From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed1-f49.google.com (mail-ed1-f49.google.com [209.85.208.49]) (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 D3DC943F8AE for ; Tue, 28 Jul 2026 14:27:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.49 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785248828; cv=none; b=OAZuEvimMpJ8W7dMJIQn/ApCE4IFE5+jQseateewgp4WdAcYp/Bxus8X9vdgeJlfS/zSJ9yYhN7U0wqWrZjaCEF3ZUrlQq0MEt11hne6ZQo6eSsMCisEyKE4J/HQYHIFSKb5+ZZZ+vzpatN2vEBY3avnuocS1w5rsA+qKKBPeOU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785248828; c=relaxed/simple; bh=gVq0Fz3g+XDQCPf7dOicHGB4Jxifut+ZUEFvN2XpjTs=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=rkZd8FiiM90suI+utAiycEXLG/gm6uj24PPrJvlEFFY7d2LQeSc3TwngWrhuAQJy4nF9uDz0g27DhcbD6Et5078NSQ3FIqd6m3DAZq0GwUNyoJBvsFd9gbqVDTztJMlfNxqwXp62LxJW7rtdXFP+SyMt0cCqHqryzdITiuSoNC4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=N1uxR3xG; arc=none smtp.client-ip=209.85.208.49 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=google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="N1uxR3xG" Received: by mail-ed1-f49.google.com with SMTP id 4fb4d7f45d1cf-69fec8b4638so12821a12.0 for ; Tue, 28 Jul 2026 07:27:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1785248825; x=1785853625; darn=vger.kernel.org; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:from:to:cc:subject :date:message-id:reply-to:content-type; bh=xBoFAKEkC+vfpGEapr3+3YEZ3mSu2No6TKaGaOQmWRI=; b=N1uxR3xGwIOq3PFLjIc6nOFegsWg56RS5bY7qck/BUgZKWbVI4yWC57v/iNdGa4OPB cR67wB0qJ+XWsjELe9Nk9y73I1Fs/YjyqRb0V/mdezT1lmjwq0JLPMj9IeiKhnpmn620 F/ou0btUiIdS+iWn3D45hMIiIwRkADIFS+Xo9xN2+n05u/nbkjJGjr0Sy3XHAiXxde79 q+Ne9jqPnfJbSo0ZkZPZEIulcVH0nlCPauuhQgGe9lKA9d+aHwslE3+tzkwxsSz30VhL YDJe2YODmO8yj53MqhcDu9VTqa25ArVzSPAxwMQsv7lt91a6gf6+aeD4QD2PS2I3kMVz kP5w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1785248825; x=1785853625; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=xBoFAKEkC+vfpGEapr3+3YEZ3mSu2No6TKaGaOQmWRI=; b=pz3/acCPraXu2wJkQs76oIr9xwW8D2/cOM6BxFDy+d8o1j4biuzoOXnWJaYaLeF1VX d3wfj/59EL5obOAZGxKVJ2VOs7fuz92roGjRg+Fj+GdFNeBrou09rKHU/JFNkYR0SEQX /GNPv4qYZo/JTqCJdXH/3CJC1zdQgnyKRmTmmjmHVbzn/09ZD6y1rkvlPiNrZcdmK9T9 g6ZRDEV5pc0zYm5eL5LseyCOtt08wo9JYGpK2pJfs9nij7toz3D3TQ5bAiW3k6wEWNi1 r4V61/8Im07JPAJvH1XYxu3HhWZIQtVw4GObsILFjdwOKX/WMn6bsynLSNdXIUfA4KsP /Dvw== X-Forwarded-Encrypted: i=1; AHgh+RpWuWi6vVwNOoDoGJ4o/n5/igeN7DxRbamHRBeje5WTxQ30BYnHLKuC4PYuWGqPyqfeFra0QymYsB52@vger.kernel.org X-Gm-Message-State: AOJu0Yyuv8B5ZhTzNGohL44Ae/HipTJVWE5bU9dGDulGSRIJ0N9JxcLE NqC1b2R7zrb5XAtdI5DkoivuDwN/XQn/c44p9EIXSeebmGmhIK3vAjNCcaDIBUM0Mw== X-Gm-Gg: AR+sD12gsAcSGYrgkKMcEebz8FR7TKzt/tQSWDnDsafi/6XfipJmvAdGrzmzGnVkZby H8HvlvKUUANIYZ4y1aI4O9ULDi6jkOOKBPbpeO3T5NHyja0hkunU/XsXBHYDFzNBwr5VqOcVBOe Z/f6Mj+Xw1prk65U1w9vV978BJvh8c/SXplB4GmMMsV+//CbWvPxDNf6GnJAZ0Rr27h3w3jddZN BrPgr4g3/XFThE+Sm8C8LF91Pccax0XNcCJHa+DwUUrz8sWGAx17vgDh+XpWQp+o5iuedAN9E6+ nodMU1fGqPY29CNxNpp6HGD3OC1tJgJO/y/A58jAVKsku42NeN7sbpIJr8+z3HJl6npthNOKIQp Ya8PfikyN94bN2H1z4BH6rE5gHAED9o0K0YktoIFTIEMYnZOoc2ep03GMKjU/L/osVUu6zyuApm hWsadrCAaIDkwWs1LbxJnUgkbBKO4ySOnwXbyiE4e+r8E= X-Received: by 2002:a05:6402:a20f:10b0:697:e82f:e4f2 with SMTP id 4fb4d7f45d1cf-69fb80feebemr4712a12.4.1785248824492; Tue, 28 Jul 2026 07:27:04 -0700 (PDT) Received: from google.com (250.192.189.35.bc.googleusercontent.com. [35.189.192.250]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-69fb594622asm4455060a12.26.2026.07.28.07.27.