From 1000dccd5d134951d5fd37a7ad85ad7b19b825fc Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Thu, 11 May 2023 01:42:13 -0300 Subject: [PATCH] iommu: Allow IOMMU_RESV_DIRECT to work on ARM For now several ARM drivers do not allow mappings to be created until a domain is attached. This means they do not technically support IOMMU_RESV_DIRECT as it requires the 1:1 maps to work continuously. Currently if the platform requests these maps on ARM systems they are silently ignored. Work around this by trying again to establish the direct mappings after the domain is attached if the pre-attach attempt failed. In the long run the drivers will be fixed to fully setup domains when they are created without waiting for attachment. Reviewed-by: Lu Baolu Reviewed-by: Kevin Tian Tested-by: Heiko Stuebner Tested-by: Niklas Schnelle Signed-off-by: Jason Gunthorpe Link: https://lore.kernel.org/r/15-v5-1b99ae392328+44574-iommu_err_unwind_jgg@nvidia.com Signed-off-by: Joerg Roedel --- drivers/iommu/iommu.c | 33 +++++++++++++++++++++++++++++++-- 1 file changed, 31 insertions(+), 2 deletions(-) diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 34f721434b28..197d46a1d068 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -2842,6 +2842,7 @@ static int iommu_setup_default_domain(struct iommu_group *group, struct iommu_domain *old_dom = group->default_domain; struct group_device *gdev; struct iommu_domain *dom; + bool direct_failed; int req_type; int ret; @@ -2875,8 +2876,15 @@ static int iommu_setup_default_domain(struct iommu_group *group, * mapped before their device is attached, in order to guarantee * continuity with any FW activity */ - for_each_group_device(group, gdev) - iommu_create_device_direct_mappings(dom, gdev->dev); + direct_failed = false; + for_each_group_device(group, gdev) { + if (iommu_create_device_direct_mappings(dom, gdev->dev)) { + direct_failed = true; + dev_warn_once( + gdev->dev->iommu->iommu_dev->dev, + "IOMMU driver was not able to establish FW requested direct mapping."); + } + } /* We must set default_domain early for __iommu_device_set_domain */ group->default_domain = dom; @@ -2900,6 +2908,27 @@ static int iommu_setup_default_domain(struct iommu_group *group, } } + /* + * Drivers are supposed to allow mappings to be installed in a domain + * before device attachment, but some don't. Hack around this defect by + * trying again after attaching. If this happens it means the device + * will not continuously have the IOMMU_RESV_DIRECT map. + */ + if (direct_failed) { + for_each_group_device(group, gdev) { + ret = iommu_create_device_direct_mappings(dom, gdev->dev); + if (ret) + goto err_restore; + } + } + +err_restore: + if (old_dom) { + __iommu_group_set_domain_internal( + group, old_dom, IOMMU_SET_DOMAIN_MUST_SUCCEED); + iommu_domain_free(dom); + old_dom = NULL; + } out_free: if (old_dom) iommu_domain_free(old_dom);