381 lines
9.0 KiB
C
381 lines
9.0 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Virtual I/O topology
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*
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* The Virtual I/O Translation Table (VIOT) describes the topology of
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* para-virtual IOMMUs and the endpoints they manage. The OS uses it to
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* initialize devices in the right order, preventing endpoints from issuing DMA
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* before their IOMMU is ready.
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*
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* When binding a driver to a device, before calling the device driver's probe()
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* method, the driver infrastructure calls dma_configure(). At that point the
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* VIOT driver looks for an IOMMU associated to the device in the VIOT table.
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* If an IOMMU exists and has been initialized, the VIOT driver initializes the
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* device's IOMMU fwspec, allowing the DMA infrastructure to invoke the IOMMU
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* ops when the device driver configures DMA mappings. If an IOMMU exists and
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* hasn't yet been initialized, VIOT returns -EPROBE_DEFER to postpone probing
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* the device until the IOMMU is available.
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*/
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#define pr_fmt(fmt) "ACPI: VIOT: " fmt
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#include <linux/acpi_viot.h>
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#include <linux/fwnode.h>
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#include <linux/iommu.h>
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#include <linux/list.h>
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#include <linux/pci.h>
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#include <linux/platform_device.h>
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struct viot_iommu {
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/* Node offset within the table */
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unsigned int offset;
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struct fwnode_handle *fwnode;
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struct list_head list;
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};
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struct viot_endpoint {
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union {
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/* PCI range */
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struct {
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u16 segment_start;
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u16 segment_end;
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u16 bdf_start;
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u16 bdf_end;
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};
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/* MMIO */
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u64 address;
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};
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u32 endpoint_id;
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struct viot_iommu *viommu;
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struct list_head list;
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};
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static struct acpi_table_viot *viot;
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static LIST_HEAD(viot_iommus);
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static LIST_HEAD(viot_pci_ranges);
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static LIST_HEAD(viot_mmio_endpoints);
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static int __init viot_check_bounds(const struct acpi_viot_header *hdr)
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{
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struct acpi_viot_header *start, *end, *hdr_end;
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start = ACPI_ADD_PTR(struct acpi_viot_header, viot,
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max_t(size_t, sizeof(*viot), viot->node_offset));
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end = ACPI_ADD_PTR(struct acpi_viot_header, viot, viot->header.length);
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hdr_end = ACPI_ADD_PTR(struct acpi_viot_header, hdr, sizeof(*hdr));
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if (hdr < start || hdr_end > end) {
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pr_err(FW_BUG "Node pointer overflows\n");
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return -EOVERFLOW;
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}
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if (hdr->length < sizeof(*hdr)) {
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pr_err(FW_BUG "Empty node\n");
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return -EINVAL;
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}
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return 0;
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}
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static int __init viot_get_pci_iommu_fwnode(struct viot_iommu *viommu,
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u16 segment, u16 bdf)
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{
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struct pci_dev *pdev;
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struct fwnode_handle *fwnode;
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pdev = pci_get_domain_bus_and_slot(segment, PCI_BUS_NUM(bdf),
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bdf & 0xff);
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if (!pdev) {
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pr_err("Could not find PCI IOMMU\n");
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return -ENODEV;
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}
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fwnode = dev_fwnode(&pdev->dev);
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if (!fwnode) {
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/*
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* PCI devices aren't necessarily described by ACPI. Create a
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* fwnode so the IOMMU subsystem can identify this device.
