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Reviewed-by: Alistair Popple Signed-off-by: David Hildenbrand --- lib/test_hmm.c | 32 ++++++++++---------------------- 1 file changed, 10 insertions(+), 22 deletions(-) diff --git a/lib/test_hmm.c b/lib/test_hmm.c index 155b18cd9f2af..5b144bc5c4ec7 100644 --- a/lib/test_hmm.c +++ b/lib/test_hmm.c @@ -707,34 +707,23 @@ static int dmirror_check_atomic(struct dmirror *dmirror, unsigned long start, return 0; } -static int dmirror_atomic_map(unsigned long start, unsigned long end, - struct page **pages, struct dmirror *dmirror) +static int dmirror_atomic_map(unsigned long addr, struct page *page, + struct dmirror *dmirror) { - unsigned long pfn, mapped = 0; - int i; + void *entry; /* Map the migrated pages into the device's page tables. */ mutex_lock(&dmirror->mutex); - for (i = 0, pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++, i++) { - void *entry; - - if (!pages[i]) - continue; - - entry = pages[i]; - entry = xa_tag_pointer(entry, DPT_XA_TAG_ATOMIC); - entry = xa_store(&dmirror->pt, pfn, entry, GFP_ATOMIC); - if (xa_is_err(entry)) { - mutex_unlock(&dmirror->mutex); - return xa_err(entry); - } - - mapped++; + entry = xa_tag_pointer(page, DPT_XA_TAG_ATOMIC); + entry = xa_store(&dmirror->pt, addr >> PAGE_SHIFT, entry, GFP_ATOMIC); + if (xa_is_err(entry)) { + mutex_unlock(&dmirror->mutex); + return xa_err(entry); } mutex_unlock(&dmirror->mutex); - return mapped; + return 0; } static int dmirror_migrate_finalize_and_map(struct migrate_vma *args, @@ -804,8 +793,7 @@ static int dmirror_exclusive(struct dmirror *dmirror, break; } - ret = dmirror_atomic_map(addr, addr + PAGE_SIZE, &page, dmirror); - ret = ret == 1 ? 0 : -EBUSY; + ret = dmirror_atomic_map(addr, page, dmirror); folio_unlock(folio); folio_put(folio); } From patchwork Wed Feb 26 13:22:54 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 13992392 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 750C4C021BF for ; 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[2003:cb:c747:ff00:9d85:4afb:a7df:6c45]) by smtp.gmail.com with UTF8SMTPSA id ffacd0b85a97d-390d6a32299sm2059535f8f.55.2025.02.26.05.23.01 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 26 Feb 2025 05:23:01 -0800 (PST) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, David Hildenbrand , Andrew Morton , =?utf-8?b?SsOpcsO0bWUgR2xpc3Nl?= , Simona Vetter , Alistair Popple , Jason Gunthorpe Subject: [PATCH v2 2/5] mm/memory: remove PageAnonExclusive sanity-check in restore_exclusive_pte() Date: Wed, 26 Feb 2025 14:22:54 +0100 Message-ID: <20250226132257.2826043-3-david@redhat.com> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250226132257.2826043-1-david@redhat.com> References: <20250226132257.2826043-1-david@redhat.com> MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: nQRi8C0IkuwlETB_vGKSQpuUcjSAL6vdm9eMZGtkiQs_1740576183 X-Mimecast-Originator: redhat.com content-type: text/plain; charset="US-ASCII"; x-default=true X-Rspamd-Queue-Id: DB64180019 X-Stat-Signature: w6k169yegu8egduqd379idpt7xi8s4y7 X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1740576185-810417 X-HE-Meta: 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 zSfdNAX9 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 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: In commit b832a354d787 ("mm/memory: page_add_anon_rmap() -> folio_add_anon_rmap_pte()") we accidentally changed the sanity check to essentially ignore anonymous folio by mis-placing the "!" ... but we really always only get anonymous folios in restore_exclusive_pte(). However, in the meantime we removed the separate "writable device-exclusive entries" and always detect if the PTE can be writable using can_change_pte_writable() -- which also consults PageAnonExclusive. So let's just get rid of this sanity check completely. Signed-off-by: David Hildenbrand --- mm/memory.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 567b45e5d149e..507045fa719cc 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -740,9 +740,6 @@ static void restore_exclusive_pte(struct vm_area_struct *vma, pte = pte_mkdirty(pte); pte = pte_mkwrite(pte, vma); } - - VM_BUG_ON_FOLIO(pte_write(pte) && (!folio_test_anon(folio) && - PageAnonExclusive(page)), folio); set_pte_at(vma->vm_mm, address, ptep, pte); /* From patchwork Wed Feb 26 13:22:55 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 13992391 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1B7A3C021B8 for ; Wed, 26 Feb 2025 13:23:16 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4CA82280021; 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[2003:cb:c747:ff00:9d85:4afb:a7df:6c45]) by smtp.gmail.com with UTF8SMTPSA id 5b1f17b1804b1-43aba549eb9sm21310625e9.37.2025.02.26.05.23.03 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 26 Feb 2025 05:23:03 -0800 (PST) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, David Hildenbrand , Andrew Morton , =?utf-8?b?SsOpcsO0bWUgR2xpc3Nl?