From 59bbf596791b89c7f88fdcac29dfc39c1221d25d Mon Sep 17 00:00:00 2001 From: Niklas Schnelle Date: Wed, 9 Nov 2022 15:28:59 +0100 Subject: iommu/s390: Make attach succeed even if the device is in error state If a zPCI device is in the error state while switching IOMMU domains zpci_register_ioat() will fail and we would end up with the device not attached to any domain. In this state since zdev->dma_table == NULL a reset via zpci_hot_reset_device() would wrongfully re-initialize the device for DMA API usage using zpci_dma_init_device(). As automatic recovery is currently disabled while attached to an IOMMU domain this only affects slot resets triggered through other means but will affect automatic recovery once we switch to using dma-iommu. Additionally with that switch common code expects attaching to the default domain to always work so zpci_register_ioat() should only fail if there is no chance to recover anyway, e.g. if the device has been unplugged. Improve the robustness of attach by specifically looking at the status returned by zpci_mod_fc() to determine if the device is unavailable and in this case simply ignore the error. Once the device is reset zpci_hot_reset_device() will then correctly set the domain's DMA translation tables. Signed-off-by: Niklas Schnelle Reviewed-by: Matthew Rosato Link: https://lore.kernel.org/r/20221109142903.4080275-2-schnelle@linux.ibm.com Signed-off-by: Joerg Roedel --- drivers/iommu/s390-iommu.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'drivers/iommu') diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c index 7fb512bece9a..e2c886bc4376 100644 --- a/drivers/iommu/s390-iommu.c +++ b/drivers/iommu/s390-iommu.c @@ -98,6 +98,7 @@ static int s390_iommu_attach_device(struct iommu_domain *domain, struct s390_domain *s390_domain = to_s390_domain(domain); struct zpci_dev *zdev = to_zpci_dev(dev); unsigned long flags; + u8 status; int cc; if (!zdev) @@ -113,8 +114,12 @@ static int s390_iommu_attach_device(struct iommu_domain *domain, zpci_dma_exit_device(zdev); cc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma, - virt_to_phys(s390_domain->dma_table)); - if (cc) + virt_to_phys(s390_domain->dma_table), &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->dma_table = s390_domain->dma_table; -- cgit v1.2.3