From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.12]) (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 094761805E for ; Wed, 31 Jul 2024 19:21:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.12 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722453688; cv=none; b=oYI9w4l3x0yTn1RfcHEncU8fGWG5/O0HmsDFVFuN/zmGPPla+0HMxNp13UQ4FueBdJaOE0Hb2cbScFsJF64e+aFkyjYhw8LR3Zo/7eFI2duEYzXOcZXoQ387wgmCWDvvZOQ3fqYNUvkB1Tu1s/O2K2PUX4j8D1Pq7mwclneb2E0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722453688; c=relaxed/simple; bh=6IvWwpyjqfXLTR+20e8TFSvRWCLrzm6hoo1iBeVsowA=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Upg0xl8R+Pdv/Ica8QWABd23sZRKNZ0RnemrVi0p8a5V7mO2c/zDOWM++p9+aZArDmvlMnjQY4xmUSjb7MDLzoV+OpQUG6WaSQzhJX34dxxFiEdZroC5Z+7P6n7VRG0QiNBIhor22mtSmg/WdMs8bLFa7tkoxUCq2JZ11Vjt1Yw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=LiEo/Iq7; arc=none smtp.client-ip=198.175.65.12 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="LiEo/Iq7" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1722453687; x=1753989687; h=date:from:to:cc:subject:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=6IvWwpyjqfXLTR+20e8TFSvRWCLrzm6hoo1iBeVsowA=; b=LiEo/Iq76u0aYuvB6+zs/rbE2/owp2DKL6Wss9kD5GRNohObzw5GJndY EArLZLngW1MKZjqOcqJbQ9TYq8cl5rX4W/11VrTxt4M1PUFODHFEZs+9R BGw4cq+QSYQsU0ZrpX6+NmUV5okmO9SmiTXT0zU056ScCMLW1/5dobs1C eBJhDNs36ZWzG20s7MVYOr7hRHSr1yQtPD6K50fQFdyyMqHuEUpvxQ0cn PuYC7+fnFg+RGWKQlkVqJFHjlQw2Q69QV19/4PBYlRkHwhFNGWF9thJTi Ip6uzMYgYPbVyEewb0M5+F6YznaV+4BaJnzxF5MksHhhufpFfHHflNvo2 A==; X-CSE-ConnectionGUID: 08EFMU6HQOKo7vLM5S6LDw== X-CSE-MsgGUID: 6o1fnsP/R/ioMF0Blh7Mmg== X-IronPort-AV: E=McAfee;i="6700,10204,11150"; a="31749586" X-IronPort-AV: E=Sophos;i="6.09,251,1716274800"; d="scan'208";a="31749586" Received: from orviesa002.jf.intel.com ([10.64.159.142]) by orvoesa104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 31 Jul 2024 12:21:26 -0700 X-CSE-ConnectionGUID: 7HV5NXGgQwO9tFR9o9sL0w== X-CSE-MsgGUID: KnGvafMYSAuFMTCzNV8B+Q== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.09,251,1716274800"; d="scan'208";a="85409033" Received: from unknown (HELO localhost) ([10.2.132.131]) by orviesa002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 31 Jul 2024 12:21:25 -0700 Date: Wed, 31 Jul 2024 12:21:24 -0700 From: Nirmal Patel To: Christoph Hellwig Cc: linux-pci@vger.kernel.org, paul.m.stillwell.jr@intel.com, Jim Harris Subject: Re: [PATCH] PCI: fixup PCI_INTERRUPT_LINE for VMD downstream devices Message-ID: <20240731122124.00005889@linux.intel.com> In-Reply-To: References: <20240724170040.5193-1-nirmal.patel@linux.intel.com> X-Mailer: Claws Mail 4.2.0 (GTK 3.24.41; x86_64-w64-mingw32) Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Wed, 24 Jul 2024 11:36:31 -0700 Christoph Hellwig wrote: > On Wed, Jul 24, 2024 at 10:00:40AM -0700, Nirmal Patel wrote: > > +#if IS_ENABLED(CONFIG_VMD) > > +/* > > + * VMD does not support legacy interrupts for downstream devices. > > + * So PCI_INTERRPUT_LINE needs to be initialized to 0 to ensure OS > > + * doesn't try to configure a legacy irq. > > + */ > > The wording is a bit weird, Linux is the OS normally. Or is this > about guest OSes in virtualized environments? Given how VMD bypasses > a lot of boundaries can we even assign individual devices to VFIO? > And if so is that actually safe or should we prohibit it? > This is for host OS. I will add better description as suggested by Mani.