iommu/s390: Add iommu api for s390 pci devices
This adds an IOMMU API implementation for s390 PCI devices.
Reviewed-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c
new file mode 100644
index 0000000..cbe198c
--- /dev/null
+++ b/drivers/iommu/s390-iommu.c
@@ -0,0 +1,337 @@
+/*
+ * IOMMU API for s390 PCI devices
+ *
+ * Copyright IBM Corp. 2015
+ * Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
+ */
+
+#include <linux/pci.h>
+#include <linux/iommu.h>
+#include <linux/iommu-helper.h>
+#include <linux/pci.h>
+#include <linux/sizes.h>
+#include <asm/pci_dma.h>
+
+/*
+ * Physically contiguous memory regions can be mapped with 4 KiB alignment,
+ * we allow all page sizes that are an order of 4KiB (no special large page
+ * support so far).
+ */
+#define S390_IOMMU_PGSIZES (~0xFFFUL)
+
+struct s390_domain {
+ struct iommu_domain domain;
+ struct list_head devices;
+ unsigned long *dma_table;
+ spinlock_t dma_table_lock;
+ spinlock_t list_lock;
+};
+
+struct s390_domain_device {
+ struct list_head list;
+ struct zpci_dev *zdev;
+};
+
+static struct s390_domain *to_s390_domain(struct iommu_domain *dom)
+{
+ return container_of(dom, struct s390_domain, domain);
+}
+
+static bool s390_iommu_capable(enum iommu_cap cap)
+{
+ switch (cap) {
+ case IOMMU_CAP_CACHE_COHERENCY:
+ return true;
+ case IOMMU_CAP_INTR_REMAP:
+ return true;
+ default:
+ return false;
+ }
+}
+
+struct iommu_domain *s390_domain_alloc(unsigned domain_type)
+{
+ struct s390_domain *s390_domain;
+
+ if (domain_type != IOMMU_DOMAIN_UNMANAGED)
+ return NULL;
+
+ s390_domain = kzalloc(sizeof(*s390_domain), GFP_KERNEL);
+ if (!s390_domain)
+ return NULL;
+
+ s390_domain->dma_table = dma_alloc_cpu_table();
+ if (!s390_domain->dma_table) {
+ kfree(s390_domain);
+ return NULL;
+ }
+
+ spin_lock_init(&s390_domain->dma_table_lock);
+ spin_lock_init(&s390_domain->list_lock);
+ INIT_LIST_HEAD(&s390_domain->devices);
+
+ return &s390_domain->domain;
+}
+
+void s390_domain_free(struct iommu_domain *domain)
+{
+ struct s390_domain *s390_domain = to_s390_domain(domain);
+
+ dma_cleanup_tables(s390_domain->dma_table);
+ kfree(s390_domain);
+}
+
+static int s390_iommu_attach_device(struct iommu_domain *domain,
+ struct device *dev)
+{
+ struct s390_domain *s390_domain = to_s390_domain(domain);
+ struct zpci_dev *zdev = to_pci_dev(dev)->sysdata;
+ struct s390_domain_device *domain_device;
+ unsigned long flags;
+ int rc;
+
+ if (!zdev)
+ return -ENODEV;
+
+ domain_device = kzalloc(sizeof(*domain_device), GFP_KERNEL);
+ if (!domain_device)
+ return -ENOMEM;
+
+ if (zdev->dma_table)
+ zpci_dma_exit_device(zdev);
+
+ zdev->dma_table = s390_domain->dma_table;
+ rc = zpci_register_ioat(zdev, 0, zdev->start_dma + PAGE_OFFSET,
