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AFNElJ9FNe3NpWPRwQsjHkeYI4SY5xZDFvPPkIrYFPBam+eUZNy/IkCPA0rJt3LTbaliy0e9q1lc9PtodA==@kvack.org X-Gm-Message-State: AOJu0Ywze18Ny+Q18ADpy0FwGJosuIQ+JaePPoEdY5gzVtlkhFInHRnz GLZCxlbMFYweXNuvMIRHGHEUy6Z7YtKBTCF248o7ZTfDwPmn1ssx2GiKyUtPeyUsk8bgDp6L/zf 68+uMob7rQbiJsw== X-Received: from pfbmb14.prod.google.com ([2002:a05:6a00:760e:b0:838:5125:b5e4]) (user=skhawaja job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:3003:b0:835:42cf:1f7a with SMTP id d2e1a72fcca58-83921ef6cf1mr905533b3a.6.1777940865363; Mon, 04 May 2026 17:27:45 -0700 (PDT) Date: Tue, 5 May 2026 00:27:37 +0000 In-Reply-To: <20260505002737.2213734-1-skhawaja@google.com> Mime-Version: 1.0 References: <20260505002737.2213734-1-skhawaja@google.com> X-Mailer: git-send-email 2.54.0.545.g6539524ca2-goog Message-ID: <20260505002737.2213734-5-skhawaja@google.com> Subject: [RFC PATCH 4/4] 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" X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: CEEE640003 X-Rspam-User: X-Stat-Signature: w5f4c1xpjwc13a9dbt8crg6p53xagcq4 X-HE-Tag: 1777940866-575318 X-HE-Meta: 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 NgKhGMtF 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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 | 52 +++++++++++++++++++++++++++++++++++++ 2 files changed, 102 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..c315b74a0884 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 +630,56 @@ 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); + +#ifdef CONFIG_DMA_DECLARE_COHERENT + return -EOPNOTSUPP; +#endif + + 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); + + WARN_ON_ONCE(!dev->coherent_dma_mask); + +#ifdef CONFIG_DMA_DECLARE_COHERENT + return NULL; +#endif + + if (dma_alloc_direct(dev, ops)) + return dma_direct_restore_allocation(dev, size, dma_handle, + gfp, attrs, state); + + return NULL; +} +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) { -- 2.54.0.545.g6539524ca2-goog