From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 AB95D471CFC; Thu, 24 Sep 2026 10:08:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790244510; cv=none; b=Bq6Hzp6xGcwarGwjpwq1BQ+rmlk90c1cS/vskv66Tup7jF9LkQubidZJyC01//evum6SynEGFnNO1Q8uvtebbeiaesHRewfbu5w6KcX9JDnUca9FwsOL/zlYelLtUwlELneszulLEAnPqRVwtDjquxu/RwKzWdpMMxAdvySQCRk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790244510; c=relaxed/simple; bh=EykRrBrl5pMvUZvna1SJssJT49OHh5BFqflNGuwHeb0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=IiOhtBiVfx6l9IFjbUgIwK+Ot4s3XH9TWMLcFn1mczyYHf6iZSzmHI5hrKmGFjbrTtyKVUtbdpFNHc7EVPkfiS9t2KThpgQ8DgJizef6iAvO/z3QkGrd8Z8tbMG+HidQ8TqaE1c2G8jeLtHrAJtY4zFLXrgsA+hUcTj6Ta+ecRU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=P5n6MGK2; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="P5n6MGK2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BAFC51F00893; Thu, 24 Sep 2026 10:08:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790244502; bh=eJJYWMaIvtyGybZXxXutyXnVsQUWKbvJkU+PAxP2pXo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=P5n6MGK29mMINRCHXIC8ydY+dR/BkV3ROd/aUdApCPS+tbFHhPY9xh+IR68I0PFZX qdeg4Edf9fGFKzHej5CvdNa2YRkY0pKwBFvYUy0sQDmi8swhQP3oWtFnfxTcXfbUHP 1ZlVi6klX6hVnRO31ygdNMLxpMEYjdZIeH894C1JnC9BS/PlnPfqVEt2z+3MFrEC2R PicLxLThzW/dl8ZVGDCk5J0DJiWSl7rspSCPEHVq1HnG2MDl3siNIpqesN4z5Q7Zbh ZHj+EnHjZ0NNkfeLftPM+pEIwR7vHerabIurntNfIjJLl15srVpl7Bxc2nciD4DSb7 9ifohJ9q8AY+w== From: "Aneesh Kumar K.V (Arm)" To: linux-coco@lists.linux.dev, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, iommu@lists.linux.dev Cc: "Aneesh Kumar K.V (Arm)" , Andrew Morton , Baoquan He , Mike Rapoport , Pasha Tatashin , Pratyush Yadav , Catalin Marinas , =?UTF-8?q?Christian=20K=C3=B6nig?= , Jason Gunthorpe , Joerg Roedel , Marc Zyngier , Marek Szyprowski , Robin Murphy , Steven Price , Sumit Semwal , Suzuki K Poulose , Thomas Gleixner , Will Deacon , Russell King , Benjamin Gaignard , Brian Starkey , John Stultz , Mark Rutland , Radu Rendec , "T.J. Mercier" , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Ritesh Harjani , Shrikanth Hegde , Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Sven Schnelle , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H . Peter Anvin" , Kiryl Shutsemau , Rick Edgecombe , "K . Y . Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Long Li , Paolo Bonzini , Vitaly Kuznetsov , Andy Lutomirski , Peter Zijlstra , dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-media@vger.kernel.org, linux-mm@kvack.org Subject: [RFC PATCH v8 09/14] swiotlb: Reject misaligned restricted DMA pools for CoCo guests Date: Thu, 24 Sep 2026 15:35:24 +0530 Message-ID: <20260924100529.1398790-10-aneesh.kumar@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260924100529.1398790-1-aneesh.kumar@kernel.org> References: <20260924100529.1398790-1-aneesh.kumar@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit A restricted DMA pool is a firmware-described ownership boundary. Unlike a pool allocated by SWIOTLB itself, its base cannot be moved and its size cannot be rounded without claiming memory outside the reserved region. Confidential-computing guests may require private/shared state changes to cover units larger than PAGE_SIZE. Passing a misaligned restricted region to set_memory_decrypted() can therefore fail. Validate both the physical base and the complete reserved size with the common CoCo shared-range helper before allocating SWIOTLB metadata or performing a state transition. Perform the transition through cc_make_shared(). Cc: Marek Szyprowski Cc: Robin Murphy Signed-off-by: Aneesh Kumar K.V (Arm) --- kernel/dma/swiotlb.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index 394db93b7eb9..5f65b11260e0 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -2008,6 +2008,14 @@ static int rmem_swiotlb_device_init(struct reserved_mem *rmem, return -EINVAL; } + if (cc_platform_has(CC_ATTR_MEM_ENCRYPT) && + !cc_shared_range_valid(rmem->base, rmem->size)) { + dev_err(dev, + "Restricted DMA pool must be aligned to %#zx bytes for memory encryption\n", + cc_shared_granule_size()); + return -EINVAL; + } + /* * Since multiple devices can share the same pool, the private data, * io_tlb_mem struct, will be initialized by the first device attached @@ -2041,8 +2049,8 @@ static int rmem_swiotlb_device_init(struct reserved_mem *rmem, int ret; mem->cc_shared = true; - ret = set_memory_decrypted((unsigned long)phys_to_virt(rmem->base), - rmem->size >> PAGE_SHIFT); + ret = cc_make_shared(phys_to_virt(rmem->base), + rmem->size); if (ret) { dev_err(dev, "Failed to decrypt restricted DMA pool\n"); kfree(pool->areas); -- 2.43.0