drivers/acpi/viot.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Virtual I/O topology
  *
  * The Virtual I/O Translation Table (VIOT) describes the topology of
  * para-virtual IOMMUs and the endpoints they manage. The OS uses it to
  * initialize devices in the right order, preventing endpoints from issuing DMA
  * before their IOMMU is ready.
  *
  * When binding a driver to a device, before calling the device driver's probe()
  * method, the driver infrastructure calls dma_configure(). At that point the
  * VIOT driver looks for an IOMMU associated to the device in the VIOT table.
  * If an IOMMU exists and has been initialized, the VIOT driver initializes the
  * device's IOMMU fwspec, allowing the DMA infrastructure to invoke the IOMMU
  * ops when the device driver configures DMA mappings. If an IOMMU exists and
  * hasn't yet been initialized, VIOT returns -EPROBE_DEFER to postpone probing
  * the device until the IOMMU is available.
  */
 #define pr_fmt(fmt) "ACPI: VIOT: " fmt

 #include <linux/acpi_viot.h>
 #include <linux/dma-iommu.h>
 #include <linux/fwnode.h>
 #include <linux/iommu.h>
 #include <linux/list.h>
 #include <linux/pci.h>
 #include <linux/platform_device.h>

 struct viot_iommu {
 	/* Node offset within the table */
 	unsigned int			offset;
 	struct fwnode_handle		*fwnode;
 	struct list_head		list;
 };

 struct viot_endpoint {
 	union {
 		/* PCI range */
 		struct {
 			u16		segment_start;
 			u16		segment_end;
 			u16		bdf_start;
 			u16		bdf_end;
 		};
 		/* MMIO */
 		u64			address;
 	};
 	u32				endpoint_id;
 	struct viot_iommu		*viommu;
 	struct list_head		list;
 };

 static struct acpi_table_viot *viot;
 static LIST_HEAD(viot_iommus);
 static LIST_HEAD(viot_pci_ranges);
 static LIST_HEAD(viot_mmio_endpoints);

 static int __init viot_check_bounds(const struct acpi_viot_header *hdr)
 {
 	struct acpi_viot_header *start, *end, *hdr_end;

 	start = ACPI_ADD_PTR(struct acpi_viot_header, viot,
 			     max_t(size_t, sizeof(*viot), viot->node_offset));
 	end = ACPI_ADD_PTR(struct acpi_viot_header, viot, viot->header.length);
 	hdr_end = ACPI_ADD_PTR(struct acpi_viot_header, hdr, sizeof(*hdr));

 	if (hdr < start || hdr_end > end) {
 		pr_err(FW_BUG "Node pointer overflows\n");
 		return -EOVERFLOW;
 	}
 	if (hdr->length < sizeof(*hdr)) {
 		pr_err(FW_BUG "Empty node\n");
 		return -EINVAL;
 	}
 	return 0;
 }

 static int __init viot_get_pci_iommu_fwnode(struct viot_iommu *viommu,
 					    u16 segment, u16 bdf)
 {
 	struct pci_dev *pdev;
 	struct fwnode_handle *fwnode;

 	pdev = pci_get_domain_bus_and_slot(segment, PCI_BUS_NUM(bdf),
 					   bdf & 0xff);
 	if (!pdev) {
 		pr_err("Could not find PCI IOMMU\n");
 		return -ENODEV;
 	}

 	fwnode = pdev->dev.fwnode;
 	if (!fwnode) {
 		/*
 		 * PCI devices aren't necessarily described by ACPI. Create a
 		 * fwnode so the IOMMU subsystem can identify this device.
 		 */
 		fwnode = acpi_alloc_fwnode_static();
 		if (!fwnode) {
 			pci_dev_put(pdev);
 			return -ENOMEM;
 		}
 		set_primary_fwnode(&pdev->dev, fwnode);
 	}
 	viommu->fwnode = pdev->dev.fwnode;
 	pci_dev_put(pdev);
 	return 0;
 }

