[PATCH v5 3/4] iommu/s390: handle IOAT registration based on domain

Matthew Rosato
2025-02-12T21:34:38Z

At this point, the dma_table is really a property of the s390-iommu
domain. Rather than checking its contents elsewhere in the codebase,
move the code that registers the table with firmware into
s390-iommu and make a decision what to register with firmware based
upon the type of domain in use for the device in question.

Tested-by: Niklas Schnelle <schnelle@linux.ibm.com>
Reviewed-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
---
arch/s390/include/asm/pci.h | 2 ++
arch/s390/kvm/pci.c | 17 ++-------------
arch/s390/pci/pci.c | 35 +++++++++++++++++-------------
arch/s390/pci/pci_sysfs.c | 11 +---------
drivers/iommu/s390-iommu.c | 43 +++++++++++++++++++++++++++++++++++--
5 files changed, 66 insertions(+), 42 deletions(-)

diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h
index 8fe4c7a72c0b..7cc6a7cc66e7 100644
--- a/arch/s390/include/asm/pci.h
+++ b/arch/s390/include/asm/pci.h
@@ -217,6 +217,7 @@ extern struct airq_iv *zpci_aif_sbv;
struct zpci_dev *zpci_create_device(u32 fid, u32 fh, enum zpci_state state);
int zpci_add_device(struct zpci_dev *zdev);
int zpci_enable_device(struct zpci_dev *);
+int zpci_reenable_device(struct zpci_dev *zdev);
int zpci_disable_device(struct zpci_dev *);
int zpci_scan_configured_device(struct zpci_dev *zdev, u32 fh);
int zpci_deconfigure_device(struct zpci_dev *zdev);
@@ -245,6 +246,7 @@ void update_uid_checking(bool new);
/* IOMMU Interface */
int zpci_init_iommu(struct zpci_dev *zdev);
void zpci_destroy_iommu(struct zpci_dev *zdev);
+int zpci_iommu_register_ioat(struct zpci_dev *zdev, u8 *status);

#ifdef CONFIG_PCI
static inline bool zpci_use_mio(struct zpci_dev *zdev)
diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c
index 9b9e7fdd5380..8c40154ff50f 100644
--- a/arch/s390/kvm/pci.c
+++ b/arch/s390/kvm/pci.c
@@ -433,7 +433,6 @@ static void kvm_s390_pci_dev_release(struct zpci_dev *zdev)
static int kvm_s390_pci_register_kvm(void *opaque, struct kvm *kvm)
{
struct zpci_dev *zdev = opaque;
- u8 status;
int rc;

if (!zdev)
@@ -480,13 +479,7 @@ static int kvm_s390_pci_register_kvm(void *opaque, struct kvm *kvm)
*/
zdev->gisa = (u32)virt_to_phys(&kvm->arch.sie_page2->gisa);

- rc = zpci_enable_device(zdev);
- if (rc)
- goto clear_gisa;
-
- /* Re-register the IOMMU that was already created */
- rc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
- virt_to_phys(zdev->dma_table), &status);
+ rc = zpci_reenable_device(zdev);
if (rc)
goto clear_gisa;

@@ -516,7 +509,6 @@ static void kvm_s390_pci_unregister_kvm(void *opaque)
{
struct zpci_dev *zdev = opaque;
struct kvm *kvm;
- u8 status;

if (!zdev)
return;
@@ -550,12 +542,7 @@ static void kvm_s390_pci_unregister_kvm(void *opaque)
goto out;
}

- if (zpci_enable_device(zdev))
- goto out;
-
- /* Re-register the IOMMU that was already created */
- zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
- virt_to_phys(zdev->dma_table), &status);
+ zpci_reenable_device(zdev);

out:
spin_lock(&kvm->arch.kzdev_list_lock);
diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
index 88f72745fa59..fa879351efb5 100644
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -124,14 +124,13 @@ 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;
+ fib.iota = iota;
fib.gd = zdev->gisa;
cc = zpci_mod_fc(req, &fib, status);
if (cc)
@@ -690,6 +689,23 @@ int zpci_enable_device(struct zpci_dev *zdev)
}
EXPORT_SYMBOL_GPL(zpci_enable_device);