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*/
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fwnode = acpi_alloc_fwnode_static();
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if (!fwnode) {
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pci_dev_put(pdev);
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return -ENOMEM;
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}
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set_primary_fwnode(&pdev->dev, fwnode);
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}
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viommu->fwnode = dev_fwnode(&pdev->dev);
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pci_dev_put(pdev);
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return 0;
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}
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static int __init viot_get_mmio_iommu_fwnode(struct viot_iommu *viommu,
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u64 address)
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{
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struct acpi_device *adev;
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struct resource res = {
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.start = address,
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.end = address,
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.flags = IORESOURCE_MEM,
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};
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adev = acpi_resource_consumer(&res);
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if (!adev) {
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pr_err("Could not find MMIO IOMMU\n");
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return -EINVAL;
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}
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viommu->fwnode = &adev->fwnode;
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return 0;
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}
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static struct viot_iommu * __init viot_get_iommu(unsigned int offset)
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{
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int ret;
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struct viot_iommu *viommu;
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struct acpi_viot_header *hdr = ACPI_ADD_PTR(struct acpi_viot_header,
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viot, offset);
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union {
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struct acpi_viot_virtio_iommu_pci pci;
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struct acpi_viot_virtio_iommu_mmio mmio;
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} *node = (void *)hdr;
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list_for_each_entry(viommu, &viot_iommus, list)
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if (viommu->offset == offset)
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return viommu;
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if (viot_check_bounds(hdr))
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return NULL;
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viommu = kzalloc(sizeof(*viommu), GFP_KERNEL);
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if (!viommu)
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return NULL;
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viommu->offset = offset;
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switch (hdr->type) {
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case ACPI_VIOT_NODE_VIRTIO_IOMMU_PCI:
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if (hdr->length < sizeof(node->pci))
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goto err_free;
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ret = viot_get_pci_iommu_fwnode(viommu, node->pci.segment,
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node->pci.bdf);
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break;
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case ACPI_VIOT_NODE_VIRTIO_IOMMU_MMIO:
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if (hdr->length < sizeof(node->mmio))
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goto err_free;
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ret = viot_get_mmio_iommu_fwnode(viommu,
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node->mmio.base_address);
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break;
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default:
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ret = -EINVAL;
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}
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if (ret)
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goto err_free;
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list_add(&viommu->list, &viot_iommus);
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return viommu;
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err_free:
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kfree(viommu);
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return NULL;
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}
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static int __init viot_parse_node(const struct acpi_viot_header *hdr)
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{
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int ret = -EINVAL;
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struct list_head *list;
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struct viot_endpoint *ep;
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union {
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struct acpi_viot_mmio mmio;
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struct acpi_viot_pci_range pci;
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} *node = (void *)hdr;
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if (viot_check_bounds(hdr))
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return -EINVAL;
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if (hdr->type == ACPI_VIOT_NODE_VIRTIO_IOMMU_PCI ||
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hdr->type == ACPI_VIOT_NODE_VIRTIO_IOMMU_MMIO)
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return 0;
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ep = kzalloc(sizeof(*ep), GFP_KERNEL);
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if (!ep)
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return -ENOMEM;
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switch (hdr->type) {
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case ACPI_VIOT_NODE_PCI_RANGE:
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if (hdr->length < sizeof(node->pci)) {
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pr_err(FW_BUG "Invalid PCI node size\n");
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goto err_free;
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}
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ep->segment_start = node->pci.segment_start;
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ep->segment_end = node->pci.segment_end;
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ep->bdf_start = node->pci.bdf_start;
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ep->bdf_end = node->pci.bdf_end;
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ep->endpoint_id = node->pci.endpoint_start;
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ep->viommu = viot_get_iommu(node->pci.output_node);
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list = &viot_pci_ranges;
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break;
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case ACPI_VIOT_NODE_MMIO:
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if (hdr->length < sizeof(node->mmio)) {
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pr_err(FW_BUG "Invalid MMIO node size\n");
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goto err_free;
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}
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ep->address = node->mmio.base_address;
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ep->endpoint_id = node->mmio.endpoint;
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ep->viommu = viot_get_iommu(node->mmio.output_node);
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list = &viot_mmio_endpoints;
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break;
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default:
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pr_warn("Unsupported node %x\n", hdr->type);
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ret = 0;
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goto err_free;
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}
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if (!ep->viommu) {
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pr_warn("No IOMMU node found\n");
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/*
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* A future version of the table may use the node for other
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* purposes. Keep parsing.