 static int __init viot_get_mmio_iommu_fwnode(struct viot_iommu *viommu,
 					     u64 address)
 {
 	struct acpi_device *adev;
 	struct resource res = {
 		.start	= address,
 		.end	= address,
 		.flags	= IORESOURCE_MEM,
 	};

 	adev = acpi_resource_consumer(&res);
 	if (!adev) {
 		pr_err("Could not find MMIO IOMMU\n");
 		return -EINVAL;
 	}
 	viommu->fwnode = &adev->fwnode;
 	return 0;
 }

 static struct viot_iommu * __init viot_get_iommu(unsigned int offset)
 {
 	int ret;
 	struct viot_iommu *viommu;
 	struct acpi_viot_header *hdr = ACPI_ADD_PTR(struct acpi_viot_header,
 						    viot, offset);
 	union {
 		struct acpi_viot_virtio_iommu_pci pci;
 		struct acpi_viot_virtio_iommu_mmio mmio;
 	} *node = (void *)hdr;

 	list_for_each_entry(viommu, &viot_iommus, list)
 		if (viommu->offset == offset)
 			return viommu;

 	if (viot_check_bounds(hdr))
 		return NULL;

 	viommu = kzalloc(sizeof(*viommu), GFP_KERNEL);
 	if (!viommu)
 		return NULL;

 	viommu->offset = offset;
 	switch (hdr->type) {
 	case ACPI_VIOT_NODE_VIRTIO_IOMMU_PCI:
 		if (hdr->length < sizeof(node->pci))
 			goto err_free;

 		ret = viot_get_pci_iommu_fwnode(viommu, node->pci.segment,
 						node->pci.bdf);
 		break;
 	case ACPI_VIOT_NODE_VIRTIO_IOMMU_MMIO:
 		if (hdr->length < sizeof(node->mmio))
 			goto err_free;

 		ret = viot_get_mmio_iommu_fwnode(viommu,
 						 node->mmio.base_address);
 		break;
 	default:
 		ret = -EINVAL;
 	}
 	if (ret)
 		goto err_free;

 	list_add(&viommu->list, &viot_iommus);
 	return viommu;

 err_free:
 	kfree(viommu);
 	return NULL;
 }

 static int __init viot_parse_node(const struct acpi_viot_header *hdr)
 {
 	int ret = -EINVAL;
 	struct list_head *list;
 	struct viot_endpoint *ep;
 	union {
 		struct acpi_viot_mmio mmio;
 		struct acpi_viot_pci_range pci;
 	} *node = (void *)hdr;

 	if (viot_check_bounds(hdr))
 		return -EINVAL;

 	if (hdr->type == ACPI_VIOT_NODE_VIRTIO_IOMMU_PCI ||
 	    hdr->type == ACPI_VIOT_NODE_VIRTIO_IOMMU_MMIO)
 		return 0;

 	ep = kzalloc(sizeof(*ep), GFP_KERNEL);
 	if (!ep)
 		return -ENOMEM;

 	switch (hdr->type) {
 	case ACPI_VIOT_NODE_PCI_RANGE:
 		if (hdr->length < sizeof(node->pci)) {
 			pr_err(FW_BUG "Invalid PCI node size\n");
 			goto err_free;
 		}

 		ep->segment_start = node->pci.segment_start;
 		ep->segment_end = node->pci.segment_end;
 		ep->bdf_start = node->pci.bdf_start;
 		ep->bdf_end = node->pci.bdf_end;
 		ep->endpoint_id = node->pci.endpoint_start;
 		ep->viommu = viot_get_iommu(node->pci.output_node);
 		list = &viot_pci_ranges;
 		break;
 	case ACPI_VIOT_NODE_MMIO:
 		if (hdr->length < sizeof(node->mmio)) {
 			pr_err(FW_BUG "Invalid MMIO node size\n");
 			goto err_free;
 		}