+int zpci_reenable_device(struct zpci_dev *zdev)
+{
+ u8 status;
+ int rc;
+
+ rc = zpci_enable_device(zdev);
+ if (rc)
+ return rc;
+
+ rc = zpci_iommu_register_ioat(zdev, &status);
+ if (rc)
+ zpci_disable_device(zdev);
+
+ return rc;
+}
+EXPORT_SYMBOL_GPL(zpci_reenable_device);
+
int zpci_disable_device(struct zpci_dev *zdev)
{
u32 fh = zdev->fh;
@@ -739,7 +755,6 @@ EXPORT_SYMBOL_GPL(zpci_disable_device);
*/
int zpci_hot_reset_device(struct zpci_dev *zdev)
{
- u8 status;
int rc;

lockdep_assert_held(&zdev->state_lock);
@@ -758,19 +773,9 @@ int zpci_hot_reset_device(struct zpci_dev *zdev)
return rc;
}

- rc = zpci_enable_device(zdev);
- if (rc)
- return rc;
-
- if (zdev->dma_table)
- rc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
- virt_to_phys(zdev->dma_table), &status);
- if (rc) {
- zpci_disable_device(zdev);
- return rc;
- }
+ rc = zpci_reenable_device(zdev);

- return 0;
+ return rc;
}

/**
diff --git a/arch/s390/pci/pci_sysfs.c b/arch/s390/pci/pci_sysfs.c
index 2de1ea6c3a8c..0ecad08e1b1e 100644
--- a/arch/s390/pci/pci_sysfs.c
+++ b/arch/s390/pci/pci_sysfs.c
@@ -52,7 +52,6 @@ static DEVICE_ATTR_RO(mio_enabled);

static int _do_recover(struct pci_dev *pdev, struct zpci_dev *zdev)
{
- u8 status;
int ret;

pci_stop_and_remove_bus_device(pdev);
@@ -70,16 +69,8 @@ static int _do_recover(struct pci_dev *pdev, struct zpci_dev *zdev)
return ret;
}

- ret = zpci_enable_device(zdev);
- if (ret)
- return ret;
+ ret = zpci_reenable_device(zdev);

- if (zdev->dma_table) {
- ret = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
- virt_to_phys(zdev->dma_table), &status);
- if (ret)
- zpci_disable_device(zdev);
- }
return ret;
}

diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c
index fbdeded3d48b..007ccfdad495 100644
--- a/drivers/iommu/s390-iommu.c
+++ b/drivers/iommu/s390-iommu.c
@@ -381,6 +381,46 @@ static void zdev_s390_domain_update(struct zpci_dev *zdev,
spin_unlock_irqrestore(&zdev->dom_lock, flags);
}

+static int s390_iommu_domain_reg_ioat(struct zpci_dev *zdev,
+ struct iommu_domain *domain, u8 *status)
+{
+ struct s390_domain *s390_domain;
+ int rc = 0;
+ u64 iota;
+
+ switch (domain->type) {
+ case IOMMU_DOMAIN_IDENTITY:
+ rc = zpci_register_ioat(zdev, 0, zdev->start_dma,
+ zdev->end_dma, 0, status);
+ break;
+ case IOMMU_DOMAIN_BLOCKED:
+ /* Nothing to do in this case */
+ break;
+ default:
+ s390_domain = to_s390_domain(domain);
+ iota = virt_to_phys(s390_domain->dma_table) |
+ ZPCI_IOTA_RTTO_FLAG;
+ rc = zpci_register_ioat(zdev, 0, zdev->start_dma,
+ zdev->end_dma, iota, status);
+ }
+
+ return rc;
+}
+
+int zpci_iommu_register_ioat(struct zpci_dev *zdev, u8 *status)
+{
+ unsigned long flags;
+ int rc;
+
+ spin_lock_irqsave(&zdev->dom_lock, flags);
+
+ rc = s390_iommu_domain_reg_ioat(zdev, zdev->s390_domain, status);
+
+ spin_unlock_irqrestore(&zdev->dom_lock, flags);
+
+ return rc;
+}
+
static int blocking_domain_attach_device(struct iommu_domain *domain,
struct device *dev)
{
@@ -422,8 +462,7 @@ static int s390_iommu_attach_device(struct iommu_domain *domain,
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,
- virt_to_phys(s390_domain->dma_table), &status);
+ cc = s390_iommu_domain_reg_ioat(zdev, domain, &status);
if (cc && status != ZPCI_PCI_ST_FUNC_NOT_AVAIL)
return -EIO;
zdev->dma_table = s390_domain->dma_table;
--
2.48.1