From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f202.google.com (mail-pf1-f202.google.com [209.85.210.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3410F3A9014 for ; Wed, 8 Jul 2026 23:49:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783554543; cv=none; b=P13VAAnqRilTZD7Kb6jV5mqgRNDssHtIrPA0IUhqq3+haJBpyO/idELYh8pGJvFLyfL16Qrylb2XMjvWLVaSzqk+xasftNZTaeiMbIC/vmyjJgv2KV2B+a7Wkfum6g2txfV80w62i824a4joLSMCGStGET2Fe+S+aEYCvrNUYAc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783554543; c=relaxed/simple; bh=RdRwHLtqxvz/z/PEiPampV1fF/tsKEjDL2KcdgvCuhU=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=CkfNGifX99wWSJ/tlZYOeV1RK3FlrquBSJxGHnCq7yxT7+m79plrhrJJCXHkkKkzNFzoe8O1An5CL3eAPKqeiDRoa1Tk4hqd9uTiN16N6M++Nin4OGVShNi/h+6tZKhiu3HlNDJ3R1eUPMsOA0r7fiW81Pgj3ySkdJMpUE8ydU0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--skhawaja.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=QxOE3Cvs; arc=none smtp.client-ip=209.85.210.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--skhawaja.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="QxOE3Cvs" Received: by mail-pf1-f202.google.com with SMTP id d2e1a72fcca58-8478ff5d801so2334848b3a.2 for ; Wed, 08 Jul 2026 16:49:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1783554540; x=1784159340; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=Q+S3FWpLmbV8ubn+1hh1NL45mx9rPGtnbGgWXMOw/Cc=; b=QxOE3CvspNJbaakTyEvQ0wbOkjnJXXFDXE16EqOHjtYdwiP8aH7JNZYDdil1QgnZan XnpK/M8Jc9npYCGMyO3YLAwfUByg4Zu9DiZQfo1hWb8iNNOgEgdahi+ZAXPuxLyPxu9f o9faWmp4uduPDET+3b1KaWvpqWGPzYpBYyo4+4bzot0A4dTJ60l46zSP95UtAtJ8xcn0 j9+GHXKasXKooH9zI1sbSacfCKopap5akfppnpBQyiTo73ZZ+PPxriBt5RauneugT9Y8 wPfPtrEukLniJl9HiQwPcxYCXURwQdP6bPF+12nW2qnV1nMLq49ovZjtYGFdNBxSGNFz TC7Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1783554540; x=1784159340; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=Q+S3FWpLmbV8ubn+1hh1NL45mx9rPGtnbGgWXMOw/Cc=; b=iZB3UhrO9ypMmgFmo8OTlU9KMlkYVCE6YBb71dnFg6DPVSiZkdC6/VaRKPwntjTgly +gKhvSOowTJmYj5ZijuTKG65Igsq3b3NsjKqUcGGPAJ54EPKueKMN9sl41lh10PXGNJb Ye/L5DYAbw6apWed5IckOg8dAIM+Uob7Irw5/1ebbr9mZoPCr72tdv6TdAdeOfK/7vYW levz9LlpEedupF5HWVHV+Zcy1ptUOxcr8DgVYN6GGxdN7LvlVpJhOOI6m6MRjB0hdOW4 C5vPFDHBLS+zixGuQkRlr8tpMqLqUGEhGi2HbnsPu00aaymQcUl/9i6e6JZXqIT0WbjW biYg== X-Forwarded-Encrypted: i=1; AHgh+RpbbUD/XSsvai+dTkHBm9IeQATuHP+eolksMh9JXQYEzURVdNkIYOQ6gHN1+KSBcriX55Iw8MNCslOUs+w=@vger.kernel.org X-Gm-Message-State: AOJu0YzfIBGjhh3oPbcKVK0/eGWHvkhxQ7N3jTYWJSdkZySh1eUvzfRD fC3a9Ys6Hufzt1B1Lu7URyf1AblO8Q716UT0IR8JKc4VG8DjmUSnmJVcVnWGrHgLeEG89zxIMpq wg+2Rx2cE8/AtIw== X-Received: from pfqp3.prod.google.com ([2002:aa7:9e83:0:b0:847:9570:daf0]) (user=skhawaja job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:8f0b:b0:842:708f:39be with SMTP id d2e1a72fcca58-84842fdf097mr4788740b3a.5.1783554540334; Wed, 08 Jul 2026 16:49:00 -0700 (PDT) Date: Wed, 8 Jul 2026 23:48:50 +0000 In-Reply-To: <20260708234854.4044652-1-skhawaja@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260708234854.4044652-1-skhawaja@google.com> X-Mailer: git-send-email 2.55.0.795.g602f6c329a-goog Message-ID: <20260708234854.4044652-7-skhawaja@google.com> Subject: [RFC PATCH v2 06/10] dma-mapping: Add API to preserve/restore DMA allocation From: Samiullah Khawaja To: Marek Szyprowski , Will Deacon , Jason Gunthorpe Cc: Samiullah Khawaja , Pasha Tatashin , Mike Rapoport , Pratyush Yadav , Alexander Graf , Robin Murphy , Kevin Tian , iommu@lists.linux.dev, kexec@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, David Matlack , Andrew Morton , Pranjal Shrivastava , Vipin Sharma Content-Type: text/plain; charset="UTF-8" Add new DMA APIs that allow preserving/restoring DMA allocations across live update. Signed-off-by: Samiullah Khawaja --- include/linux/dma-mapping.h | 50 +++++++++++++++++++++++++++++++++++++ kernel/dma/mapping.c | 49 ++++++++++++++++++++++++++++++++++++ 2 files changed, 99 insertions(+) diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index db8ab24a54f4..3756fc15467b 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -210,6 +210,15 @@ void *dma_vmap_noncontiguous(struct device *dev, size_t size, void dma_vunmap_noncontiguous(struct