From: Jacob Pan jacob.jun.pan@linux.intel.com
commit 194b3348bdbb7db65375c72f3f774aee4cc6614e upstream.
On platforms that do not support IOMMU Extended capability bit 0 Page-walk Coherency, CPU caches are not snooped when IOMMU is accessing any translation structures. IOMMU access goes only directly to memory. Intel IOMMU code was missing a flush for the PASID table directory that resulted in the unrecoverable fault as shown below.
This patch adds clflush calls whenever allocating and updating a PASID table directory to ensure cache coherency.
On the reverse direction, there's no need to clflush the PASID directory pointer when we deactivate a context entry in that IOMMU hardware will not see the old PASID directory pointer after we clear the context entry. PASID directory entries are also never freed once allocated.
DMAR: DRHD: handling fault status reg 3 DMAR: [DMA Read NO_PASID] Request device [00:0d.2] fault addr 0x1026a4000 [fault reason 0x51] SM: Present bit in Directory Entry is clear DMAR: Dump dmar1 table entries for IOVA 0x1026a4000 DMAR: scalable mode root entry: hi 0x0000000102448001, low 0x0000000101b3e001 DMAR: context entry: hi 0x0000000000000000, low 0x0000000101b4d401 DMAR: pasid dir entry: 0x0000000101b4e001 DMAR: pasid table entry[0]: 0x0000000000000109 DMAR: pasid table entry[1]: 0x0000000000000001 DMAR: pasid table entry[2]: 0x0000000000000000 DMAR: pasid table entry[3]: 0x0000000000000000 DMAR: pasid table entry[4]: 0x0000000000000000 DMAR: pasid table entry[5]: 0x0000000000000000 DMAR: pasid table entry[6]: 0x0000000000000000 DMAR: pasid table entry[7]: 0x0000000000000000 DMAR: PTE not present at level 4
Cc: stable@vger.kernel.org Fixes: 0bbeb01a4faf ("iommu/vt-d: Manage scalalble mode PASID tables") Reviewed-by: Kevin Tian kevin.tian@intel.com Reported-by: Sukumar Ghorai sukumar.ghorai@intel.com Signed-off-by: Ashok Raj ashok.raj@intel.com Signed-off-by: Jacob Pan jacob.jun.pan@linux.intel.com Link: https://lore.kernel.org/r/20230209212843.1788125-1-jacob.jun.pan@linux.intel... Signed-off-by: Lu Baolu 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/pasid.c | 7 +++++++ 1 file changed, 7 insertions(+)
--- a/drivers/iommu/intel/pasid.c +++ b/drivers/iommu/intel/pasid.c @@ -126,6 +126,9 @@ int intel_pasid_alloc_table(struct devic pasid_table->max_pasid = 1 << (order + PAGE_SHIFT + 3); info->pasid_table = pasid_table;
+ if (!ecap_coherent(info->iommu->ecap)) + clflush_cache_range(pasid_table->table, size); + return 0; }
@@ -213,6 +216,10 @@ retry: free_pgtable_page(entries); goto retry; } + if (!ecap_coherent(info->iommu->ecap)) { + clflush_cache_range(entries, VTD_PAGE_SIZE); + clflush_cache_range(&dir[dir_index].val, sizeof(*dir)); + } }
return &entries[index];