We setup the cache mode but ... don't forward the updated pgprot to insert_pfn_pud().

Only a problem on x86-64 PAT when mapping PFNs using PUDs that require a special cachemode.

Fix it by using the proper pgprot where the cachemode was setup.

It is unclear in which configurations we would get the cachemode wrong: through vfio seems possible. Getting cachemodes wrong is usually ... bad. As the fix is easy, let's backport it to stable.

Identified by code inspection.

Fixes: 7b806d229ef1 ("mm: remove vmf_insert_pfn_xxx_prot() for huge page-table entries") Reviewed-by: Dan Williams dan.j.williams@intel.com Reviewed-by: Lorenzo Stoakes lorenzo.stoakes@oracle.com Reviewed-by: Jason Gunthorpe jgg@nvidia.com Tested-by: Dan Williams dan.j.williams@intel.com Cc: stable@vger.kernel.org Signed-off-by: David Hildenbrand david@redhat.com --- mm/huge_memory.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c index d3e66136e41a3..49b98082c5401 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1516,10 +1516,9 @@ static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma) }

static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, - pud_t *pud, pfn_t pfn, bool write) + pud_t *pud, pfn_t pfn, pgprot_t prot, bool write) { struct mm_struct *mm = vma->vm_mm; - pgprot_t prot = vma->vm_page_prot; pud_t entry;

if (!pud_none(*pud)) { @@ -1581,7 +1580,7 @@ vm_fault_t vmf_insert_pfn_pud(struct vm_fault *vmf, pfn_t pfn, bool write) pfnmap_setup_cachemode_pfn(pfn_t_to_pfn(pfn), &pgprot);

ptl = pud_lock(vma->vm_mm, vmf->pud); - insert_pfn_pud(vma, addr, vmf->pud, pfn, write); + insert_pfn_pud(vma, addr, vmf->pud, pfn, pgprot, write); spin_unlock(ptl);

return VM_FAULT_NOPAGE; @@ -1625,7 +1624,7 @@ vm_fault_t vmf_insert_folio_pud(struct vm_fault *vmf, struct folio *folio, add_mm_counter(mm, mm_counter_file(folio), HPAGE_PUD_NR); } insert_pfn_pud(vma, addr, vmf->pud, pfn_to_pfn_t(folio_pfn(folio)), - write); + vma->vm_page_prot, write); spin_unlock(ptl);

return VM_FAULT_NOPAGE;