 		ep->address = node->mmio.base_address;
 		ep->endpoint_id = node->mmio.endpoint;
 		ep->viommu = viot_get_iommu(node->mmio.output_node);
 		list = &viot_mmio_endpoints;
 		break;
 	default:
 		pr_warn("Unsupported node %x\n", hdr->type);
 		ret = 0;
 		goto err_free;
 	}

 	if (!ep->viommu) {
 		pr_warn("No IOMMU node found\n");
 		/*
 		 * A future version of the table may use the node for other
 		 * purposes. Keep parsing.
 		 */
 		ret = 0;
 		goto err_free;
 	}

 	list_add(&ep->list, list);
 	return 0;

 err_free:
 	kfree(ep);
 	return ret;
 }

 /**
  * acpi_viot_init - Parse the VIOT table
  *
  * Parse the VIOT table, prepare the list of endpoints to be used during DMA
  * setup of devices.
  */
 void __init acpi_viot_init(void)
 {
 	int i;
 	acpi_status status;
 	struct acpi_table_header *hdr;
 	struct acpi_viot_header *node;

 	status = acpi_get_table(ACPI_SIG_VIOT, 0, &hdr);
 	if (ACPI_FAILURE(status)) {
 		if (status != AE_NOT_FOUND) {
 			const char *msg = acpi_format_exception(status);

 			pr_err("Failed to get table, %s\n", msg);
 		}
 		return;
 	}

 	viot = (void *)hdr;

 	node = ACPI_ADD_PTR(struct acpi_viot_header, viot, viot->node_offset);
 	for (i = 0; i < viot->node_count; i++) {
 		if (viot_parse_node(node))
 			return;

 		node = ACPI_ADD_PTR(struct acpi_viot_header, node,
 				    node->length);
 	}

 	acpi_put_table(hdr);
 }

 static int viot_dev_iommu_init(struct device *dev, struct viot_iommu *viommu,
 			       u32 epid)
 {
 	const struct iommu_ops *ops;

 	if (!viommu)
 		return -ENODEV;

 	/* We're not translating ourself */
 	if (viommu->fwnode == dev->fwnode)
 		return -EINVAL;

 	ops = iommu_ops_from_fwnode(viommu->fwnode);
 	if (!ops)
 		return IS_ENABLED(CONFIG_VIRTIO_IOMMU) ?
 			-EPROBE_DEFER : -ENODEV;

 	return acpi_iommu_fwspec_init(dev, epid, viommu->fwnode, ops);
 }

 static int viot_pci_dev_iommu_init(struct pci_dev *pdev, u16 dev_id, void *data)
 {
 	u32 epid;
 	struct viot_endpoint *ep;
 	u32 domain_nr = pci_domain_nr(pdev->bus);

 	list_for_each_entry(ep, &viot_pci_ranges, list) {
 		if (domain_nr >= ep->segment_start &&
 		    domain_nr <= ep->segment_end &&
 		    dev_id >= ep->bdf_start &&
 		    dev_id <= ep->bdf_end) {
 			epid = ((domain_nr - ep->segment_start) << 16) +
 				dev_id - ep->bdf_start + ep->endpoint_id;

 			/*
 			 * If we found a PCI range managed by the viommu, we're
 			 * the one that has to request ACS.
 			 */
 			pci_request_acs();

 			return viot_dev_iommu_init(&pdev->dev, ep->viommu,
 						   epid);
 		}
 	}
 	return -ENODEV;
 }

 static int viot_mmio_dev_iommu_init(struct platform_device *pdev)
 {
 	struct resource *mem;
 	struct viot_endpoint *ep;

 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!mem)
 		return -ENODEV;

 	list_for_each_entry(ep, &viot_mmio_endpoints, list) {
 		if (ep->address == mem->start)
 			return viot_dev_iommu_init(&pdev->dev, ep->viommu,
 						   ep->endpoint_id);
 	}
 	return -ENODEV;
 }

