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![Niklas Schnelle](/assets/img/avatar_default.png)
The entries in the DMA translation tables for our IOMMU must specify physical addresses of either the next level table or the final page to be mapped for DMA. Currently however the code simply passes the virtual addresses of both. On the other hand we still need to walk the tables via their virtual addresses so we need to do a phys_to_virt() when setting the entries and a virt_to_phys() when getting them. Similarly when passing the I/O translation anchor to the hardware we must also specify its physical address. As the DMA and IOMMU APIs we are implementing already use the correct phys_addr_t type for the address to be mapped let's also thread this through instead of treating it as just an unsigned long. Note: this currently doesn't fix a real bug, since virtual addresses are indentical to physical ones. Reviewed-by: Pierre Morel <pmorel@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
382 lines
9.3 KiB
C
382 lines
9.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* IOMMU API for s390 PCI devices
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*
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* Copyright IBM Corp. 2015
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* Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
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*/
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#include <linux/pci.h>
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#include <linux/iommu.h>
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#include <linux/iommu-helper.h>
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#include <linux/sizes.h>
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#include <asm/pci_dma.h>
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/*
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* Physically contiguous memory regions can be mapped with 4 KiB alignment,
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* we allow all page sizes that are an order of 4KiB (no special large page
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* support so far).
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*/
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#define S390_IOMMU_PGSIZES (~0xFFFUL)
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static const struct iommu_ops s390_iommu_ops;
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struct s390_domain {
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struct iommu_domain domain;
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struct list_head devices;
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unsigned long *dma_table;
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spinlock_t dma_table_lock;
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spinlock_t list_lock;
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};
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struct s390_domain_device {
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struct list_head list;
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struct zpci_dev *zdev;
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};
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static struct s390_domain *to_s390_domain(struct iommu_domain *dom)
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{
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return container_of(dom, struct s390_domain, domain);
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}
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static bool s390_iommu_capable(enum iommu_cap cap)
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{
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switch (cap) {
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case IOMMU_CAP_CACHE_COHERENCY:
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return true;
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case IOMMU_CAP_INTR_REMAP:
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return true;
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default:
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return false;
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}
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}
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static struct iommu_domain *s390_domain_alloc(unsigned domain_type)
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{
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struct s390_domain *s390_domain;
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if (domain_type != IOMMU_DOMAIN_UNMANAGED)
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return NULL;
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s390_domain = kzalloc(sizeof(*s390_domain), GFP_KERNEL);
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if (!s390_domain)
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return NULL;
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s390_domain->dma_table = dma_alloc_cpu_table();
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if (!s390_domain->dma_table) {
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kfree(s390_domain);
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return NULL;
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}
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spin_lock_init(&s390_domain->dma_table_lock);
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spin_lock_init(&s390_domain->list_lock);
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INIT_LIST_HEAD(&s390_domain->devices);
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return &s390_domain->domain;
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}
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static void s390_domain_free(struct iommu_domain *domain)
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{
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struct s390_domain *s390_domain = to_s390_domain(domain);
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dma_cleanup_tables(s390_domain->dma_table);
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kfree(s390_domain);
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}
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static int s390_iommu_attach_device(struct iommu_domain *domain,
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struct device *dev)
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{
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struct s390_domain *s390_domain = to_s390_domain(domain);
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struct zpci_dev *zdev = to_zpci_dev(dev);
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struct s390_domain_device *domain_device;
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unsigned long flags;
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int cc, rc;
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if (!zdev)
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return -ENODEV;
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domain_device = kzalloc(sizeof(*domain_device), GFP_KERNEL);
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if (!domain_device)
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return -ENOMEM;
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if (zdev->dma_table) {
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cc = zpci_dma_exit_device(zdev);
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if (cc) {
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rc = -EIO;
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goto out_free;
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}
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}
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zdev->dma_table = s390_domain->dma_table;
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cc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
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virt_to_phys(zdev->dma_table));
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if (cc) {
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rc = -EIO;
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goto out_restore;
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}
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spin_lock_irqsave(&s390_domain->list_lock, flags);
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/* First device defines the DMA range limits */
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if (list_empty(&s390_domain->devices)) {
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domain->geometry.aperture_start = zdev->start_dma;
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domain->geometry.aperture_end = zdev->end_dma;