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*/
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ret = 0;
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goto err_free;
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}
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list_add(&ep->list, list);
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return 0;
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err_free:
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kfree(ep);
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return ret;
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}
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/**
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* acpi_viot_early_init - Test the presence of VIOT and enable ACS
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*
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* If the VIOT does exist, ACS must be enabled. This cannot be
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* done in acpi_viot_init() which is called after the bus scan
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*/
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void __init acpi_viot_early_init(void)
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{
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#ifdef CONFIG_PCI
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acpi_status status;
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struct acpi_table_header *hdr;
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status = acpi_get_table(ACPI_SIG_VIOT, 0, &hdr);
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if (ACPI_FAILURE(status))
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return;
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pci_request_acs();
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acpi_put_table(hdr);
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#endif
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}
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/**
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* acpi_viot_init - Parse the VIOT table
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*
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* Parse the VIOT table, prepare the list of endpoints to be used during DMA
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* setup of devices.
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*/
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void __init acpi_viot_init(void)
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{
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int i;
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acpi_status status;
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struct acpi_table_header *hdr;
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struct acpi_viot_header *node;
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status = acpi_get_table(ACPI_SIG_VIOT, 0, &hdr);
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if (ACPI_FAILURE(status)) {
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if (status != AE_NOT_FOUND) {
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const char *msg = acpi_format_exception(status);
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pr_err("Failed to get table, %s\n", msg);
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}
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return;
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}
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viot = (void *)hdr;
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node = ACPI_ADD_PTR(struct acpi_viot_header, viot, viot->node_offset);
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for (i = 0; i < viot->node_count; i++) {
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if (viot_parse_node(node))
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return;
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node = ACPI_ADD_PTR(struct acpi_viot_header, node,
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node->length);
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}
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acpi_put_table(hdr);
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}
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static int viot_dev_iommu_init(struct device *dev, struct viot_iommu *viommu,
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u32 epid)
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{
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const struct iommu_ops *ops;
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if (!viommu)
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return -ENODEV;
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/* We're not translating ourself */
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if (device_match_fwnode(dev, viommu->fwnode))
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return -EINVAL;
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ops = iommu_ops_from_fwnode(viommu->fwnode);
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if (!ops)
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return IS_ENABLED(CONFIG_VIRTIO_IOMMU) ?
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-EPROBE_DEFER : -ENODEV;
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return acpi_iommu_fwspec_init(dev, epid, viommu->fwnode, ops);
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}
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static int viot_pci_dev_iommu_init(struct pci_dev *pdev, u16 dev_id, void *data)
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{
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u32 epid;
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struct viot_endpoint *ep;
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struct device *aliased_dev = data;
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u32 domain_nr = pci_domain_nr(pdev->bus);
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list_for_each_entry(ep, &viot_pci_ranges, list) {
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if (domain_nr >= ep->segment_start &&
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domain_nr <= ep->segment_end &&
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dev_id >= ep->bdf_start &&
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dev_id <= ep->bdf_end) {
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epid = ((domain_nr - ep->segment_start) << 16) +
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dev_id - ep->bdf_start + ep->endpoint_id;
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return viot_dev_iommu_init(aliased_dev, ep->viommu,
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epid);
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}
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}
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return -ENODEV;
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}
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static int viot_mmio_dev_iommu_init(struct platform_device *pdev)
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{
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struct resource *mem;
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struct viot_endpoint *ep;
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mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (!mem)
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return -ENODEV;
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list_for_each_entry(ep, &viot_mmio_endpoints, list) {
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if (ep->address == mem->start)
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return viot_dev_iommu_init(&pdev->dev, ep->viommu,
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ep->endpoint_id);
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}
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return -ENODEV;
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}
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/**
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* viot_iommu_configure - Setup IOMMU ops for an endpoint described by VIOT
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* @dev: the endpoint
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*
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* Return: 0 on success, <0 on failure
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*/
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int viot_iommu_configure(struct device *dev)
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{
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if (dev_is_pci(dev))
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return pci_for_each_dma_alias(to_pci_dev(dev),
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||
|
|
viot_pci_dev_iommu_init, dev);
|
||
|
|
else if (dev_is_platform(dev))
|
||
|
|
return viot_mmio_dev_iommu_init(to_platform_device(dev));
|
||
|
|
return -ENODEV;
|
||
|
|
}
|