Enabled via the kernel command-line 'iommu.passthrough=1' option.
Introduce the concept of identity domains to s390-iommu, which relies on
phys_to_dma and dma_to_phys to offset identity mappings to the start of
the DMA aperture advertized by CLP.
Signed-off-by: Matthew Rosato <mjrosato@xxxxxxxxxxxxx>
---
arch/s390/pci/pci.c | 6 ++++--
drivers/iommu/s390-iommu.c | 42 +++++++++++++++++++++++++++++++++++---
2 files changed, 43 insertions(+), 5 deletions(-)
diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
index 88f72745fa59..758b23331754 100644
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -124,14 +124,16 @@ int zpci_register_ioat(struct zpci_dev *zdev, u8 dmaas,
struct zpci_fib fib = {0};
u8 cc;
- WARN_ON_ONCE(iota & 0x3fff);
fib.pba = base;
/* Work around off by one in ISM virt device */
if (zdev->pft == PCI_FUNC_TYPE_ISM && limit > base)
fib.pal = limit + (1 << 12);
else
fib.pal = limit;
- fib.iota = iota | ZPCI_IOTA_RTTO_FLAG;
+ if (iota == 0)
+ fib.iota = iota;
+ else
+ fib.iota = iota | ZPCI_IOTA_RTTO_FLAG;
fib.gd = zdev->gisa;
cc = zpci_mod_fc(req, &fib, status);
if (cc)
diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c
index fbdeded3d48b..18979d8109b2 100644
--- a/drivers/iommu/s390-iommu.c
+++ b/drivers/iommu/s390-iommu.c
@@ -392,9 +392,11 @@ static int blocking_domain_attach_device(struct iommu_domain *domain,
return 0;
s390_domain = to_s390_domain(zdev->s390_domain);
- spin_lock_irqsave(&s390_domain->list_lock, flags);
- list_del_rcu(&zdev->iommu_list);
- spin_unlock_irqrestore(&s390_domain->list_lock, flags);
+ if (zdev->dma_table) {
+ spin_lock_irqsave(&s390_domain->list_lock, flags);
+ list_del_rcu(&zdev->iommu_list);
+ spin_unlock_irqrestore(&s390_domain->list_lock, flags);
+ }
zpci_unregister_ioat(zdev, 0);
zdev->dma_table = NULL;
@@ -787,6 +789,39 @@ static int __init s390_iommu_init(void)
}
subsys_initcall(s390_iommu_init);
+static int s390_attach_dev_identity(struct iommu_domain *domain,
+ struct device *dev)
+{
+ struct zpci_dev *zdev = to_zpci_dev(dev);
+ u8 status;
+ int cc;
+
+ blocking_domain_attach_device(&blocking_domain, dev);
+
+ /* If we fail now DMA remains blocked via blocking domain */
+ cc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
+ 0, &status);
+ /*
+ * If the device is undergoing error recovery the reset code
+ * will re-establish the new domain.
+ */
+ if (cc && status != ZPCI_PCI_ST_FUNC_NOT_AVAIL)
+ return -EIO;
+
+ zdev_s390_domain_update(zdev, domain);
+
+ return 0;
+}
+
+static const struct iommu_domain_ops s390_identity_ops = {
+ .attach_dev = s390_attach_dev_identity,
+};
+
+static struct iommu_domain s390_identity_domain = {
+ .type = IOMMU_DOMAIN_IDENTITY,
+ .ops = &s390_identity_ops,
+};
+
static struct iommu_domain blocking_domain = {
.type = IOMMU_DOMAIN_BLOCKED,
.ops = &(const struct iommu_domain_ops) {
@@ -797,6 +832,7 @@ static struct iommu_domain blocking_domain = {
static const struct iommu_ops s390_iommu_ops = {
.blocked_domain = &blocking_domain,
.release_domain = &blocking_domain,
+ .identity_domain = &s390_identity_domain,
.capable = s390_iommu_capable,
.domain_alloc_paging = s390_domain_alloc_paging,
.probe_device = s390_iommu_probe_device,
--
2.47.0
