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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: D06DF1A0005 X-Stat-Signature: 61g65bax6tqotubnqqfcza9g97abd5z9 X-HE-Tag: 1749711315-561495 X-HE-Meta: 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 nlbs3Vt3 kFnN6CmGVqOvwOT+IVoFCSFRmiekGxXwBT7vH9Pjt+7a5NQrpUHsvxk5W1Rt6F7hx0xaYgpVD+RDJUlykqS6qneqZgzA6woriHvDmT7D05wr4cStMeC5SjhF6p329KFcwDoHi X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 12.06.25 03:56, Alistair Popple wrote: > On Wed, Jun 11, 2025 at 02:06:52PM +0200, David Hildenbrand wrote: >> 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. >> >> Identified by code inspection. >> >> Fixes: 7b806d229ef1 ("mm: remove vmf_insert_pfn_xxx_prot() for huge page-table entries") >> Cc: >> Signed-off-by: David Hildenbrand >> --- >> 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); > > Actually It's not immediately obvious to me why we don't call track_pfn_insert() > and forward the pgprot here as well. (track_pfn_insert is now called pfnmap_setup_cachemode_pfn) Prior to me adding vmf_insert_folio_pud() > device DAX would call vmf_insert_pfn_pud(), and the intent at least seems to > have been to change pgprot for that (and we did for the PTE/PMD versions). It's only for PFNMAP mappings as far as I understand. I think this is mostly about drivers mapping actual weird stuff with weird memory types (e.g., vfio mapping mmio etc) into the page tables, that does not have a struct page. > > However now that the ZONE_DEVICE folios are refcounted normally I switched > device dax to using vmf_insert_folio_*() which never changes pgprot based on x86 > PAT. So I think we probably need to either add that to vmf_insert_folio_*() or > a new variant or make it the responsibility of callers to figure out the correct > pgprot. I would assume that for ZONE_DEVICE the cachemode is always simpler (e.g., no MMIO?)? In any case, I would assume ZONE_DEVICE only ended up "accidentally" triggering it and that it didn't make a difference. Observe that pfnmap_setup_cachemode_pfn() is only called from vmf_insert_pfn_*() ... well, and our ugly friend __vm_insert_mixed() that similarly inserts a PFN mapping. -- Cheers, David / dhildenb