[{"id":3683170,"web_url":"http://patchwork.ozlabs.org/comment/3683170/","msgid":"<177735961706.2183577.4033506737290437474.b4-ty@b4>","list_archive_url":null,"date":"2026-04-28T07:08:20","subject":"Re: [PATCH v5] ata: ahci: fail probe if BAR too small for claimed\n ports","submitter":{"id":87751,"url":"http://patchwork.ozlabs.org/api/people/87751/","name":"Niklas Cassel","email":"cassel@kernel.org"},"content":"On Tue, 28 Apr 2026 10:09:35 +0800, dayou5941@163.com wrote:\n> When an AHCI controller is disabled in BIOS, its HOST_CAP register may\n> contain invalid values (e.g., 0xFFFFFFFF) indicating an impossibly large\n> number of ports.\n\nIndicating an impossibly large number of ports is simply not correct.\n\nThe CAP.NP field is a zeroes based 5-bit register field, so it can represent\nvalues in the range 1-32.\n\nValues in the range 1-32 is not impossibly large, it it simply the possible\nnumber of ports defined by the standard.\n\n\n> If CAP.NP claims more ports than can physically fit\n> within the mapped BAR region, accessing port registers beyond the BAR\n> boundary causes a kernel panic.\n> \n> Add validation in ahci_init_one() to check that the BAR size is\n> sufficient for the number of ports claimed in CAP.NP. The check\n> calculates the required MMIO size as:\n> \n> [...]\n\nApplied to libata/linux.git (for-7.2), thanks!\n\nI rephrased the \"impossible number of ports\" sentence while applying.\n\n[1/1] ata: ahci: fail probe if BAR too small for claimed ports\n https://git.kernel.org/libata/linux/c/eb9c9a3a\n\nKind regards,\nNiklas","headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linux-ide@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256\n header.s=k20201202 header.b=Sp6SmTjt;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c0a:e001:db::12fc:5321; helo=sea.lore.kernel.org;\n envelope-from=linux-ide+bounces-5570-incoming=patchwork.ozlabs.org@vger.kernel.org;\n receiver=patchwork.ozlabs.org)","smtp.subspace.kernel.org;\n\tdkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org\n header.b=\"Sp6SmTjt\"","smtp.subspace.kernel.org;\n arc=none smtp.client-ip=10.30.226.201"],"Received":["from sea.lore.kernel.org (sea.lore.kernel.org\n [IPv6:2600:3c0a:e001:db::12fc:5321])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519)\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4g4WnB1Nh8z1xvV\n\tfor ; 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