From patchwork Fri Jan 17 10:03:41 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Leon Romanovsky X-Patchwork-Id: 13943142 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B67B820103B; Fri, 17 Jan 2025 10:04:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737108272; cv=none; b=Uy+QqfOrMA2iA7cdsJmVePYlspRRJ4aHs9WmQ6YtsIox2M254W0cRWkeS9GSZxXYK+rBj/cQF1Zs9ASHYXH2BOFN1rxMepJ0LoVTIc6A0/1/995jGmu3ISd/EOsDWrXvNbRJhTwyxFNZgxAb9o8Y5AZx71fOg9J+yYg9upBxHiI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737108272; c=relaxed/simple; bh=In+edwZaKe3io90YLtv4jjZtq6muAkpbvftk2SGeHaY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=U+9sCYI8+3dcKnyxE86zqcP4sByc5Ydtji3kpHioOScqkbdj1cjLs1rJmVqDpXCkBq3DT3lU3KD2xvQE0AeGZY1Z5dFyxAxpiJ90a0w/qg7yAgpRLPGdxqNe+fANdeaZc7WNA5bO5C67fdwMRnGELNfCYs00aiLcQbSVSVONZdI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=cxib5n7O; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="cxib5n7O" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8AC4EC4CEDD; Fri, 17 Jan 2025 10:04:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1737108272; bh=In+edwZaKe3io90YLtv4jjZtq6muAkpbvftk2SGeHaY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cxib5n7OJ4awdwP9n9ns3nBcyKLJpElFKANRoB+QeGzY2n8K+dzz9u4siNPoi/ZnW Kf2WnGEWbgoEw9iGxK03Z4nR7BFjomVC4rzGpC6Vrfs+xVBgJXjtijNOXpqddYAckb PCWupB6fuyFakIhYaGkH/Gz9iDn9q8MwXlPbPdAUoTEX8G9wNd59qIGSPJqDk6oRM3 BKJl1Pieag1pVLLq8efeLNN7WKuLpAofCUz54s6lVSkTdKz4tp92eiZbwNL4vmEg5A wyXUt4T215wqVCJBt9DlaTkJ3mdqoZRm/yKP0XJzJFb0eWhGiwB/yi3S7nmrxG8cTN 9a3+9jsvMWZZQ== From: Leon Romanovsky To: Cc: Leon Romanovsky , Jens Axboe , Joerg Roedel , Will Deacon , Sagi Grimberg , "Keith Busch" , "Bjorn Helgaas" , "Logan Gunthorpe" , "Yishai Hadas" , "Shameer Kolothum" , "Kevin Tian" , "Alex Williamson" , "Marek Szyprowski" , =?utf-8?b?SsOpcsO0bWUgR2xp?= =?utf-8?b?c3Nl?= , "Andrew Morton" , "Jonathan Corbet" , 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, "Randy Dunlap" Subject: [PATCH v6 10/17] mm/hmm: let users to tag specific PFN with DMA mapped bit Date: Fri, 17 Jan 2025 12:03:41 +0200 Message-ID: <0f89921b4197830f410330ae7a5e89ecbe7739d5.1737106761.git.leon@kernel.org> X-Mailer: git-send-email 2.47.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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. 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 7e0229ae4a5a..da5743f6d854 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;