 /**
  * viot_iommu_configure - Setup IOMMU ops for an endpoint described by VIOT
  * @dev: the endpoint
  *
  * Return: 0 on success, <0 on failure
  */
 int viot_iommu_configure(struct device *dev)
 {
 	if (dev_is_pci(dev))
 		return pci_for_each_dma_alias(to_pci_dev(dev),
 					      viot_pci_dev_iommu_init, NULL);
 	else if (dev_is_platform(dev))
 		return viot_mmio_dev_iommu_init(to_platform_device(dev));
 	return -ENODEV;
 }
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Virtual I/O topology
	*
	* The Virtual I/O Translation Table (VIOT) describes the topology of
	* para-virtual IOMMUs and the endpoints they manage. The OS uses it to
	* initialize devices in the right order, preventing endpoints from issuing DMA
	* before their IOMMU is ready.
	*
	* When binding a driver to a device, before calling the device driver's probe()
	* method, the driver infrastructure calls dma_configure(). At that point the
	* VIOT driver looks for an IOMMU associated to the device in the VIOT table.
	* If an IOMMU exists and has been initialized, the VIOT driver initializes the
	* device's IOMMU fwspec, allowing the DMA infrastructure to invoke the IOMMU
	* ops when the device driver configures DMA mappings. If an IOMMU exists and
	* hasn't yet been initialized, VIOT returns -EPROBE_DEFER to postpone probing
	* the device until the IOMMU is available.
	*/
	#define pr_fmt(fmt) "ACPI: VIOT: " fmt

	#include <linux/acpi_viot.h>
	#include <linux/dma-iommu.h>
	#include <linux/fwnode.h>
	#include <linux/iommu.h>
	#include <linux/list.h>
	#include <linux/pci.h>
	#include <linux/platform_device.h>

	struct viot_iommu {
	/* Node offset within the table */
	unsigned int offset;
	struct fwnode_handle *fwnode;
	struct list_head list;
	};

	struct viot_endpoint {
	union {
	/* PCI range */
	struct {
	u16 segment_start;
	u16 segment_end;
	u16 bdf_start;
	u16 bdf_end;
	};
	/* MMIO */
	u64 address;
	};
	u32 endpoint_id;
	struct viot_iommu *viommu;
	struct list_head list;
	};

	static struct acpi_table_viot *viot;
	static LIST_HEAD(viot_iommus);
	static LIST_HEAD(viot_pci_ranges);
	static LIST_HEAD(viot_mmio_endpoints);

	static int __init viot_check_bounds(const struct acpi_viot_header *hdr)
	{
	struct acpi_viot_header start, end, *hdr_end;

	start = ACPI_ADD_PTR(struct acpi_viot_header, viot,
	max_t(size_t, sizeof(*viot), viot->node_offset));
	end = ACPI_ADD_PTR(struct acpi_viot_header, viot, viot->header.length);
	hdr_end = ACPI_ADD_PTR(struct acpi_viot_header, hdr, sizeof(*hdr));

	if (hdr < start \|\| hdr_end > end) {
	pr_err(FW_BUG "Node pointer overflows\n");
	return -EOVERFLOW;
	}
	if (hdr->length < sizeof(*hdr)) {
	pr_err(FW_BUG "Empty node\n");
	return -EINVAL;
	}
	return 0;
	}

	static int __init viot_get_pci_iommu_fwnode(struct viot_iommu *viommu,
	u16 segment, u16 bdf)
	{
	struct pci_dev *pdev;
	struct fwnode_handle *fwnode;

	pdev = pci_get_domain_bus_and_slot(segment, PCI_BUS_NUM(bdf),
	bdf & 0xff);
	if (!pdev) {
	pr_err("Could not find PCI IOMMU\n");
	return -ENODEV;
	}

	fwnode = pdev->dev.fwnode;
	if (!fwnode) {
	/*
	* PCI devices aren't necessarily described by ACPI. Create a
	* fwnode so the IOMMU subsystem can identify this device.
	*/
	fwnode = acpi_alloc_fwnode_static();
	if (!fwnode) {
	pci_dev_put(pdev);
	return -ENOMEM;
	}
	set_primary_fwnode(&pdev->dev, fwnode);
	}
	viommu->fwnode = pdev->dev.fwnode;
	pci_dev_put(pdev);
	return 0;
	}