= , Simona Vetter , Alistair Popple , Jason Gunthorpe Subject: [PATCH v2 3/5] mm/memory: pass folio and pte to restore_exclusive_pte() Date: Wed, 26 Feb 2025 14:22:55 +0100 Message-ID: <20250226132257.2826043-4-david@redhat.com> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250226132257.2826043-1-david@redhat.com> References: <20250226132257.2826043-1-david@redhat.com> MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: LI2qoK6I70X-MIkm-wTXeFHNZaHs1waIYuSGCIOLg1c_1740576184 X-Mimecast-Originator: redhat.com content-type: text/plain; charset="US-ASCII"; x-default=true X-Rspam-User: X-Rspamd-Queue-Id: BB7B218001E X-Stat-Signature: hhqbjf39gmu8ogqtynoopiep1uawdfwm X-Rspamd-Server: rspam03 X-HE-Tag: 1740576187-652790 X-HE-Meta: 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 HiVAP6Af 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 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: Let's pass the folio and the pte to restore_exclusive_pte(), so we can avoid repeated page_folio() and ptep_get(). To do that, pass the pte to try_restore_exclusive_pte() and use a folio in there already. While at it, just avoid the "swp_entry_t entry" variable in try_restore_exclusive_pte() and add a folio-locked check to restore_exclusive_pte(). Reviewed-by: Alistair Popple Signed-off-by: David Hildenbrand --- mm/memory.c | 29 ++++++++++++++--------------- 1 file changed, 14 insertions(+), 15 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 507045fa719cc..2a0b4dd858769 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -719,14 +719,13 @@ struct folio *vm_normal_folio_pmd(struct vm_area_struct *vma, #endif static void restore_exclusive_pte(struct vm_area_struct *vma, - struct page *page, unsigned long address, - pte_t *ptep) + struct folio *folio, struct page *page, unsigned long address, + pte_t *ptep, pte_t orig_pte) { - struct folio *folio = page_folio(page); - pte_t orig_pte; pte_t pte; - orig_pte = ptep_get(ptep); + VM_WARN_ON_FOLIO(!folio_test_locked(folio), folio); + pte = pte_mkold(mk_pte(page, READ_ONCE(vma->vm_page_prot))); if (pte_swp_soft_dirty(orig_pte)) pte = pte_mksoft_dirty(pte); @@ -753,16 +752,15 @@ static void restore_exclusive_pte(struct vm_area_struct *vma, * Tries to restore an exclusive pte if the page lock can be acquired without * sleeping. */ -static int -try_restore_exclusive_pte(pte_t *src_pte, struct vm_area_struct *vma, - unsigned long addr) +static int try_restore_exclusive_pte(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, pte_t orig_pte) { - swp_entry_t entry = pte_to_swp_entry(ptep_get(src_pte)); - struct page *page = pfn_swap_entry_to_page(entry); + struct page *page = pfn_swap_entry_to_page(pte_to_swp_entry(orig_pte)); + struct folio *folio = page_folio(page); - if (trylock_page(page)) { - restore_exclusive_pte(vma, page, addr, src_pte); - unlock_page(page); + if (folio_trylock(folio)) { + restore_exclusive_pte(vma, folio, page, addr, ptep, orig_pte); + folio_unlock(folio); return 0; } @@ -868,7 +866,7 @@ copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, * (ie. COW) mappings. */ VM_BUG_ON(!is_cow_mapping(src_vma->vm_flags)); - if (try_restore_exclusive_pte(src_pte, src_vma, addr)) + if (try_restore_exclusive_pte(src_vma, addr, src_pte, orig_pte)) return -EBUSY; return -ENOENT; } else if (is_pte_marker_entry(entry)) { @@ -4030,7 +4028,8 @@ static vm_fault_t remove_device_exclusive_entry(struct vm_fault *vmf) vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, &vmf->ptl); if (likely(vmf->pte && pte_same(ptep_get(vmf->pte), vmf->orig_pte))) - restore_exclusive_pte(vma, vmf->page, vmf->address, vmf->pte); + restore_exclusive_pte(vma, folio, vmf->page, vmf->address, + vmf->pte, vmf->orig_pte); if (vmf->pte) pte_unmap_unlock(vmf->pte, vmf->ptl); From patchwork Wed Feb 26 13:22:56 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 13992390 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id B0EAAC18E7C for ; 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Signed-off-by: David Hildenbrand --- mm/memory.