCI_BUILD_BDF(min_bus, 0), 4);
+            /* PCI Segment start */
+            build_append_int_noprefix(blob, 0, 2);
+            /* PCI Segment end */
+            build_append_int_noprefix(blob, 0, 2);
+            /* PCI BDF start */
+            build_append_int_noprefix(blob, PCI_BUILD_BDF(min_bus, 0), 2);
+            /* PCI BDF end */
+            build_append_int_noprefix(blob, PCI_BUILD_BDF(max_bus, 0xff), 2);
+            /* Output node */
+            build_append_int_noprefix(blob, pci_ranges->output_node, 2);
+            /* Reserved */
+            build_append_int_noprefix(blob, 0, 6);
+
+            pci_ranges->count++;
+        }
+    }
+
+    return 0;
+}
+
+/*
+ * Generate a VIOT table with one PCI-based virtio-iommu that manages PCI
+ * endpoints.
+ *
+ * Defined in the ACPI Specification (Version TBD)
+ */
+void build_viot(MachineState *ms, GArray *table_data, BIOSLinker *linker,
+                uint16_t virtio_iommu_bdf, const char *oem_id,
+                const char *oem_table_id)
+{
+    /* The virtio-iommu node follows the 48-bytes header */
+    int viommu_off = 48;
+    AcpiTable table = { .sig = "VIOT", .rev = 0,
+                        .oem_id = oem_id, .oem_table_id = oem_table_id };
+    struct viot_pci_ranges pci_ranges = {
+        .output_node = viommu_off,
+        .blob = g_array_new(false, true /* clear */, 1),
+    };
+
+    /* Build the list of PCI ranges that this viommu manages */
+    object_child_foreach_recursive(OBJECT(ms), build_pci_range_node,
+                                   &pci_ranges);
+
+    /* ACPI table header */
+    acpi_table_begin(&table, table_data);
+    /* Node count */
+    build_append_int_noprefix(table_data, pci_ranges.count + 1, 2);
+    /* Node offset */
+    build_append_int_noprefix(table_data, viommu_off, 2);
+    /* Reserved */
+    build_append_int_noprefix(table_data, 0, 8);
+
+    /* Virtio-iommu node */
+    /* Type */
+    build_append_int_noprefix(table_data, 3 /* virtio-pci IOMMU */, 1);
+    /* Reserved */
+    build_append_int_noprefix(table_data, 0, 1);
+    /* Length */
+    build_append_int_noprefix(table_data, 16, 2);
+    /* PCI Segment */
+    build_append_int_noprefix(table_data, 0, 2);
+    /* PCI BDF number */
+    build_append_int_noprefix(table_data, virtio_iommu_bdf, 2);
+    /* Reserved */
+    build_append_int_noprefix(table_data, 0, 8);
+
+    /* PCI ranges found above */
+    g_array_append_vals(table_data, pci_ranges.blob->data,
+                        pci_ranges.blob->len);
+    g_array_free(pci_ranges.blob, true);
+
+    acpi_table_end(linker, &table);
+}
+