search for: write_fault

When acting on device private mappings a driver needs to know if the device (or other entity in case of kvmppc) actually owns this private mapping. This series adds an owner field and converts the migrate_vma code over to check it. I looked into doing the same for hmm_range_fault, but as far as I can tell that code has never been wired up to actually work for device private memory, so instead of

...fns & range->flags[HMM_PFN_VALID])) return; - /* If this is device memory then only fault if explicitly requested */ - if ((cpu_flags & range->flags[HMM_PFN_DEVICE_PRIVATE])) { - /* Do we fault on device memory ? */ - if (pfns & range->flags[HMM_PFN_DEVICE_PRIVATE]) { - *write_fault = pfns & range->flags[HMM_PFN_WRITE]; - *fault = true; - } - return; - } /* If CPU page table is not valid then we need to fault */ *fault = !(cpu_flags & range->flags[HMM_PFN_VALID]); @@ -259,25 +250,6 @@ static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long add...

...a range lacking valid pmd or pte(s) - * @start: range virtual start address (inclusive) + * hmm_vma_walk_hole_() - handle a range lacking valid pmd or pte(s) + * @addr: range virtual start address (inclusive) * @end: range virtual end address (exclusive) * @fault: should we fault or not ? * @write_fault: write fault ? @@ -376,9 +376,9 @@ static inline void hmm_pte_need_fault(const struct hmm_vma_walk *hmm_vma_walk, /* * So we not only consider the individual per page request we also * consider the default flags requested for the range. The API can - * be use in 2 fashions. The first one w...

...FN_VALID])) > return; > - /* If this is device memory then only fault if explicitly requested */ > - if ((cpu_flags & range->flags[HMM_PFN_DEVICE_PRIVATE])) { > - /* Do we fault on device memory ? */ > - if (pfns & range->flags[HMM_PFN_DEVICE_PRIVATE]) { > - *write_fault = pfns & range->flags[HMM_PFN_WRITE]; > - *fault = true; > - } > - return; > - } > > /* If CPU page table is not valid then we need to fault */ > *fault = !(cpu_flags & range->flags[HMM_PFN_VALID]); > @@ -259,25 +250,6 @@ static int hmm_vma_handle_...

...--git a/mm/hmm.c b/mm/hmm.c > index 29371485fe94..4882b83aeccb 100644 > +++ b/mm/hmm.c > @@ -292,6 +292,9 @@ static int hmm_vma_walk_hole_(unsigned long addr, unsigned long end, > hmm_vma_walk->last = addr; > i = (addr - range->start) >> PAGE_SHIFT; > > + if (write_fault && walk->vma && !(walk->vma->vm_flags & VM_WRITE)) > + return -EPERM; Can walk->vma be NULL here? hmm_vma_do_fault() touches it unconditionally. Jason

I have been working on converting Jerome's hmm_dummy driver and self tests into a stand-alone set of tests to be included in tools/testing/selftests/vm and came across these two bug fixes in the process. The tests aren't quite ready to be posted as a patch. I'm posting the fixes now since I thought they shouldn't wait. They should probably have a fixes line but with all the HMM

...fns & range->flags[HMM_PFN_VALID])) return; - /* If this is device memory then only fault if explicitly requested */ - if ((cpu_flags & range->flags[HMM_PFN_DEVICE_PRIVATE])) { - /* Do we fault on device memory ? */ - if (pfns & range->flags[HMM_PFN_DEVICE_PRIVATE]) { - *write_fault = pfns & range->flags[HMM_PFN_WRITE]; - *fault = true; - } - return; - } /* If CPU page table is not valid then we need to fault */ *fault = !(cpu_flags & range->flags[HMM_PFN_VALID]); @@ -260,21 +251,15 @@ static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long ad...

...nt hmm_vma_handle_pmd(struct mm_walk *walk, > #ifdef CONFIG_TRANSPARENT_HUGEPAGE > struct hmm_vma_walk *hmm_vma_walk = walk->private; > struct hmm_range *range = hmm_vma_walk->range; > + struct dev_pagemap *pgmap = NULL; > unsigned long pfn, npages, i; > bool fault, write_fault; > uint64_t cpu_flags; > @@ -490,17 +490,14 @@ static int hmm_vma_handle_pmd(struct mm_walk *walk, > pfn = pmd_pfn(pmd) + pte_index(addr); > for (i = 0; addr < end; addr += PAGE_SIZE, i++, pfn++) { > if (pmd_devmap(pmd)) { > - hmm_vma_walk->pgmap = get_dev_pagemap...

...t;hch at lst.de> --- mm/hmm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/hmm.c b/mm/hmm.c index 03d37e102e3b..2083e4db46f5 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -486,7 +486,7 @@ static int hmm_vma_handle_pmd(struct mm_walk *walk, if (pmd_protnone(pmd) || fault || write_fault) return hmm_vma_walk_hole_(addr, end, fault, write_fault, walk); - pfn = pmd_pfn(pmd) + pte_index(addr); + pfn = pmd_pfn(pmd) + ((addr & ~PMD_MASK) >> PAGE_SHIFT); for (i = 0; addr < end; addr += PAGE_SIZE, i++, pfn++) { if (pmd_devmap(pmd)) { pgmap = get_dev_pagemap(pfn,...