	static int __init viot_get_mmio_iommu_fwnode(struct viot_iommu *viommu,
	u64 address)
	{
	struct acpi_device *adev;
	struct resource res = {
	.start = address,
	.end = address,
	.flags = IORESOURCE_MEM,
	};

	adev = acpi_resource_consumer(&res);
	if (!adev) {
	pr_err("Could not find MMIO IOMMU\n");
	return -EINVAL;
	}
	viommu->fwnode = &adev->fwnode;
	return 0;
	}

	static struct viot_iommu * __init viot_get_iommu(unsigned int offset)
	{
	int ret;
	struct viot_iommu *viommu;
	struct acpi_viot_header *hdr = ACPI_ADD_PTR(struct acpi_viot_header,
	viot, offset);
	union {
	struct acpi_viot_virtio_iommu_pci pci;
	struct acpi_viot_virtio_iommu_mmio mmio;
	} node = (void )hdr;

	list_for_each_entry(viommu, &viot_iommus, list)
	if (viommu->offset == offset)
	return viommu;

	if (viot_check_bounds(hdr))
	return NULL;

	viommu = kzalloc(sizeof(*viommu), GFP_KERNEL);
	if (!viommu)
	return NULL;

	viommu->offset = offset;
	switch (hdr->type) {
	case ACPI_VIOT_NODE_VIRTIO_IOMMU_PCI:
	if (hdr->length < sizeof(node->pci))
	goto err_free;

	ret = viot_get_pci_iommu_fwnode(viommu, node->pci.segment,
	node->pci.bdf);
	break;
	case ACPI_VIOT_NODE_VIRTIO_IOMMU_MMIO:
	if (hdr->length < sizeof(node->mmio))
	goto err_free;

	ret = viot_get_mmio_iommu_fwnode(viommu,
	node->mmio.base_address);
	break;
	default:
	ret = -EINVAL;
	}
	if (ret)
	goto err_free;

	list_add(&viommu->list, &viot_iommus);
	return viommu;

	err_free:
	kfree(viommu);
	return NULL;
	}

	static int __init viot_parse_node(const struct acpi_viot_header *hdr)
	{
	int ret = -EINVAL;
	struct list_head *list;
	struct viot_endpoint *ep;
	union {
	struct acpi_viot_mmio mmio;
	struct acpi_viot_pci_range pci;
	} node = (void )hdr;

	if (viot_check_bounds(hdr))
	return -EINVAL;

	if (hdr->type == ACPI_VIOT_NODE_VIRTIO_IOMMU_PCI \|\|
	hdr->type == ACPI_VIOT_NODE_VIRTIO_IOMMU_MMIO)
	return 0;

	ep = kzalloc(sizeof(*ep), GFP_KERNEL);
	if (!ep)
	return -ENOMEM;

	switch (hdr->type) {
	case ACPI_VIOT_NODE_PCI_RANGE:
	if (hdr->length < sizeof(node->pci)) {
	pr_err(FW_BUG "Invalid PCI node size\n");
	goto err_free;
	}

	ep->segment_start = node->pci.segment_start;
	ep->segment_end = node->pci.segment_end;
	ep->bdf_start = node->pci.bdf_start;
	ep->bdf_end = node->pci.bdf_end;
	ep->endpoint_id = node->pci.endpoint_start;
	ep->viommu = viot_get_iommu(node->pci.output_node);
	list = &viot_pci_ranges;
	break;
	case ACPI_VIOT_NODE_MMIO:
	if (hdr->length < sizeof(node->mmio)) {
	pr_err(FW_BUG "Invalid MMIO node size\n");
	goto err_free;
	}

	ep->address = node->mmio.base_address;
	ep->endpoint_id = node->mmio.endpoint;
	ep->viommu = viot_get_iommu(node->mmio.output_node);
	list = &viot_mmio_endpoints;
	break;
	default:
	pr_warn("Unsupported node %x\n", hdr->type);
	ret = 0;
	goto err_free;
	}

