From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 3BEA916D9A6 for ; Wed, 24 Jul 2024 18:36:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721846194; cv=none; b=J72a+zAcGaToqAmWnlhuwjpcZcRrqU79msmfeLHDkZ+PMkFmHEVbO8vtRyo+rAqvkFtlN8kygxDdyWC2lApcvU3aIGF3XTSh/RziPb92OCW5+lfNJ88RpjPsIIRgT4eBtxAc7/T8rzFJu9dZ8vcKWY+UIoH7g1BiklGIYnxnOlM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721846194; c=relaxed/simple; bh=2eNG5TTZpb5jJwF7GKQh5V7cdavWVsBnOCdWU305yOE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=M6Zz8ZifKcl8wZFzkjBgxQz8LNWmvoEfmHtrAXeH0WyM8u2Xm4A/vaE23qAXPAOlP6zgbBIxHQ29qcZilGaAf3ScvTKbLIPKBpyRr4VuLiFilFeCo92jIpAe/NGmnz9G0OAr54tV5Uj9wX2UXn03skRuDEJjfW4WFZwRtZJ10jI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=HOgJDWw4; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="HOgJDWw4" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=8ve+K84xSNxeO4ivvNytWeMN5IvxW8DUwiSOEU3u4FQ=; b=HOgJDWw45QC2BBD1oG3llHgdSq j0dc64hqktQehbL2AilXDsZ/iouAm2AF6/ZfCMSIoAmhjzCL8l6nBxUm937+X/CJDNF27bBX6jUjV zGL74Q98BjMDqHteVRagXUm8IaSd6vjB/5Ke9rU8do0d+lumMSewEixVpXCzadVLf8K/J7foqatll felhDjW4zNfnvLyFduD+dowIdtEw9002GlCWtz24jROP5qwyHxSaAYiBkM919oG1KPJzvVzrMRftT Ht8nrehhWJMr2n4VkUJf4fouKJarI0WvUpWd4UHG1TId/3z2I0mDanPQBilBKTCAcERQh1Ezlt4Ri pTqXzxsg==; Received: from hch by bombadil.infradead.org with local (Exim 4.97.1 #2 (Red Hat Linux)) id 1sWgql-0000000GDVE-3EvN; Wed, 24 Jul 2024 18:36:31 +0000 Date: Wed, 24 Jul 2024 11:36:31 -0700 From: Christoph Hellwig To: Nirmal Patel 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: References: <20240724170040.5193-1-nirmal.patel@linux.intel.com> 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-Disposition: inline In-Reply-To: <20240724170040.5193-1-nirmal.patel@linux.intel.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html 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?