device *dev, void *vaddr); int dma_mmap_noncontiguous(struct device *dev, struct vm_area_struct *vma, size_t size, struct sg_table *sgt); +#ifdef CONFIG_DMA_LIVEUPDATE +int dma_preserve_allocation_attrs(struct device *dev, void *cpu_addr, + size_t size, dma_addr_t dma_handle, + unsigned long attrs, u64 *state); +void dma_unpreserve_allocation(struct device *dev, u64 state); +void *dma_restore_allocation_attrs(struct device *dev, size_t size, + dma_addr_t *dma_handle, gfp_t gfp, + unsigned long attrs, u64 state); +#endif #else /* CONFIG_HAS_DMA */ static inline dma_addr_t dma_map_page_attrs(struct device *dev, struct page *page, size_t offset, size_t size, @@ -496,6 +505,26 @@ static inline bool dma_need_unmap(struct device *dev) } #endif /* !CONFIG_HAS_DMA || !CONFIG_DMA_NEED_SYNC */ +#if !defined(CONFIG_DMA_LIVEUPDATE) || !defined(CONFIG_HAS_DMA) +static inline int dma_preserve_allocation_attrs(struct device *dev, void *cpu_addr, + size_t size, dma_addr_t dma_handle, + unsigned long attrs, u64 *state) +{ + return -EOPNOTSUPP; +} + +static inline void dma_unpreserve_allocation(struct device *dev, u64 state) +{ +} + +static inline void *dma_restore_allocation_attrs(struct device *dev, size_t size, + dma_addr_t *dma_handle, gfp_t gfp, + unsigned long attrs, u64 state) +{ + return NULL; +} +#endif + struct page *dma_alloc_pages(struct device *dev, size_t size, dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp); void dma_free_pages(struct device *dev, size_t size, struct page *page, @@ -618,6 +647,27 @@ static inline void *dma_alloc_coherent(struct device *dev, size_t size, (gfp & __GFP_NOWARN) ? DMA_ATTR_NO_WARN : 0); } +static inline int dma_preserve_coherent_allocation(struct device *dev, void *cpu_addr, + size_t size, dma_addr_t dma_handle, u64 *state) +{ + return dma_preserve_allocation_attrs(dev, cpu_addr, size, + dma_handle, 0, state); +} + +static inline void dma_unpreserve_coherent_allocation(struct device *dev, u64 state) +{ + dma_unpreserve_allocation(dev, state); +} + +static inline void *dma_restore_coherent_allocation(struct device *dev, size_t size, + dma_addr_t *dma_handle, + gfp_t gfp, u64 state) +{ + return dma_restore_allocation_attrs(dev, size, dma_handle, gfp, + (gfp & __GFP_NOWARN) ? DMA_ATTR_NO_WARN : 0, + state); +} + static inline void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr_t dma_handle) { diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c index 23ed8eb9233e..3b07bf30722c 100644 --- a/kernel/dma/mapping.c +++ b/kernel/dma/mapping.c @@ -12,6 +12,8 @@ #include #include #include +#include +#include #include #include #include @@ -628,6 +630,53 @@ u64 dma_get_required_mask(struct device *dev) } EXPORT_SYMBOL_GPL(dma_get_required_mask); +#ifdef CONFIG_DMA_LIVEUPDATE +int dma_preserve_allocation_attrs(struct device *dev, void *cpu_addr, + size_t size, dma_addr_t dma_handle, + unsigned long attrs, u64 *state) +{ + const struct dma_map_ops *ops = get_dma_ops(dev); + + if (dma_is_from_dev_coherent(dev, cpu_addr)) + return -EOPNOTSUPP; + + if (dma_alloc_direct(dev, ops)) + return dma_direct_preserve_allocation(dev, cpu_addr, size, + dma_handle, attrs, + state); + + return -EOPNOTSUPP; +} +EXPORT_SYMBOL(dma_preserve_allocation_attrs); + +void dma_unpreserve_allocation(struct device *dev, u64 state) +{ + const struct dma_map_ops *ops = get_dma_ops(dev); + + if (dma_alloc_direct(dev, ops)) + dma_direct_unpreserve_allocation(dev, state); +} +EXPORT_SYMBOL(dma_unpreserve_allocation); + +void *dma_restore_allocation_attrs(struct device *dev, size_t size, + dma_addr_t *dma_handle, gfp_t gfp, + unsigned long attrs, u64 state) +{ + const struct dma_map_ops *ops = get_dma_ops(dev); + void *cpu_addr = NULL; + + WARN_ON_ONCE(!dev->coherent_dma_mask); + + if (dma_alloc_direct(dev, ops)) + cpu_addr = dma_direct_restore_allocation(dev, size, dma_handle, + gfp, attrs, state); + + debug_dma_alloc_coherent(dev, size, *dma_handle, cpu_addr, attrs); + return cpu_addr; +} +EXPORT_SYMBOL(dma_restore_allocation_attrs); +#endif + void *dma_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle, gfp_t flag, unsigned long attrs) { -- 2.55.0.795.g602f6c329a-goog