...insertions(+) diff --git a/mm/hmm.c b/mm/hmm.c index 29371485fe94..4882b83aeccb 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -292,6 +292,9 @@ static int hmm_vma_walk_hole_(unsigned long addr, unsigned long end, hmm_vma_walk->last = addr; i = (addr - range->start) >> PAGE_SHIFT; + if (write_fault && walk->vma && !(walk->vma->vm_flags & VM_WRITE)) + return -EPERM; + for (; addr < end; addr += PAGE_SIZE, i++) { pfns[i] = range->values[HMM_PFN_NONE]; if (fault || write_fault) { -- 2.20.1

...private_entry_to_pfn(entry), + hmm_vma_walk->pgmap); + if (!unlikely(!pgmap)) + return -EBUSY; + if (hmm_vma_walk->pgmap->owner != + hmm_vma_walk->dev_private_owner) + cpu_flags = 0; + hmm_pte_need_fault(hmm_vma_walk, orig_pfn, cpu_flags, &fault, &write_fault); if (fault || write_fault) Jason

...FN_VALID])) > return; > - /* If this is device memory then only fault if explicitly requested */ > - if ((cpu_flags & range->flags[HMM_PFN_DEVICE_PRIVATE])) { > - /* Do we fault on device memory ? */ > - if (pfns & range->flags[HMM_PFN_DEVICE_PRIVATE]) { > - *write_fault = pfns & range->flags[HMM_PFN_WRITE]; > - *fault = true; > - } > - return; > - } > > /* If CPU page table is not valid then we need to fault */ > *fault = !(cpu_flags & range->flags[HMM_PFN_VALID]); > @@ -260,21 +251,15 @@ static int hmm_vma_handle...

Here are seven more patches for things I found to clean up. This was based on top of Christoph's seven patches: "hmm_range_fault related fixes and legacy API removal v3". I assume this will go into Jason's tree since there will likely be more HMM changes in this cycle. Changes from v1 to v2: Added AMD GPU to hmm_update removal. Added 2 patches from Christoph. Added 2 patches as

On Tue, Mar 17, 2020 at 09:15:36AM -0300, Jason Gunthorpe wrote: > > Getting rid of HMM_PFN_DEVICE_PRIVATE seems reasonable to me since a driver can > > look at the struct page but what if a driver needs to fault in a page from > > another device's private memory? Should it call handle_mm_fault()? > > Isn't that what this series basically does? > > The

...; @@ -475,6 +474,7 @@ static int hmm_vma_handle_pmd(struct mm_walk *walk, #ifdef CONFIG_TRANSPARENT_HUGEPAGE struct hmm_vma_walk *hmm_vma_walk = walk->private; struct hmm_range *range = hmm_vma_walk->range; + struct dev_pagemap *pgmap = NULL; unsigned long pfn, npages, i; bool fault, write_fault; uint64_t cpu_flags; @@ -490,17 +490,14 @@ static int hmm_vma_handle_pmd(struct mm_walk *walk, pfn = pmd_pfn(pmd) + pte_index(addr); for (i = 0; addr < end; addr += PAGE_SIZE, i++, pfn++) { if (pmd_devmap(pmd)) { - hmm_vma_walk->pgmap = get_dev_pagemap(pfn, - hmm_vma_walk...

...gt; #ifdef CONFIG_TRANSPARENT_HUGEPAGE > > struct hmm_vma_walk *hmm_vma_walk = walk->private; > > struct hmm_range *range = hmm_vma_walk->range; > > + struct dev_pagemap *pgmap = NULL; > > unsigned long pfn, npages, i; > > bool fault, write_fault; > > uint64_t cpu_flags; > > @@ -490,17 +490,14 @@ static int hmm_vma_handle_pmd(struct mm_walk *walk, > > pfn = pmd_pfn(pmd) + pte_index(addr); > > for (i = 0; addr < end; addr += PAGE_SIZE, i++, pfn++) { > > if (pmd_devmap(pmd)) { &...

Hi Jérôme, Ben, Felix and Jason, below is a series against the hmm tree which cleans up various minor bits and allows HMM_MIRROR to be built on all architectures. Diffstat: 11 files changed, 94 insertions(+), 210 deletions(-) A git tree is also available at: git://git.infradead.org/users/hch/misc.git hmm-cleanups.2 Gitweb:

When acting on device private mappings a driver needs to know if the device (or other entity in case of kvmppc) actually owns this private mapping. This series adds an owner field and converts the migrate_vma code over to check it. I looked into doing the same for hmm_range_fault, but as far as I can tell that code has never been wired up to actually work for device private memory, so instead of

Hi Jérôme, Ben, Felxi and Jason, below is a series against the hmm tree which cleans up various minor bits and allows HMM_MIRROR to be built on all architectures. Diffstat: 7 files changed, 81 insertions(+), 171 deletions(-) A git tree is also available at: git://git.infradead.org/users/hch/misc.git hmm-cleanups Gitweb:

...The logic is backwards from what you'd think.. If you *set* HMM_PFN_DEVICE_PRIVATE then this triggers: hmm_pte_need_fault(): if ((cpu_flags & range->flags[HMM_PFN_DEVICE_PRIVATE])) { /* Do we fault on device memory ? */ if (pfns & range->flags[HMM_PFN_DEVICE_PRIVATE]) { *write_fault = pfns & range->flags[HMM_PFN_WRITE]; *fault = true; } return; } Ie if the cpu page is a DEVICE_PRIVATE and the caller sets HMM_PFN_DEVICE_PRIVATE in the input flags (pfns) then it always faults it and never sets HMM_PFN_DEVICE_PRIVATE in the output flags. So setting 0 enabled devi...