From: Matthew Rosato Date: Thu, 19 May 2022 14:29:29 -0400 Subject: iommu/s390: Tolerate repeat attach_dev calls Git-commit: fa7e9ecc5e1c1a1e8aa7014b2749b22edc801dd2 Patch-mainline: v5.19-rc1 References: bsc#1205701 Since commit 0286300e6045 ("iommu: iommu_group_claim_dma_owner() must always assign a domain") s390-iommu will get called to allocate multiple unmanaged iommu domains for a vfio-pci device -- however the current s390-iommu logic tolerates only one. Recognize that multiple domains can be allocated and handle switching between DMA or different iommu domain tables during attach_dev. Signed-off-by: Matthew Rosato Reviewed-by: Jason Gunthorpe Link: https://lore.kernel.org/r/20220519182929.581898-1-mjrosato@linux.ibm.com Signed-off-by: Joerg Roedel --- drivers/iommu/s390-iommu.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c index 3833e86c6e7b..c898bcbbce11 100644 --- a/drivers/iommu/s390-iommu.c +++ b/drivers/iommu/s390-iommu.c @@ -99,7 +99,7 @@ static int s390_iommu_attach_device(struct iommu_domain *domain, if (!domain_device) return -ENOMEM; - if (zdev->dma_table) { + if (zdev->dma_table && !zdev->s390_domain) { cc = zpci_dma_exit_device(zdev); if (cc) { rc = -EIO; @@ -107,6 +107,9 @@ static int s390_iommu_attach_device(struct iommu_domain *domain, } } + if (zdev->s390_domain) + zpci_unregister_ioat(zdev, 0); + zdev->dma_table = s390_domain->dma_table; cc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma, virt_to_phys(zdev->dma_table)); @@ -136,7 +139,13 @@ static int s390_iommu_attach_device(struct iommu_domain *domain, return 0; out_restore: - zpci_dma_init_device(zdev); + if (!zdev->s390_domain) { + zpci_dma_init_device(zdev); + } else { + zdev->dma_table = zdev->s390_domain->dma_table; + zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma, + virt_to_phys(zdev->dma_table)); + } out_free: kfree(domain_device); @@ -167,7 +176,7 @@ static void s390_iommu_detach_device(struct iommu_domain *domain, } spin_unlock_irqrestore(&s390_domain->list_lock, flags); - if (found) { + if (found && (zdev->s390_domain == s390_domain)) { zdev->s390_domain = NULL; zpci_unregister_ioat(zdev, 0); zpci_dma_init_device(zdev);