	if (!ep->viommu) {
	pr_warn("No IOMMU node found\n");
	/*
	* A future version of the table may use the node for other
	* purposes. Keep parsing.
	*/
	ret = 0;
	goto err_free;
	}

	list_add(&ep->list, list);
	return 0;

	err_free:
	kfree(ep);
	return ret;
	}

	/**
	* acpi_viot_init - Parse the VIOT table
	*
	* Parse the VIOT table, prepare the list of endpoints to be used during DMA
	* setup of devices.
	*/
	void __init acpi_viot_init(void)
	{
	int i;
	acpi_status status;
	struct acpi_table_header *hdr;
	struct acpi_viot_header *node;

	status = acpi_get_table(ACPI_SIG_VIOT, 0, &hdr);
	if (ACPI_FAILURE(status)) {
	if (status != AE_NOT_FOUND) {
	const char *msg = acpi_format_exception(status);

	pr_err("Failed to get table, %s\n", msg);
	}
	return;
	}

	viot = (void *)hdr;

	node = ACPI_ADD_PTR(struct acpi_viot_header, viot, viot->node_offset);
	for (i = 0; i < viot->node_count; i++) {
	if (viot_parse_node(node))
	return;

	node = ACPI_ADD_PTR(struct acpi_viot_header, node,
	node->length);
	}

	acpi_put_table(hdr);
	}

	static int viot_dev_iommu_init(struct device dev, struct viot_iommu viommu,
	u32 epid)
	{
	const struct iommu_ops *ops;

	if (!viommu)
	return -ENODEV;

	/* We're not translating ourself */
	if (viommu->fwnode == dev->fwnode)
	return -EINVAL;

	ops = iommu_ops_from_fwnode(viommu->fwnode);
	if (!ops)
	return IS_ENABLED(CONFIG_VIRTIO_IOMMU) ?
	-EPROBE_DEFER : -ENODEV;

	return acpi_iommu_fwspec_init(dev, epid, viommu->fwnode, ops);
	}

	static int viot_pci_dev_iommu_init(struct pci_dev pdev, u16 dev_id, void data)
	{
	u32 epid;
	struct viot_endpoint *ep;
	u32 domain_nr = pci_domain_nr(pdev->bus);

	list_for_each_entry(ep, &viot_pci_ranges, list) {
	if (domain_nr >= ep->segment_start &&
	domain_nr <= ep->segment_end &&
	dev_id >= ep->bdf_start &&
	dev_id <= ep->bdf_end) {
	epid = ((domain_nr - ep->segment_start) << 16) +
	dev_id - ep->bdf_start + ep->endpoint_id;

	/*
	* If we found a PCI range managed by the viommu, we're
	* the one that has to request ACS.
	*/
	pci_request_acs();

	return viot_dev_iommu_init(&pdev->dev, ep->viommu,
	epid);
	}
	}
	return -ENODEV;
	}

	static int viot_mmio_dev_iommu_init(struct platform_device *pdev)
	{
	struct resource *mem;
	struct viot_endpoint *ep;

	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!mem)
	return -ENODEV;

	list_for_each_entry(ep, &viot_mmio_endpoints, list) {
	if (ep->address == mem->start)
	return viot_dev_iommu_init(&pdev->dev, ep->viommu,
	ep->endpoint_id);
	}
	return -ENODEV;
	}

	/**
	* viot_iommu_configure - Setup IOMMU ops for an endpoint described by VIOT
	* @dev: the endpoint
	*
	* Return: 0 on success, <0 on failure
	*/
	int viot_iommu_configure(struct device *dev)
	{
	if (dev_is_pci(dev))
	return pci_for_each_dma_alias(to_pci_dev(dev),
	viot_pci_dev_iommu_init, NULL);
	else if (dev_is_platform(dev))
	return viot_mmio_dev_iommu_init(to_platform_device(dev));
	return -ENODEV;
	}