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 28 Jul 2026 07:27:03 -0700 (PDT) Date: Tue, 28 Jul 2026 14:26:56 +0000 From: Mostafa Saleh To: "Aneesh Kumar K.V (Arm)" Cc: iommu@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-coco@lists.linux.dev, Robin Murphy , Marek Szyprowski , Will Deacon , Marc Zyngier , Steven Price , Suzuki K Poulose , Catalin Marinas , Jiri Pirko , Jason Gunthorpe , Petr Tesarik , Alexey Kardashevskiy , Dan Williams , Xu Yilun , linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , "Christophe Leroy (CS GROUP)" , Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Sven Schnelle , x86@kernel.org, Jason Gunthorpe , Jiri Pirko , Michael Kelley Subject: Re: [PATCH v8 07/23] dma-direct: swiotlb: handle swiotlb alloc/free outside __dma_direct_alloc_pages Message-ID: References: <20260717180442.110954-1-aneesh.kumar@kernel.org> <20260717180442.110954-8-aneesh.kumar@kernel.org> Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260717180442.110954-8-aneesh.kumar@kernel.org> On Fri, Jul 17, 2026 at 11:34:25PM +0530, Aneesh Kumar K.V (Arm) wrote: > Move swiotlb allocation out of __dma_direct_alloc_pages() and handle it in > dma_direct_alloc() / dma_direct_alloc_pages(). > > This is needed for follow-up changes that simplify the handling of > memory encryption/decryption based on the DMA attribute flags. > > swiotlb backing pages are already mapped decrypted by > swiotlb_update_mem_attributes() and rmem_swiotlb_device_init(), so > dma-direct should not call dma_set_decrypted() on allocation nor > dma_set_encrypted() on free for swiotlb-backed memory. > > Update alloc/free paths to detect swiotlb-backed pages and skip > encrypt/decrypt transitions for those paths. Keep the existing highmem > rejection in dma_direct_alloc_pages() for swiotlb allocations. > > Only for "restricted-dma-pool", we currently set `for_alloc = true`, while > rmem_swiotlb_device_init() decrypts the whole pool up front. This pool is > typically used together with "shared-dma-pool", where the shared region is > accessed after remap/ioremap and the returned address is suitable for > decrypted memory access. So existing code paths remain valid. > > Reviewed-by: Jason Gunthorpe > Tested-by: Jiri Pirko > Tested-by: Michael Kelley > Tested-by: Mostafa Saleh > Signed-off-by: Aneesh Kumar K.V (Arm) Reviewed-by: Mostafa Saleh Thanks, Mostafa > --- > include/linux/swiotlb.h | 6 ++++ > kernel/dma/direct.c | 71 ++++++++++++++++++++++++++++++----------- > kernel/dma/swiotlb.c | 6 ++++ > 3 files changed, 65 insertions(+), 18 deletions(-) > > diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h > index 3dae0f592063..c92ff6791595 100644 > --- a/include/linux/swiotlb.h > +++ b/include/linux/swiotlb.h > @@ -284,6 +284,8 @@ extern void swiotlb_print_info(void); > #ifdef CONFIG_DMA_RESTRICTED_POOL > struct page *swiotlb_alloc(struct device *dev, size_t size); > bool swiotlb_free(struct device *dev, struct page *page, size_t size); > +void swiotlb_free_from_pool(struct device *dev, > + phys_addr_t tlb_addr, struct io_tlb_pool *pool); > > static inline bool is_swiotlb_for_alloc(struct