+ zdev->start_dma + zdev->iommu_size - 1,
+ (u64) zdev->dma_table);
+ if (rc)
+ goto out_restore;
+
+ spin_lock_irqsave(&s390_domain->list_lock, flags);
+ /* First device defines the DMA range limits */
+ if (list_empty(&s390_domain->devices)) {
+ domain->geometry.aperture_start = zdev->start_dma;
+ domain->geometry.aperture_end = zdev->end_dma;
+ domain->geometry.force_aperture = true;
+ /* Allow only devices with identical DMA range limits */
+ } else if (domain->geometry.aperture_start != zdev->start_dma ||
+ domain->geometry.aperture_end != zdev->end_dma) {
+ rc = -EINVAL;
+ spin_unlock_irqrestore(&s390_domain->list_lock, flags);
+ goto out_restore;
+ }
+ domain_device->zdev = zdev;
+ zdev->s390_domain = s390_domain;
+ list_add(&domain_device->list, &s390_domain->devices);
+ spin_unlock_irqrestore(&s390_domain->list_lock, flags);
+
+ return 0;
+
+out_restore:
+ zpci_dma_init_device(zdev);
+ kfree(domain_device);
+
+ return rc;
+}
+
+static void s390_iommu_detach_device(struct iommu_domain *domain,
+ struct device *dev)
+{
+ struct s390_domain *s390_domain = to_s390_domain(domain);
+ struct zpci_dev *zdev = to_pci_dev(dev)->sysdata;
+ struct s390_domain_device *domain_device, *tmp;
+ unsigned long flags;
+ int found = 0;
+
+ if (!zdev)
+ return;
+
+ spin_lock_irqsave(&s390_domain->list_lock, flags);
+ list_for_each_entry_safe(domain_device, tmp, &s390_domain->devices,
+ list) {
+ if (domain_device->zdev == zdev) {
+ list_del(&domain_device->list);
+ kfree(domain_device);
+ found = 1;
+ break;
+ }
+ }
+ spin_unlock_irqrestore(&s390_domain->list_lock, flags);
+
+ if (found) {
+ zdev->s390_domain = NULL;
+ zpci_unregister_ioat(zdev, 0);
+ zpci_dma_init_device(zdev);
+ }
+}
+
+static int s390_iommu_add_device(struct device *dev)
+{
+ struct iommu_group *group;
+ int rc;
+
+ group = iommu_group_get(dev);
+ if (!group) {
+ group = iommu_group_alloc();
+ if (IS_ERR(group))
+ return PTR_ERR(group);
+ }
+
+ rc = iommu_group_add_device(group, dev);
+ iommu_group_put(group);
+
+ return rc;
+}
+
+static void s390_iommu_remove_device(struct device *dev)
+{
+ struct zpci_dev *zdev = to_pci_dev(dev)->sysdata;
+ struct iommu_domain *domain;
+
+ /*
+ * This is a workaround for a scenario where the IOMMU API common code
+ * "forgets" to call the detach_dev callback: After binding a device
+ * to vfio-pci and completing the VFIO_SET_IOMMU ioctl (which triggers
+ * the attach_dev), removing the device via
+ * "echo 1 > /sys/bus/pci/devices/.../remove" won't trigger detach_dev,
+ * only remove_device will be called via the BUS_NOTIFY_REMOVED_DEVICE
+ * notifier.
+ *
+ * So let's call detach_dev from here if it hasn't been called before.
