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b=agpaY+P4KUx0qtOscY2YniRIGhK0x3eG6O1+40xZrESDmvU9/idS72HZed5UU+sio Fjj/F7TdBvlf0PMqxd+I7si4BdeLejW4RuWS1QQu2QfAwMsHC/rfPbDPZhh9Qmy2NX TGK4sj21RlveIPlViwTelpCD08QlRTsgeANZXKuTBqiWh8KhM90x/VwQm6S01XExQk 7K7uAqb2eED7CltQbaNfwltueatsrB27Vj7EPvnHZscLEOX6RsUB3R1JN0vj44d6H+ fRMZKNF5VEFfuRi4dNAVCxl+uOYDprvZnm9O5ajdCYgS6U7WGjjQala632RUG3idHD bRl2OIIk4Z/cw== From: Leon Romanovsky To: Marek Szyprowski , Jens Axboe , Christoph Hellwig , Keith Busch Cc: Leon Romanovsky , Jake Edge , Jonathan Corbet , Jason Gunthorpe , Zhu Yanjun , Robin Murphy , Joerg Roedel , Will Deacon , Sagi Grimberg , Bjorn Helgaas , Logan Gunthorpe , Yishai Hadas , Shameer Kolothum , Kevin Tian , Alex Williamson , =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= , Andrew Morton , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-rdma@vger.kernel.org, iommu@lists.linux.dev, linux-nvme@lists.infradead.org, linux-pci@vger.kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org, Niklas Schnelle , Chuck Lever , Luis Chamberlain , Matthew Wilcox , Dan Williams , Kanchan Joshi , Chaitanya Kulkarni Subject: [PATCH v9 10/24] mm/hmm: let users to tag specific PFN with DMA mapped bit Date: Wed, 23 Apr 2025 11:13:01 +0300 Message-ID: <0a7c1e06269eee12ff8912fe0da4b7692081fcde.1745394536.git.leon@kernel.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: B74FA16000F X-Stat-Signature: o37tyuqskhzihppzqyu3nnn4aenx58zf X-HE-Tag: 1745396072-79140 X-HE-Meta: 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 GpHrBDXZ wk9qz8lNTFgJR+PGoxWCvOPZ/RgnuqJLs1YZSWnWdxvI5UyieHzhb6OaVwDWDNUd7K6xsfSmyWzXBx5exKDOC3qlDxv0bUm5NchI0GNk5Y6ADpZjZlx2rqX2oB7E+5SF6uIDe7WuLCMki27Dr+i/gDhX4XGPuVx3D1OQqkOX4wE5pmC1nWT8Pnrk1rtW7YkS54UyhXwpdcj+Tl8u1kbmh1PH72oueRgQhoNZRfphQ0FT1fDA= 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: From: Leon Romanovsky Introduce new sticky flag (HMM_PFN_DMA_MAPPED), which isn't overwritten by HMM range fault. Such flag allows users to tag specific PFNs with information if this specific PFN was already DMA mapped. Tested-by: Jens Axboe Reviewed-by: Christoph Hellwig Signed-off-by: Leon Romanovsky --- include/linux/hmm.h | 17 +++++++++++++++ mm/hmm.c | 51 ++++++++++++++++++++++++++++----------------- 2 files changed, 49 insertions(+), 19 deletions(-) diff --git a/include/linux/hmm.h b/include/linux/hmm.h index 126a36571667..a1ddbedc19c0 100644 --- a/include/linux/hmm.h +++ b/include/linux/hmm.h @@ -23,6 +23,8 @@ struct mmu_interval_notifier; * HMM_PFN_WRITE - if the page memory can be written to (requires HMM_PFN_VALID) * HMM_PFN_ERROR - accessing the pfn is impossible and the device should * fail. ie poisoned memory, special pages, no vma, etc + * HMM_PFN_DMA_MAPPED - Flag preserved on input-to-output transformation + * to mark that page is already DMA mapped * * On input: * 0 - Return the current state of the page, do not fault it. @@ -36,6 +38,13 @@ enum hmm_pfn_flags { HMM_PFN_VALID = 1UL << (BITS_PER_LONG - 1), HMM_PFN_WRITE = 1UL << (BITS_PER_LONG - 2), HMM_PFN_ERROR = 1UL << (BITS_PER_LONG - 3), + + /* + * Sticky flags, carried from input to output, + * don't forget to update HMM_PFN_INOUT_FLAGS + */ + HMM_PFN_DMA_MAPPED = 1UL << (BITS_PER_LONG - 7), + HMM_PFN_ORDER_SHIFT = (BITS_PER_LONG - 8), /* Input flags */ @@ -57,6 +66,14 @@ static inline struct page *hmm_pfn_to_page(unsigned long hmm_pfn) return pfn_to_page(hmm_pfn & ~HMM_PFN_FLAGS); } +/* + * hmm_pfn_to_phys() - return physical address