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/mm/memory.c b/mm/memory.c index 2a0b4dd858769..50a305d7efcb9 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -718,6 +718,32 @@ struct folio *vm_normal_folio_pmd(struct vm_area_struct *vma, } #endif +/** + * restore_exclusive_pte - Restore a device-exclusive entry + * @vma: VMA covering @address + * @folio: the mapped folio + * @page: the mapped folio page + * @address: the virtual address + * @ptep: pte pointer into the locked page table mapping the folio page + * @orig_pte: pte value at @ptep + * + * Restore a device-exclusive non-swap entry to an ordinary present pte. + * + * The folio and the page table must be locked, and MMU notifiers must have + * been called to invalidate any (exclusive) device mappings. + * + * Locking the folio makes sure that anybody who just converted the pte to + * a device-exclusive entry can map it into the device to make forward + * progress without others converting it back until the folio was unlocked. + * + * If the folio lock ever becomes an issue, we can stop relying on the folio + * lock; it might make some scenarios with heavy thrashing less likely to + * make forward progress, but these scenarios might not be valid use cases. + * + * Note that the folio lock does not protect against all cases of concurrent + * page table modifications (e.g., MADV_DONTNEED, mprotect), so device drivers + * must use MMU notifiers to sync against any concurrent changes. + */ static void restore_exclusive_pte(struct vm_area_struct *vma, struct folio *folio, struct page *page, unsigned long address, pte_t *ptep, pte_t orig_pte) From patchwork Wed Feb 26 13:22:57 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 13992393 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 889FAC18E7C for ; Wed, 26 Feb 2025 13:23:21 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 280B1280044; 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[2003:cb:c747:ff00:9d85:4afb:a7df:6c45]) by smtp.gmail.com with UTF8SMTPSA id 5b1f17b1804b1-43aba544029sm21379795e9.29.2025.02.26.05.23.06 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 26 Feb 2025 05:23:06 -0800 (PST) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, David Hildenbrand , Andrew Morton , =?utf-8?b?SsOpcsO0bWUgR2xpc3Nl?= , Simona Vetter , Alistair Popple , Jason Gunthorpe Subject: [PATCH v2 5/5] mm/mmu_notifier: use MMU_NOTIFY_CLEAR in remove_device_exclusive_entry() Date: Wed, 26 Feb 2025 14:22:57 +0100 Message-ID: <20250226132257.2826043-6-david@redhat.com> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250226132257.2826043-1-david@redhat.com> References: <20250226132257.2826043-1-david@redhat.com> MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: mK27Cq-F2uc3oFHvODPrBoOpKyvZfkDU932s7HtscDY_1740576187 X-Mimecast-Originator: redhat.com content-type: text/plain; charset="US-ASCII"; x-default=true X-Rspam-User: X-Rspamd-Queue-Id: 3A76A1C0021 X-Rspamd-Server: rspam12 X-Stat-Signature: gsjpthf7e9i8weyhj7ome8uehcpno1i9 X-HE-Tag: 1740576190-989901 X-HE-Meta: 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 QqwwUaT3 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 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: Let's limit the use of MMU_NOTIFY_EXCLUSIVE to the case where we convert a present PTE to device-exclusive. For the other case, we can simply use MMU_NOTIFY_CLEAR, because it really is clearing the device-exclusive entry first, to then install the present entry. Update the documentation of MMU_NOTIFY_EXCLUSIVE, to document the single use case more thoroughly. If ever required, we could add a separate MMU_NOTIFY_CLEAR_EXCLUSIVE; for now using MMU_NOTIFY_CLEAR seems to be sufficient. Signed-off-by: David Hildenbrand --- include/linux/mmu_notifier.h | 8 ++++---- mm/memory.c | 2 +- 2 files changed, 5 insertions(+), 5 deletions(-) diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h index d4e7146618262..bc2402a45741d 100644 --- a/include/linux/mmu_notifier.h +++ b/include/linux/mmu_notifier.h @@ -43,10 +43,10 @@ struct mmu_interval_notifier; * a device driver to possibly ignore the invalidation if the * owner field matches the driver's device private pgmap owner. * - * @MMU_NOTIFY_EXCLUSIVE: to signal a device driver that the device will no - * longer have exclusive access to the page. When sent during creation of an - * exclusive range the owner will be initialised to the value provided by the - * caller of make_device_exclusive(), otherwise the owner will be NULL. + * @MMU_NOTIFY_EXCLUSIVE: conversion of a page table entry to device-exclusive. + * The owner is initialized to the value provided by the caller of + * make_device_exclusive(), such that this caller can filter out these + * events. */ enum mmu_notifier_event { MMU_NOTIFY_UNMAP = 0, diff --git a/mm/memory.c b/mm/memory.c index 50a305d7efcb9..79acd2d95dcff 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4046,7 +4046,7 @@ static vm_fault_t remove_device_exclusive_entry(struct vm_fault *vmf) folio_put(folio); return ret; } - mmu_notifier_range_init_owner(&range, MMU_NOTIFY_EXCLUSIVE, 0, + mmu_notifier_range_init_owner(&range, MMU_NOTIFY_CLEAR, 0, vma->vm_mm, vmf->address & PAGE_MASK, (vmf->address & PAGE_MASK) + PAGE_SIZE, NULL); mmu_notifier_invalidate_range_start(&range);