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Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Axel Rasmussen , Yuanchu Xie , Chunyan Zhang References: <20250911095602.1130290-1-zhangchunyan@iscas.ac.cn> <20250911095602.1130290-3-zhangchunyan@iscas.ac.cn> From: David Hildenbrand Autocrypt: addr=david@redhat.com; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZoEEwEIAEQCGwMCF4ACGQEFCwkIBwICIgIG FQoJCAsCBBYCAwECHgcWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaJzangUJJlgIpAAKCRBN 3hD3AP+DWhAxD/9wcL0A+2rtaAmutaKTfxhTP0b4AAp1r/eLxjrbfbCCmh4pqzBhmSX/4z11 opn2KqcOsueRF1t2ENLOWzQu3Roiny2HOU7DajqB4dm1BVMaXQya5ae2ghzlJN9SIoopTWlR 0Af3hPj5E2PYvQhlcqeoehKlBo9rROJv/rjmr2x0yOM8qeTroH/ZzNlCtJ56AsE6Tvl+r7cW 3x7/Jq5WvWeudKrhFh7/yQ7eRvHCjd9bBrZTlgAfiHmX9AnCCPRPpNGNedV9Yty2Jnxhfmbv Pw37LA/jef8zlCDyUh2KCU1xVEOWqg15o1RtTyGV1nXV2O/mfuQJud5vIgzBvHhypc3p6VZJ lEf8YmT+Ol5P7SfCs5/uGdWUYQEMqOlg6w9R4Pe8d+mk8KGvfE9/zTwGg0nRgKqlQXrWRERv cuEwQbridlPAoQHrFWtwpgYMXx2TaZ3sihcIPo9uU5eBs0rf4mOERY75SK+Ekayv2ucTfjxr Kf014py2aoRJHuvy85ee/zIyLmve5hngZTTe3Wg3TInT9UTFzTPhItam6dZ1xqdTGHZYGU0O otRHcwLGt470grdiob6PfVTXoHlBvkWRadMhSuG4RORCDpq89vu5QralFNIf3EysNohoFy2A LYg2/D53xbU/aa4DDzBb5b1Rkg/udO1gZocVQWrDh6I2K3+cCs7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: <20250911095602.1130290-3-zhangchunyan@iscas.ac.cn> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: bGPh0ggIiwVsYI67ynzVkioJdA45OkHgsKtcO63rKcQ_1757667262 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 2D04410000E X-Stat-Signature: odndiyp7kiujzex58aey3td9uoefaa6g X-Rspam-User: X-Rspamd-Server: rspam01 X-HE-Tag: 1757667266-579204 X-HE-Meta: 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 5tMSoTXw 6hKNKjfbxSVoBjcu2mjeS1Ihkakx1Y0vUGPGfxIPlZPZHLfVF/k6XhRJVmItzeICUFbYh1pAYOxwm410m7SlALm4CeoOE/0rAdHbT3pZLyWANvB6G2jRqKBNGYoKJXw+4VkSK+HNd6zOAs0Fxk8Yt7RsO06j/2NHXcxmVso9JsXwcZy48wO9ShLGukSCom+Nh72eB 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 11.09.25 11:55, Chunyan Zhang wrote: > Some platforms can customize the PTE/PMD entry uffd-wp bit making > it unavailable even if the architecture provides the resource. > This patch adds a macro API that allows architectures to define their > specific implementations to check if the uffd-wp bit is available > on which device the kernel is running. If you change the name of the sofdirty thingy, adjust that one here as well. > > Signed-off-by: Chunyan Zhang > --- > fs/userfaultfd.c | 23 ++++++++-------- > include/asm-generic/pgtable_uffd.h | 11 ++++++++ > include/linux/mm_inline.h | 7 +++++ > include/linux/userfaultfd_k.h | 44 +++++++++++++++++++----------- > mm/memory.c | 6 ++-- > 5 files changed, 62 insertions(+), 29 deletions(-) > > diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c > index 54c6cc7fe9c6..b549c327d7ad 100644 > --- a/fs/userfaultfd.c > +++ b/fs/userfaultfd.c > @@ -1270,9 +1270,9 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, > if (uffdio_register.mode & UFFDIO_REGISTER_MODE_MISSING) > vm_flags |= VM_UFFD_MISSING; > if (uffdio_register.mode & UFFDIO_REGISTER_MODE_WP) { > -#ifndef CONFIG_HAVE_ARCH_USERFAULTFD_WP > - goto out; > -#endif > + if (!pgtable_uffd_wp_supported()) > + goto out; > + > vm_flags |= VM_UFFD_WP; I like that, similar to the softdirty thing we will simply not set the flag. > } > if (uffdio_register.mode & UFFDIO_REGISTER_MODE_MINOR) { > @@ -1980,14 +1980,15 @@ static int userfaultfd_api(struct userfaultfd_ctx *ctx, > uffdio_api.features &= > ~(UFFD_FEATURE_MINOR_HUGETLBFS | UFFD_FEATURE_MINOR_SHMEM); > #endif > -#ifndef CONFIG_HAVE_ARCH_USERFAULTFD_WP > - uffdio_api.features &= ~UFFD_FEATURE_PAGEFAULT_FLAG_WP; > -#endif > -#ifndef CONFIG_PTE_MARKER_UFFD_WP > - uffdio_api.features &= ~UFFD_FEATURE_WP_HUGETLBFS_SHMEM; > - uffdio_api.features &= ~UFFD_FEATURE_WP_UNPOPULATED; > - uffdio_api.features &= ~UFFD_FEATURE_WP_ASYNC; > -#endif > + if (!pgtable_uffd_wp_supported()) > + uffdio_api.features &= ~UFFD_FEATURE_PAGEFAULT_FLAG_WP; > + > + if (!IS_ENABLED(CONFIG_PTE_MARKER_UFFD_WP) || > + !pgtable_uffd_wp_supported()) { I wonder if we would want to have a helper for that like static inline bool uffd_supports_wp_marker(void) { return pgtable_uffd_wp_supported() && IS_ENABLED(CONFIG_PTE_MARKER_UFFD_WP); } That should clean all of this futher up. > + uffdio_api.features &= ~UFFD_FEATURE_WP_HUGETLBFS_SHMEM; > + uffdio_api.features &= ~UFFD_FEATURE_WP_UNPOPULATED; > + uffdio_api.features &= ~UFFD_FEATURE_WP_ASYNC; > + } > > ret = -EINVAL; > if (features & ~uffdio_api.features) > diff --git a/include/asm-generic/pgtable_uffd.h b/include/asm-generic/pgtable_uffd.h > index 828966d4c281..895d68ece0e7 100644 > --- a/include/asm-generic/pgtable_uffd.h > +++ b/include/asm-generic/pgtable_uffd.h > @@ -1,6 +1,17 @@ > #ifndef _ASM_GENERIC_PGTABLE_UFFD_H > #define _ASM_GENERIC_PGTABLE_UFFD_H > > +/* > + * Some platforms can customize the uffd-wp bit, making it unavailable > + * even if the architecture provides the resource. > + * Adding this API allows architectures to add their own checks for the > + * devices on which the kernel is running. > + * Note: When overiding it, please make sure the s/overiding/overriding/ > + * CONFIG_HAVE_ARCH_USERFAULTFD_WP is part of this macro. > + */ > +#ifndef pgtable_uffd_wp_supported > +#define pgtable_uffd_wp_supported() IS_ENABLED(CONFIG_HAVE_ARCH_USERFAULTFD_WP) > +#endif > #ifndef CONFIG_HAVE_ARCH_USERFAULTFD_WP > static __always_inline int pte_uffd_wp(pte_t pte) > { > diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h > index 89b518ff097e..38845b8b79ff 100644 > --- a/include/linux/mm_inline.h > +++ b/include/linux/mm_inline.h > @@ -571,6 +571,13 @@ pte_install_uffd_wp_if_needed(struct vm_area_struct *vma, unsigned long addr, > pte_t *pte, pte_t pteval) > { > #ifdef CONFIG_PTE_MARKER_UFFD_WP > + /* > + * Some platforms can customize the PTE uffd-wp bit, making it unavailable > + * even if the architecture allows providing the PTE resource. > + */ > + if (!pgtable_uffd_wp_supported()) > + return