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 97EC135F18A; Thu, 21 May 2026 11:54:22 +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=1779364463; cv=none; b=tEZkH3hkfKHicfwF/7mkse+BI2o6fcg/Ut26iWTLTSWNxZibHfkc8JPoPb7uDARAPtHvD21sbcbOrAWjeFKWFbA/KmYI0eBRajghGxYq+YC0rkRv4CS7A1RBq+yiYg3uHg9ByWcSVUPCujtMDGCMs1ZgbH+1WO+tgMj1I5t/bwg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779364463; c=relaxed/simple; bh=ZgZIWjW+VmcEbqu15znYRaEOpX+b7l5mNLvU3xhgsCk=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=COVXIYdINCQmqICBtu9N4DqseiiXrI8TnMCGVyOS+8s1y88Ycrbk2OSWzn4cylKyLyIk/cZjhWipULDITU63/tE/sdD8dXXASFn/d9FlswPsIiTVyLNXclw9guy6R+/6KMeugUJm0IoLtw6VTwlvEefzYBKkkRWu9DMq7kJ7+0g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=VRoV8Obk; 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="VRoV8Obk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D60901F000E9; Thu, 21 May 2026 11:54:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779364462; bh=AfaRmOFwq9PG0Q9lB7Y5h4Js0tCrSyooaZYJ9TAjF4I=; h=From:To:Cc:Subject:In-Reply-To:References:Date; b=VRoV8Obk6Db2yTrA5yAdD7bmtQFvSWYfd/ZMw0E5GBL5jIdP8p2frzgVjebJ/AI8N hR/ltXnLmqYytDDOSL4NfrAm8WWL6Eapslk7nKLHkiEPTsINTDc/s/wXE5nhOEOkw0 ocFPhIherbIJmWmA0TT9aOS8dxo5zor2QipnNUscdwsm508C2EjBqUXMBblgS8bTHy VTwtO3pIzg195ryyporAX+AUffxjuJV03eR50aV96prxY5h11jwtvbWjHvTe3DepXz Q2BR9ERr09ummMuYbcfqyARU4HAkb3n2S7jWp660Rin4hD/1ttPs8n0zhk15N2/FrI IAG1as/hVnwgg== X-Mailer: emacs 30.2 (via feedmail 11-beta-1 I) From: Aneesh Kumar K.V To: iommu@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-coco@lists.linux.dev Cc: Robin Murphy , Marek Szyprowski , Will Deacon , Marc Zyngier , Steven Price , Suzuki K Poulose , Catalin Marinas , Jiri Pirko , Jason Gunthorpe , Mostafa Saleh , 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 Subject: Re: [PATCH v4 13/13] x86/amd-gart: preserve the direct DMA address until GART mapping succeeds In-Reply-To: <20260512090408.794195-14-aneesh.kumar@kernel.org> References: <20260512090408.794195-1-aneesh.kumar@kernel.org> <20260512090408.794195-14-aneesh.kumar@kernel.org> Date: Thu, 21 May 2026 17:24:07 +0530 Message-ID: Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain "Aneesh Kumar K.V (Arm)" writes: > gart_alloc_coherent() first allocates memory through dma_direct_alloc(), > which returns a direct-mapped DMA address in dma_addr. When force_iommu is > enabled, the buffer is then remapped. > > Do not overwrite dma_addr before dma_map_area() has succeeded. Keep the > dma_map_area result in a temporary variable so the direct DMA address > remains available for dma_direct_free() on the error path. > > Signed-off-by: Aneesh Kumar K.V (Arm) > --- > arch/x86/kernel/amd_gart_64.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/kernel/amd_gart_64.c b/arch/x86/kernel/amd_gart_64.c > index b5f1f031d45b..a109649c5649 100644 > --- a/arch/x86/kernel/amd_gart_64.c > +++ b/arch/x86/kernel/amd_gart_64.c > @@ -467,18 +467,20 @@ gart_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_addr, > gfp_t flag, unsigned long attrs) > { > void *vaddr; > + dma_addr_t dma_map_addr; > > vaddr = dma_direct_alloc(dev, size, dma_addr, flag, attrs); > if (!vaddr || > !force_iommu || dev->coherent_dma_mask <= DMA_BIT_MASK(24)) > return vaddr; > > - *dma_addr = dma_map_area(dev, virt_to_phys(vaddr), size, > - DMA_BIDIRECTIONAL, > - (1UL << get_order(size)) - 1, attrs); > + dma_map_addr = dma_map_area(dev, virt_to_phys(vaddr), size, > + DMA_BIDIRECTIONAL, > + (1UL << get_order(size)) - 1, attrs); > flush_gart(); > - if (unlikely(*dma_addr == DMA_MAPPING_ERROR)) > + if (unlikely(dma_map_addr == DMA_MAPPING_ERROR)) > goto out_free; > + *dma_addr = dma_map_addr; > return vaddr; > out_free: > dma_direct_free(dev, size, vaddr, *dma_addr, attrs); > -- > 2.43.0 > This needs corresponding changes on the gart_free_coherent() side as well. https://sashiko.dev/#/patchset/20260512090408.794195-1-aneesh.kumar%40kernel.org?part=13 I will avoid making that change as part of this series, since I assume it would require specific testing. -aneesh