The patch titled
Subject: mm/access_process_vm: use the new follow_pfnmap API
has been added to the -mm mm-unstable branch. Its filename is
mm-access_process_vm-use-the-new-follow_pfnmap-api.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-access_process_vm-use-the-new-follow_pfnmap-api.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Peter Xu <peterx@xxxxxxxxxx>
Subject: mm/access_process_vm: use the new follow_pfnmap API
Date: Mon, 26 Aug 2024 16:43:49 -0400
Use the new API that can understand huge pfn mappings.
Link: https://lkml.kernel.org/r/20240826204353.2228736-16-peterx@xxxxxxxxxx
Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
Cc: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
Cc: Alex Williamson <alex.williamson@xxxxxxxxxx>
Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Christian Borntraeger <borntraeger@xxxxxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Gavin Shan <gshan@xxxxxxxxxx>
Cc: Gerald Schaefer <gerald.schaefer@xxxxxxxxxxxxx>
Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Niklas Schnelle <schnelle@xxxxxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Ryan Roberts <ryan.roberts@xxxxxxx>
Cc: Sean Christopherson <seanjc@xxxxxxxxxx>
Cc: Sven Schnelle <svens@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Zi Yan <ziy@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory.c | 28 ++++++++++++++--------------
1 file changed, 14 insertions(+), 14 deletions(-)
--- a/mm/memory.c~mm-access_process_vm-use-the-new-follow_pfnmap-api
+++ a/mm/memory.c
@@ -6538,34 +6538,34 @@ int generic_access_phys(struct vm_area_s
resource_size_t phys_addr;
unsigned long prot = 0;
void __iomem *maddr;
- pte_t *ptep, pte;
- spinlock_t *ptl;
int offset = offset_in_page(addr);
int ret = -EINVAL;
+ bool writable;
+ struct follow_pfnmap_args args = { .vma = vma, .address = addr };
retry:
- if (follow_pte(vma, addr, &ptep, &ptl))
+ if (follow_pfnmap_start(&args))
return -EINVAL;
- pte = ptep_get(ptep);
- pte_unmap_unlock(ptep, ptl);
+ prot = pgprot_val(args.pgprot);
+ phys_addr = (resource_size_t)args.pfn << PAGE_SHIFT;
+ writable = args.writable;
+ follow_pfnmap_end(&args);
- prot = pgprot_val(pte_pgprot(pte));
- phys_addr = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT;
-
- if ((write & FOLL_WRITE) && !pte_write(pte))
+ if ((write & FOLL_WRITE) && !writable)
return -EINVAL;
maddr = ioremap_prot(phys_addr, PAGE_ALIGN(len + offset), prot);
if (!maddr)
return -ENOMEM;
- if (follow_pte(vma, addr, &ptep, &ptl))
+ if (follow_pfnmap_start(&args))
goto out_unmap;
- if (!pte_same(pte, ptep_get(ptep))) {
- pte_unmap_unlock(ptep, ptl);
+ if ((prot != pgprot_val(args.pgprot)) ||
+ (phys_addr != (args.pfn << PAGE_SHIFT)) ||
+ (writable != args.writable)) {
+ follow_pfnmap_end(&args);
iounmap(maddr);
-
goto retry;
}
@@ -6574,7 +6574,7 @@ retry:
else
memcpy_fromio(buf, maddr + offset, len);
ret = len;
- pte_unmap_unlock(ptep, ptl);
+ follow_pfnmap_end(&args);
out_unmap:
iounmap(maddr);
_
Patches currently in -mm which might be from peterx@xxxxxxxxxx are
mm-dax-dump-start-address-in-fault-handler.patch
mm-mprotect-push-mmu-notifier-to-puds.patch
mm-powerpc-add-missing-pud-helpers.patch
mm-x86-make-pud_leaf-only-care-about-pse-bit.patch
mm-x86-implement-arch_check_zapped_pud.patch
mm-x86-add-missing-pud-helpers.patch
mm-mprotect-fix-dax-pud-handlings.patch
mm-introduce-arch_supports_huge_pfnmap-and-special-bits-to-pmd-pud.patch
mm-drop-is_huge_zero_pud.patch
mm-mark-special-bits-for-huge-pfn-mappings-when-inject.patch
mm-allow-thp-orders-for-pfnmaps.patch
mm-gup-detect-huge-pfnmap-entries-in-gup-fast.patch
mm-pagewalk-check-pfnmap-for-folio_walk_start.patch
mm-fork-accept-huge-pfnmap-entries.patch
mm-always-define-pxx_pgprot.patch
mm-new-follow_pfnmap-api.patch
kvm-use-follow_pfnmap-api.patch
s390-pci_mmio-use-follow_pfnmap-api.patch
mm-x86-pat-use-the-new-follow_pfnmap-api.patch
vfio-use-the-new-follow_pfnmap-api.patch
acrn-use-the-new-follow_pfnmap-api.patch
mm-access_process_vm-use-the-new-follow_pfnmap-api.patch
mm-remove-follow_pte.patch
mm-x86-support-large-pfn-mappings.patch
mm-arm64-support-large-pfn-mappings.patch
