6.8-stable review patch. If anyone has any objections, please let me know.
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From: Vasant Hegde vasant.hegde@amd.com
commit 0f91d0795741c12cee200667648669a91b568735 upstream.
Previously, IOMMU core layer was forcing IOMMU_DOMAIN_DMA domain for untrusted device. This always took precedence over driver's def_domain_type(). Commit 59ddce4418da ("iommu: Reorganize iommu_get_default_domain_type() to respect def_domain_type()") changed the behaviour. Current code calls def_domain_type() but if it doesn't return IOMMU_DOMAIN_DMA for untrusted device it throws error. This results in IOMMU group (and potentially IOMMU itself) in undetermined state.
This patch adds untrusted check in AMD IOMMU driver code. So that it allows eGPUs behind Thunderbolt work again.
Fine tuning amd_iommu_def_domain_type() will be done later.
Reported-by: Eric Wagner ewagner12@gmail.com Link: https://lore.kernel.org/linux-iommu/CAHudX3zLH6CsRmLE-yb+gRjhh-v4bU5_1jW_xCc... Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/3182 Fixes: 59ddce4418da ("iommu: Reorganize iommu_get_default_domain_type() to respect def_domain_type()") Cc: Robin Murphy robin.murphy@arm.com Cc: Jason Gunthorpe jgg@ziepe.ca Cc: stable@kernel.org # v6.7+ Signed-off-by: Vasant Hegde vasant.hegde@amd.com Link: https://lore.kernel.org/r/20240423111725.5813-1-vasant.hegde@amd.com Signed-off-by: Joerg Roedel jroedel@suse.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/iommu/amd/iommu.c | 4 ++++ 1 file changed, 4 insertions(+)
--- a/drivers/iommu/amd/iommu.c +++ b/drivers/iommu/amd/iommu.c @@ -2593,6 +2593,10 @@ static int amd_iommu_def_domain_type(str if (!dev_data) return 0;
+ /* Always use DMA domain for untrusted device */ + if (dev_is_pci(dev) && to_pci_dev(dev)->untrusted) + return IOMMU_DOMAIN_DMA; + /* * Do not identity map IOMMUv2 capable devices when: * - memory encryption is active, because some of those devices