From: Tina Zhang tina.zhang@intel.com
commit 242b0aaeabbe2efbef1b9d42a8e56627e800964c upstream.
The A/D bits are preseted for IOVA over first level(FL) usage for both kernel DMA (i.e, domain typs is IOMMU_DOMAIN_DMA) and user space DMA usage (i.e., domain type is IOMMU_DOMAIN_UNMANAGED).
Presetting A bit in FL requires to preset the bit in every related paging entries, including the non-leaf ones. Otherwise, hardware may treat this as an error. For example, in a case of ECAP_REG.SMPWC==0, DMA faults might occur with below DMAR fault messages (wrapped for line length) dumped.
DMAR: DRHD: handling fault status reg 2 DMAR: [DMA Read NO_PASID] Request device [aa:00.0] fault addr 0x10c3a6000 [fault reason 0x90] SM: A/D bit update needed in first-level entry when set up in no snoop
Fixes: 289b3b005cb9 ("iommu/vt-d: Preset A/D bits for user space DMA usage") Cc: stable@vger.kernel.org Signed-off-by: Tina Zhang tina.zhang@intel.com Link: https://lore.kernel.org/r/20221113010324.1094483-1-tina.zhang@intel.com Signed-off-by: Lu Baolu baolu.lu@linux.intel.com Link: https://lore.kernel.org/r/20221116051544.26540-2-baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel jroedel@suse.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/iommu/intel/iommu.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-)
--- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -954,11 +954,9 @@ static struct dma_pte *pfn_to_dma_pte(st
domain_flush_cache(domain, tmp_page, VTD_PAGE_SIZE); pteval = ((uint64_t)virt_to_dma_pfn(tmp_page) << VTD_PAGE_SHIFT) | DMA_PTE_READ | DMA_PTE_WRITE; - if (domain_use_first_level(domain)) { - pteval |= DMA_FL_PTE_XD | DMA_FL_PTE_US; - if (iommu_is_dma_domain(&domain->domain)) - pteval |= DMA_FL_PTE_ACCESS; - } + if (domain_use_first_level(domain)) + pteval |= DMA_FL_PTE_XD | DMA_FL_PTE_US | DMA_FL_PTE_ACCESS; + if (cmpxchg64(&pte->val, 0ULL, pteval)) /* Someone else set it while we were thinking; use theirs. */ free_pgtable_page(tmp_page);