+ */
+ if (zdev && zdev->s390_domain) {
+ domain = iommu_get_domain_for_dev(dev);
+ if (domain)
+ s390_iommu_detach_device(domain, dev);
+ }
+
+ iommu_group_remove_device(dev);
+}
+
+static int s390_iommu_update_trans(struct s390_domain *s390_domain,
+ unsigned long pa, dma_addr_t dma_addr,
+ size_t size, int flags)
+{
+ struct s390_domain_device *domain_device;
+ u8 *page_addr = (u8 *) (pa & PAGE_MASK);
+ dma_addr_t start_dma_addr = dma_addr;
+ unsigned long irq_flags, nr_pages, i;
+ int rc = 0;
+
+ if (dma_addr < s390_domain->domain.geometry.aperture_start ||
+ dma_addr + size > s390_domain->domain.geometry.aperture_end)
+ return -EINVAL;
+
+ nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
+ if (!nr_pages)
+ return 0;
+
+ spin_lock_irqsave(&s390_domain->dma_table_lock, irq_flags);
+ for (i = 0; i < nr_pages; i++) {
+ dma_update_cpu_trans(s390_domain->dma_table, page_addr,
+ dma_addr, flags);
+ page_addr += PAGE_SIZE;
+ dma_addr += PAGE_SIZE;
+ }
+
+ spin_lock(&s390_domain->list_lock);
+ list_for_each_entry(domain_device, &s390_domain->devices, list) {
+ rc = zpci_refresh_trans((u64) domain_device->zdev->fh << 32,
+ start_dma_addr, nr_pages * PAGE_SIZE);
+ if (rc)
+ break;
+ }
+ spin_unlock(&s390_domain->list_lock);
+ spin_unlock_irqrestore(&s390_domain->dma_table_lock, irq_flags);
+
+ return rc;
+}
+
+static int s390_iommu_map(struct iommu_domain *domain, unsigned long iova,
+ phys_addr_t paddr, size_t size, int prot)
+{
+ struct s390_domain *s390_domain = to_s390_domain(domain);
+ int flags = ZPCI_PTE_VALID, rc = 0;
+
+ if (!(prot & IOMMU_READ))
+ return -EINVAL;
+
+ if (!(prot & IOMMU_WRITE))
+ flags |= ZPCI_TABLE_PROTECTED;
+
+ rc = s390_iommu_update_trans(s390_domain, (unsigned long) paddr, iova,
+ size, flags);
+
+ return rc;
+}
+
+static phys_addr_t s390_iommu_iova_to_phys(struct iommu_domain *domain,
+ dma_addr_t iova)
+{
+ struct s390_domain *s390_domain = to_s390_domain(domain);
+ unsigned long *sto, *pto, *rto, flags;
+ unsigned int rtx, sx, px;
+ phys_addr_t phys = 0;
+
+ if (iova < domain->geometry.aperture_start ||
+ iova > domain->geometry.aperture_end)
+ return 0;
+
+ rtx = calc_rtx(iova);
+ sx = calc_sx(iova);
+ px = calc_px(iova);
+ rto = s390_domain->dma_table;
+
+ spin_lock_irqsave(&s390_domain->dma_table_lock, flags);
+ if (rto && reg_entry_isvalid(rto[rtx])) {
+ sto = get_rt_sto(rto[rtx]);
+ if (sto && reg_entry_isvalid(sto[sx])) {
+ pto = get_st_pto(sto[sx]);
+ if (pto && pt_entry_isvalid(pto[px]))
+ phys = pto[px] & ZPCI_PTE_ADDR_MASK;
+ }
+ }
+ spin_unlock_irqrestore(&s390_domain->dma_table_lock, flags);
+
+ return phys;
+}
+
+static size_t s390_iommu_unmap(struct iommu_domain *domain,
+ unsigned long iova, size_t size)
+{
+ struct s390_domain *s390_domain = to_s390_domain(domain);
+ int flags = ZPCI_PTE_INVALID;
+ phys_addr_t paddr;
+ int rc;
+
+ paddr = s390_iommu_iova_to_phys(domain, iova);
+ if (!paddr)
+ return 0;
+
+ rc = s390_iommu_update_trans(s390_domain, (unsigned long) paddr, iova,
+ size, flags);
+ if (rc)
+ return 0;
+
+ return size;
+}
+
+static struct iommu_ops s390_iommu_ops = {
+ .capable = s390_iommu_capable,
+ .domain_alloc = s390_domain_alloc,
+ .domain_free = s390_domain_free,
+ .attach_dev = s390_iommu_attach_device,
+ .detach_dev = s390_iommu_detach_device,
+ .map = s390_iommu_map,
+ .unmap = s390_iommu_unmap,
+ .iova_to_phys = s390_iommu_iova_to_phys,
+ .add_device = s390_iommu_add_device,
+ .remove_device = s390_iommu_remove_device,
+ .pgsize_bitmap = S390_IOMMU_PGSIZES,
+};
+
+static int __init s390_iommu_init(void)
+{
+ return bus_set_iommu(&pci_bus_type, &s390_iommu_ops);
+}
+subsys_initcall(s390_iommu_init);