false; > + Likely we could use the uffd_supports_wp_marker() wrapper here isntead and remove the #ifdef. > bool arm_uffd_pte = false; > > /* The current status of the pte should be "cleared" before calling */ > diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h > index c0e716aec26a..6264b56ae961 100644 > --- a/include/linux/userfaultfd_k.h > +++ b/include/linux/userfaultfd_k.h > @@ -228,15 +228,15 @@ static inline bool vma_can_userfault(struct vm_area_struct *vma, > if (wp_async && (vm_flags == VM_UFFD_WP)) > return true; > > -#ifndef CONFIG_PTE_MARKER_UFFD_WP > /* > * If user requested uffd-wp but not enabled pte markers for > * uffd-wp, then shmem & hugetlbfs are not supported but only > * anonymous. > */ > - if ((vm_flags & VM_UFFD_WP) && !vma_is_anonymous(vma)) > + if ((!IS_ENABLED(CONFIG_PTE_MARKER_UFFD_WP) || > + !pgtable_uffd_wp_supported()) && This would also use the helper. > + (vm_flags & VM_UFFD_WP) && !vma_is_anonymous(vma)) > return false; > -#endif > > /* By default, allow any of anon|shmem|hugetlb */ > return vma_is_anonymous(vma) || is_vm_hugetlb_page(vma) || > @@ -437,8 +437,11 @@ static inline bool userfaultfd_wp_use_markers(struct vm_area_struct *vma) > static inline bool pte_marker_entry_uffd_wp(swp_entry_t entry) > { > #ifdef CONFIG_PTE_MARKER_UFFD_WP > - return is_pte_marker_entry(entry) && > - (pte_marker_get(entry) & PTE_MARKER_UFFD_WP); > + if (pgtable_uffd_wp_supported()) > + return is_pte_marker_entry(entry) && > + (pte_marker_get(entry) & PTE_MARKER_UFFD_WP); > + else > + return false; if (!uffd_supports_wp_marker()) return false; return is_pte_marker_entry(entry) && (pte_marker_get(entry) & PTE_MARKER_UFFD_WP); > #else > return false; > #endif > @@ -447,14 +450,19 @@ static inline bool pte_marker_entry_uffd_wp(swp_entry_t entry) > static inline bool pte_marker_uffd_wp(pte_t pte) > { > #ifdef CONFIG_PTE_MARKER_UFFD_WP Simialrly here, just do a if (!uffd_supports_wp_marker()) return false; and remove the ifdef > #endif > @@ -467,14 +475,18 @@ static inline bool pte_marker_uffd_wp(pte_t pte) > static inline bool pte_swp_uffd_wp_any(pte_t pte) > { > #ifdef CONFIG_PTE_MARKER_UFFD_WP Same here. > - if (!is_swap_pte(pte)) > - return false; > + if (pgtable_uffd_wp_supported()) { > + if (!is_swap_pte(pte)) > + return false; > > - if (pte_swp_uffd_wp(pte)) > - return true; > + if (pte_swp_uffd_wp(pte)) > + return true; > > - if (pte_marker_uffd_wp(pte)) > - return true; > + if (pte_marker_uffd_wp(pte)) > + return true; > + } else { > + return false; > + } > #endif > return false; > } > diff --git a/mm/memory.c b/mm/memory.c > index 0ba4f6b71847..4eb05c5f487b 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -1465,7 +1465,9 @@ zap_install_uffd_wp_if_needed(struct vm_area_struct *vma, > { > bool was_installed = false; > > -#ifdef CONFIG_PTE_MARKER_UFFD_WP > + if (!IS_ENABLED(CONFIG_PTE_MARKER_UFFD_WP) || !pgtable_uffd_wp_supported()) > + return false; > + Same here. -- Cheers David / dhildenb