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Lu Baolu
ebe16d245a
[ Upstream commit57f55048e5] Dirty page tracking relies on the IOMMU atomically updating the dirty bit in the paging-structure entry. For this operation to succeed, the paging- structure memory must be coherent between the IOMMU and the CPU. In another word, if the iommu page walk is incoherent, dirty page tracking doesn't work. The Intel VT-d specification, Section 3.10 "Snoop Behavior" states: "Remapping hardware encountering the need to atomically update A/EA/D bits in a paging-structure entry that is not snooped will result in a non- recoverable fault." To prevent an IOMMU from being incorrectly configured for dirty page tracking when it is operating in an incoherent mode, mark SSADS as supported only when both ecap_slads and ecap_smpwc are supported. Fixes:f35f22cc76("iommu/vt-d: Access/Dirty bit support for SS domains") Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/20250924083447.123224-1-baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> Signed-off-by: Sasha Levin <sashal@kernel.org>