device *dev) > { > @@ -299,6 +301,10 @@ static inline bool swiotlb_free(struct device *dev, struct page *page, > { > return false; > } > +static inline void swiotlb_free_from_pool(struct device *dev, > + phys_addr_t tlb_addr, struct io_tlb_pool *pool) > +{ > +} > static inline bool is_swiotlb_for_alloc(struct device *dev) > { > return false; > diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c > index a81597f8c3ed..171c89fe99c9 100644 > --- a/kernel/dma/direct.c > +++ b/kernel/dma/direct.c > @@ -96,14 +96,6 @@ static int dma_set_encrypted(struct device *dev, void *vaddr, size_t size) > return ret; > } > > -static void __dma_direct_free_pages(struct device *dev, struct page *page, > - size_t size) > -{ > - if (swiotlb_free(dev, page, size)) > - return; > - dma_free_contiguous(dev, page, size); > -} > - > static struct page *dma_direct_alloc_swiotlb(struct device *dev, size_t size) > { > struct page *page = swiotlb_alloc(dev, size); > @@ -125,9 +117,6 @@ static struct page *__dma_direct_alloc_pages(struct device *dev, size_t size, > > WARN_ON_ONCE(!PAGE_ALIGNED(size)); > > - if (is_swiotlb_for_alloc(dev)) > - return dma_direct_alloc_swiotlb(dev, size); > - > gfp |= dma_direct_optimal_gfp_mask(dev, &phys_limit); > page = dma_alloc_contiguous(dev, size, gfp); > if (page) { > @@ -203,6 +192,7 @@ void *dma_direct_alloc(struct device *dev, size_t size, > dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs) > { > bool remap = false, set_uncached = false; > + bool mark_mem_decrypt = true; > struct page *page; > void *ret; > > @@ -252,11 +242,21 @@ void *dma_direct_alloc(struct device *dev, size_t size, > return page ? ret : NULL; > } > > + if (is_swiotlb_for_alloc(dev)) { > + page = dma_direct_alloc_swiotlb(dev, size); > + if (page) { > + mark_mem_decrypt = false; > + goto setup_page; > + } > + return NULL; > + } > + > /* we always manually zero the memory once we are done */ > page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO, true); > if (!page) > return NULL; > > +setup_page: > /* > * dma_alloc_contiguous can return highmem pages depending on a > * combination the cma= arguments and per-arch setup. These need to be > @@ -283,7 +283,7 @@ void *dma_direct_alloc(struct device *dev, size_t size, > goto out_free_pages; > } else { > ret = page_address(page); > - if (dma_set_decrypted(dev, ret, size)) > + if (mark_mem_decrypt && dma_set_decrypted(dev, ret, size)) > goto out_leak_pages; > } > > @@ -300,10 +300,11 @@ void *dma_direct_alloc(struct device *dev, size_t size, > return ret; > > out_encrypt_pages: > - if (dma_set_encrypted(dev, page_address(page), size)) > + if (mark_mem_decrypt && dma_set_encrypted(dev, page_address(page), size)) > return NULL; > out_free_pages: > - __dma_direct_free_pages(dev, page, size); > + if (!swiotlb_free(dev, page, size)) > + dma_free_contiguous(dev, page, size); > return NULL; > out_leak_pages: > return NULL; > @@ -312,6 +313,9 @@ void *dma_direct_alloc(struct device *dev, size_t size, > void dma_direct_free(struct device *dev, size_t size, > void *cpu_addr, dma_addr_t dma_addr, unsigned long attrs) > { > + phys_addr_t phys; > + bool mark_mem_encrypted = true; > + struct io_tlb_pool *swiotlb_pool; > unsigned int page_order = get_order(size); > > if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) && > @@ -340,16 +344,25 @@ void dma_direct_free(struct device *dev, size_t size, > dma_free_from_pool(dev, cpu_addr, PAGE_ALIGN(size))) > return; > > + phys = dma_to_phys(dev, dma_addr); > + swiotlb_pool = swiotlb_find_pool(dev, phys); > + if (swiotlb_pool) > + /* Swiotlb doesn't need a page attribute update on free */ > + mark_mem_encrypted = false; > + > if (is_vmalloc_addr(cpu_addr)) { > vunmap(cpu_addr); > } else { > if (IS_ENABLED(CONFIG_ARCH_HAS_DMA_CLEAR_UNCACHED)) > arch_dma_clear_uncached(cpu_addr, size); > - if (dma_set_encrypted(dev, cpu_addr, size)) > + if (mark_mem_encrypted && dma_set_encrypted(dev, cpu_addr, size)) > return; > } > > - __dma_direct_free_pages(dev, dma_direct_to_page(dev, dma_addr), size); > + if (swiotlb_pool) > + swiotlb_free_from_pool(dev, phys, swiotlb_pool); > + else > + dma_free_contiguous(dev, dma_direct_to_page(dev, dma_addr), size); > } > > struct page *dma_direct_alloc_pages(struct device *dev, size_t size, > @@ -361,6 +374,15 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size, > if (force_dma_unencrypted(dev) && dma_direct_use_pool(dev, gfp)) > return dma_direct_alloc_from_pool(dev, size, dma_handle, &ret, gfp); > > + if (is_swiotlb_for_alloc(dev)) { > + page = dma_direct_alloc_swiotlb(dev, size); > + if (!page) > + return NULL; > + > + ret = page_address(page); > + goto setup_page; > + } > + > page = __dma_direct_alloc_pages(dev, size, gfp, false); > if (!page) > return NULL; > @@ -368,6 +390,7 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size, > ret = page_address(page); > if (dma_set_decrypted(dev, ret, size)) > goto out_leak_pages; > +setup_page: > memset(ret, 0, size); > *dma_handle = phys_to_dma_direct(dev, page_to_phys(page)); > return page; > @@ -379,16 +402,28 @@ void dma_direct_free_pages(struct device *dev, size_t size, > struct page *page, dma_addr_t dma_addr, > enum dma_data_direction dir) > { > + phys_addr_t phys; > void *vaddr = page_address(page); > + struct io_tlb_pool *swiotlb_pool; > + bool mark_mem_encrypted = true; > > /* If page is not from an atomic pool, dma_free_from_pool_page() fails */ > if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL) && > dma_free_from_pool_page(dev, page, size)) > return; > > - if (dma_set_encrypted(dev, vaddr, size)) > + phys = page_to_phys(page); > + swiotlb_pool = swiotlb_find_pool(dev, phys); > + if (swiotlb_pool) > + mark_mem_encrypted = false; > + > + if (mark_mem_encrypted && dma_set_encrypted(dev, vaddr, size)) > return; > - __dma_direct_free_pages(dev, page, size); > + > + if (swiotlb_pool) > + swiotlb_free_from_pool(dev, phys, swiotlb_pool); > + else > + dma_free_contiguous(dev, page, size); > } > > #if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \ > diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c > index 6e8db52866bf..d54154c165e5 100644 > --- a/kernel/dma/swiotlb.c > +++ b/kernel/dma/swiotlb.c > @@ -1815,6 +1815,12 @@ bool swiotlb_free(struct device *dev, struct page *page, size_t size) > return true; > } > > +void swiotlb_free_from_pool(struct device *dev, > + phys_addr_t tlb_addr, struct io_tlb_pool *pool) > +{ > + swiotlb_release_slots(dev, tlb_addr, pool); > +} > + > static int rmem_swiotlb_device_init(struct reserved_mem *rmem, > struct device *dev) > { > -- > 2.43.0 >