On Thu, 15 Jun 2017 15:11:52 +0200
Joerg Roedel <j...@8bytes.org> wrote:
> From: Joerg Roedel <jroe...@suse.de>
>
> Add support for the iommu_device_register interface to make
> the s390 hardware iommus visible to the iommu core and in
> sysfs.
>
> Signed-off-by: Joerg Roedel <jroe...@suse.de>
> ---
> arch/s390/include/asm/pci.h | 7 +++++++
> arch/s390/pci/pci.c | 5 +++++
> drivers/iommu/s390-iommu.c | 35 +++++++++++++++++++++++++++++++++++
> 3 files changed, 47 insertions(+)
>
> diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h
> index 4e31866..a3f697e 100644
> --- a/arch/s390/include/asm/pci.h
> +++ b/arch/s390/include/asm/pci.h
> @@ -8,6 +8,7 @@
>
> #include <linux/pci.h>
> #include <linux/mutex.h>
> +#include <linux/iommu.h>
> #include <asm-generic/pci.h>
> #include <asm/pci_clp.h>
> #include <asm/pci_debug.h>
> @@ -123,6 +124,8 @@ struct zpci_dev {
> unsigned long iommu_pages;
> unsigned int next_bit;
>
> + struct iommu_device iommu_dev; /* IOMMU core handle */
> +
> char res_name[16];
> struct zpci_bar_struct bars[PCI_BAR_COUNT];
>
> @@ -173,6 +176,10 @@ int clp_add_pci_device(u32, u32, int);
> int clp_enable_fh(struct zpci_dev *, u8);
> int clp_disable_fh(struct zpci_dev *);
>
> +/* IOMMU Interface */
> +int zpci_init_iommu(struct zpci_dev *zdev);
> +void zpci_destroy_iommu(struct zpci_dev *zdev);
> +
> #ifdef CONFIG_PCI
> /* Error handling and recovery */
> void zpci_event_error(void *);
> diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
> index 8051df1..4c13da6 100644
> --- a/arch/s390/pci/pci.c
> +++ b/arch/s390/pci/pci.c
> @@ -749,6 +749,7 @@ void pcibios_remove_bus(struct pci_bus *bus)
>
> zpci_exit_slot(zdev);
> zpci_cleanup_bus_resources(zdev);
> + zpci_destroy_iommu(zdev);
> zpci_free_domain(zdev);
>
> spin_lock(&zpci_list_lock);
> @@ -820,6 +821,10 @@ int zpci_create_device(struct zpci_dev *zdev)
> if (rc)
> goto out;
>
> + rc = zpci_init_iommu(zdev);
> + if (rc)
> + goto out_free;
> +
After this point, there are two options for failure (zpci_enable_device +
zpci_scan_bus), but missing error handling with an appropriate call to
zpci_destroy_iommu().
I must admit that I do not understand what these sysfs attributes are
used for, and by whom and when. Is it really necessary/correct to register
them (including the s390_iommu_ops) _before_ the zpci_dev is registered
to the bus (zpci_scan_bus -> pci_scan_root_bus/pci_bus_add_devices)?
What is the expected life cycle for the attributes, and are they already
needed when a device is still under DMA API access, or even before it is
added to the PCI bus?
> mutex_init(&zdev->lock);
> if (zdev->state == ZPCI_FN_STATE_CONFIGURED) {
> rc = zpci_enable_device(zdev);
> diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c
> index 8788640..85f3bc5 100644
> --- a/drivers/iommu/s390-iommu.c
> +++ b/drivers/iommu/s390-iommu.c
> @@ -18,6 +18,8 @@
> */
> #define S390_IOMMU_PGSIZES (~0xFFFUL)
>
> +static struct iommu_ops s390_iommu_ops;
> +
> struct s390_domain {
> struct iommu_domain domain;
> struct list_head devices;
> @@ -166,11 +168,13 @@ static void s390_iommu_detach_device(struct
> iommu_domain *domain,
> static int s390_iommu_add_device(struct device *dev)
> {
> struct iommu_group *group = iommu_group_get_for_dev(dev);
> + struct zpci_dev *zdev = to_pci_dev(dev)->sysdata;
>
> if (IS_ERR(group))
> return PTR_ERR(group);
>
> iommu_group_put(group);
> + iommu_device_link(&zdev->iommu_dev, dev);
>
> return 0;
> }
> @@ -197,6 +201,7 @@ static void s390_iommu_remove_device(struct device *dev)
> s390_iommu_detach_device(domain, dev);
> }
>
> + iommu_device_unlink(&zdev->iommu_dev, dev);
> iommu_group_remove_device(dev);
> }
>
> @@ -327,6 +332,36 @@ static size_t s390_iommu_unmap(struct iommu_domain
> *domain,
> return size;
> }
>
> +int zpci_init_iommu(struct zpci_dev *zdev)
> +{
> + int rc = 0;
> +
> + rc = iommu_device_sysfs_add(&zdev->iommu_dev, NULL, NULL,
> + "s390-iommu.%08x", zdev->fid);
> + if (rc)
> + goto out_err;
> +
> + iommu_device_set_ops(&zdev->iommu_dev, &s390_iommu_ops);
> +
> + rc = iommu_device_register(&zdev->iommu_dev);
> + if (rc)
> + goto out_sysfs;
> +
> + return 0;
> +
> +out_sysfs:
> + iommu_device_sysfs_remove(&zdev->iommu_dev);
> +
> +out_err:
> + return rc;
> +}
> +
> +void zpci_destroy_iommu(struct zpci_dev *zdev)
> +{
> + iommu_device_unregister(&zdev->iommu_dev);
> + iommu_device_sysfs_remove(&zdev->iommu_dev);
> +}
> +
> static struct iommu_ops s390_iommu_ops = {
> .capable = s390_iommu_capable,
> .domain_alloc = s390_domain_alloc,
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