pointed to by a device entry + */ +static inline phys_addr_t hmm_pfn_to_phys(unsigned long hmm_pfn) +{ + return __pfn_to_phys(hmm_pfn & ~HMM_PFN_FLAGS); +} + /* * hmm_pfn_to_map_order() - return the CPU mapping size order * diff --git a/mm/hmm.c b/mm/hmm.c index 082f7b7c0b9e..51fe8b011cc7 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -39,13 +39,20 @@ enum { HMM_NEED_ALL_BITS = HMM_NEED_FAULT | HMM_NEED_WRITE_FAULT, }; +enum { + /* These flags are carried from input-to-output */ + HMM_PFN_INOUT_FLAGS = HMM_PFN_DMA_MAPPED, +}; + static int hmm_pfns_fill(unsigned long addr, unsigned long end, struct hmm_range *range, unsigned long cpu_flags) { unsigned long i = (addr - range->start) >> PAGE_SHIFT; - for (; addr < end; addr += PAGE_SIZE, i++) - range->hmm_pfns[i] = cpu_flags; + for (; addr < end; addr += PAGE_SIZE, i++) { + range->hmm_pfns[i] &= HMM_PFN_INOUT_FLAGS; + range->hmm_pfns[i] |= cpu_flags; + } return 0; } @@ -202,8 +209,10 @@ static int hmm_vma_handle_pmd(struct mm_walk *walk, unsigned long addr, return hmm_vma_fault(addr, end, required_fault, walk); pfn = pmd_pfn(pmd) + ((addr & ~PMD_MASK) >> PAGE_SHIFT); - for (i = 0; addr < end; addr += PAGE_SIZE, i++, pfn++) - hmm_pfns[i] = pfn | cpu_flags; + for (i = 0; addr < end; addr += PAGE_SIZE, i++, pfn++) { + hmm_pfns[i] &= HMM_PFN_INOUT_FLAGS; + hmm_pfns[i] |= pfn | cpu_flags; + } return 0; } #else /* CONFIG_TRANSPARENT_HUGEPAGE */ @@ -230,14 +239,14 @@ static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr, unsigned long cpu_flags; pte_t pte = ptep_get(ptep); uint64_t pfn_req_flags = *hmm_pfn; + uint64_t new_pfn_flags = 0; if (pte_none_mostly(pte)) { required_fault = hmm_pte_need_fault(hmm_vma_walk, pfn_req_flags, 0); if (required_fault) goto fault; - *hmm_pfn = 0; - return 0; + goto out; } if (!pte_present(pte)) { @@ -253,16 +262,14 @@ static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr, cpu_flags = HMM_PFN_VALID; if (is_writable_device_private_entry(entry)) cpu_flags |= HMM_PFN_WRITE; - *hmm_pfn = swp_offset_pfn(entry) | cpu_flags; - return 0; + new_pfn_flags = swp_offset_pfn(entry) | cpu_flags; + goto out; } required_fault = hmm_pte_need_fault(hmm_vma_walk, pfn_req_flags, 0); - if (!required_fault) { - *hmm_pfn = 0; - return 0; - } + if (!required_fault) + goto out; if (!non_swap_entry(entry)) goto fault; @@ -304,11 +311,13 @@ static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr, pte_unmap(ptep); return -EFAULT; } - *hmm_pfn = HMM_PFN_ERROR; - return 0; + new_pfn_flags = HMM_PFN_ERROR; + goto out; } - *hmm_pfn = pte_pfn(pte) | cpu_flags; + new_pfn_flags = pte_pfn(pte) | cpu_flags; +out: + *hmm_pfn = (*hmm_pfn & HMM_PFN_INOUT_FLAGS) | new_pfn_flags; return 0; fault: @@ -448,8 +457,10 @@ static int hmm_vma_walk_pud(pud_t *pudp, unsigned long start, unsigned long end, } pfn = pud_pfn(pud) + ((addr & ~PUD_MASK) >> PAGE_SHIFT); - for (i = 0; i < npages; ++i, ++pfn) - hmm_pfns[i] = pfn | cpu_flags; + for (i = 0; i < npages; ++i, ++pfn) { + hmm_pfns[i] &= HMM_PFN_INOUT_FLAGS; + hmm_pfns[i] |= pfn | cpu_flags; + } goto out_unlock; } @@ -507,8 +518,10 @@ static int hmm_vma_walk_hugetlb_entry(pte_t *pte, unsigned long hmask, } pfn = pte_pfn(entry) + ((start & ~hmask) >> PAGE_SHIFT); - for (; addr < end; addr += PAGE_SIZE, i++, pfn++) - range->hmm_pfns[i] = pfn | cpu_flags; + for (; addr < end; addr += PAGE_SIZE, i++, pfn++) { + range->hmm_pfns[i] &= HMM_PFN_INOUT_FLAGS; + range->hmm_pfns[i] |= pfn | cpu_flags; + } spin_unlock(ptl); return 0; -- 2.49.0