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domain->geometry.force_aperture = true;
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/* Allow only devices with identical DMA range limits */
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} else if (domain->geometry.aperture_start != zdev->start_dma ||
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domain->geometry.aperture_end != zdev->end_dma) {
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rc = -EINVAL;
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spin_unlock_irqrestore(&s390_domain->list_lock, flags);
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goto out_restore;
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}
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domain_device->zdev = zdev;
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zdev->s390_domain = s390_domain;
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list_add(&domain_device->list, &s390_domain->devices);
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spin_unlock_irqrestore(&s390_domain->list_lock, flags);
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return 0;
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out_restore:
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zpci_dma_init_device(zdev);
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out_free:
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kfree(domain_device);
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return rc;
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}
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static void s390_iommu_detach_device(struct iommu_domain *domain,
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struct device *dev)
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{
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struct s390_domain *s390_domain = to_s390_domain(domain);
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struct zpci_dev *zdev = to_zpci_dev(dev);
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struct s390_domain_device *domain_device, *tmp;
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unsigned long flags;
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int found = 0;
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if (!zdev)
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return;
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spin_lock_irqsave(&s390_domain->list_lock, flags);
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list_for_each_entry_safe(domain_device, tmp, &s390_domain->devices,
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list) {
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if (domain_device->zdev == zdev) {
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list_del(&domain_device->list);
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kfree(domain_device);
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found = 1;
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break;
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}
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}
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spin_unlock_irqrestore(&s390_domain->list_lock, flags);
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if (found) {
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zdev->s390_domain = NULL;
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zpci_unregister_ioat(zdev, 0);
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zpci_dma_init_device(zdev);
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}
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}
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static struct iommu_device *s390_iommu_probe_device(struct device *dev)
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{
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struct zpci_dev *zdev = to_zpci_dev(dev);
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return &zdev->iommu_dev;
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}
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static void s390_iommu_release_device(struct device *dev)
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{
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struct zpci_dev *zdev = to_zpci_dev(dev);
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struct iommu_domain *domain;
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/*
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* This is a workaround for a scenario where the IOMMU API common code
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* "forgets" to call the detach_dev callback: After binding a device
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* to vfio-pci and completing the VFIO_SET_IOMMU ioctl (which triggers
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* the attach_dev), removing the device via
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* "echo 1 > /sys/bus/pci/devices/.../remove" won't trigger detach_dev,
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* only release_device will be called via the BUS_NOTIFY_REMOVED_DEVICE
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* notifier.
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*
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* So let's call detach_dev from here if it hasn't been called before.
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*/
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if (zdev && zdev->s390_domain) {
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domain = iommu_get_domain_for_dev(dev);
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if (domain)
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s390_iommu_detach_device(domain, dev);
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}
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}
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static int s390_iommu_update_trans(struct s390_domain *s390_domain,
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phys_addr_t pa, dma_addr_t dma_addr,
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size_t size, int flags)
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{
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struct s390_domain_device *domain_device;
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phys_addr_t page_addr = pa & PAGE_MASK;
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dma_addr_t start_dma_addr = dma_addr;
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unsigned long irq_flags, nr_pages, i;
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unsigned long *entry;
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int rc = 0;
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if (dma_addr < s390_domain->domain.geometry.aperture_start ||
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dma_addr + size > s390_domain->domain.geometry.aperture_end)
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return -EINVAL;
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nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
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if (!nr_pages)
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return 0;
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spin_lock_irqsave(&s390_domain->dma_table_lock, irq_flags);
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for (i = 0; i < nr_pages; i++) {
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entry = dma_walk_cpu_trans(s390_domain->dma_table, dma_addr);
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if (!entry) {
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rc = -ENOMEM;
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goto undo_cpu_trans;
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}
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dma_update_cpu_trans(entry, page_addr, flags);
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page_addr += PAGE_SIZE;
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dma_addr += PAGE_SIZE;
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}
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spin_lock(&s390_domain->list_lock);
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list_for_each_entry(domain_device, &s390_domain->devices, list) {
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rc = zpci_refresh_trans((u64) domain_device->zdev->fh << 32,
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start_dma_addr, nr_pages * PAGE_SIZE);
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if (rc)
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break;
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}
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spin_unlock(&s390_domain->list_lock);
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undo_cpu_trans:
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if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)) {
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flags = ZPCI_PTE_INVALID;
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while (i-- > 0) {
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page_addr -= PAGE_SIZE;
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dma_addr -= PAGE_SIZE;
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entry = dma_walk_cpu_trans(s390_domain->dma_table,
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dma_addr);
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if (!entry)
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break;
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dma_update_cpu_trans(entry, page_addr, flags);
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}
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}
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spin_unlock_irqrestore(&s390_domain->dma_table_lock, irq_flags);
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return rc;
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}
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static int s390_iommu_map(struct iommu_domain *domain, unsigned long iova,
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phys_addr_t paddr, size_t size, int prot, gfp_t gfp)
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{
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struct s390_domain *s390_domain = to_s390_domain(domain);
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int flags = ZPCI_PTE_VALID, rc = 0;
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if (!(prot & IOMMU_READ))
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return -EINVAL;
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if (!(prot & IOMMU_WRITE))
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flags |= ZPCI_TABLE_PROTECTED;
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rc = s390_iommu_update_trans(s390_domain, paddr, iova,
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size, flags);
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return rc;
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}
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static phys_addr_t s390_iommu_iova_to_phys(struct iommu_domain *domain,
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dma_addr_t iova)
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{
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struct s390_domain *s390_domain = to_s390_domain(domain);
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unsigned long *sto, *pto, *rto, flags;
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unsigned int rtx, sx, px;
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phys_addr_t phys = 0;
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if (iova < domain->geometry.aperture_start ||
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iova > domain->geometry.aperture_end)
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return 0;
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rtx = calc_rtx(iova);
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sx = calc_sx(iova);
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px = calc_px(iova);
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rto = s390_domain->dma_table;
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spin_lock_irqsave(&s390_domain->dma_table_lock, flags);
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if (rto && reg_entry_isvalid(rto[rtx])) {
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sto = get_rt_sto(rto[rtx]);
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if (sto && reg_entry_isvalid(sto[sx])) {
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pto = get_st_pto(sto[sx]);
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if (pto && pt_entry_isvalid(pto[px]))
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phys = pto[px] & ZPCI_PTE_ADDR_MASK;
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}
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}
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spin_unlock_irqrestore(&s390_domain->dma_table_lock, flags);
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return phys;
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}
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static size_t s390_iommu_unmap(struct iommu_domain *domain,
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unsigned long iova, size_t size,
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struct iommu_iotlb_gather *gather)
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{
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struct s390_domain *s390_domain = to_s390_domain(domain);
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int flags = ZPCI_PTE_INVALID;
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phys_addr_t paddr;
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int rc;
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paddr = s390_iommu_iova_to_phys(domain, iova);
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if (!paddr)
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return 0;
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rc = s390_iommu_update_trans(s390_domain, paddr, iova,
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size, flags);
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if (rc)
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return 0;
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return size;
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}
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int zpci_init_iommu(struct zpci_dev *zdev)
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{
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int rc = 0;
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rc = iommu_device_sysfs_add(&zdev->iommu_dev, NULL, NULL,
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"s390-iommu.%08x", zdev->fid);
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if (rc)
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goto out_err;
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rc = iommu_device_register(&zdev->iommu_dev, &s390_iommu_ops, NULL);
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if (rc)
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goto out_sysfs;
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return 0;
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out_sysfs:
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iommu_device_sysfs_remove(&zdev->iommu_dev);
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out_err:
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return rc;
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}
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void zpci_destroy_iommu(struct zpci_dev *zdev)
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{
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iommu_device_unregister(&zdev->iommu_dev);
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iommu_device_sysfs_remove(&zdev->iommu_dev);
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}
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static const struct iommu_ops s390_iommu_ops = {
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.capable = s390_iommu_capable,
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.domain_alloc = s390_domain_alloc,
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.domain_free = s390_domain_free,
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.attach_dev = s390_iommu_attach_device,
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.detach_dev = s390_iommu_detach_device,
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.map = s390_iommu_map,
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.unmap = s390_iommu_unmap,
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.iova_to_phys = s390_iommu_iova_to_phys,
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.probe_device = s390_iommu_probe_device,
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.release_device = s390_iommu_release_device,
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.device_group = generic_device_group,
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.pgsize_bitmap = S390_IOMMU_PGSIZES,
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};
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static int __init s390_iommu_init(void)
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{
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return bus_set_iommu(&pci_bus_type, &s390_iommu_ops);
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}
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subsys_initcall(s390_iommu_init);
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