From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 95147C3A589 for ; Tue, 20 Aug 2019 15:58:29 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5D9D722DBF for ; Tue, 20 Aug 2019 15:58:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="nAlUc1Gk" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5D9D722DBF Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id 22093E34; Tue, 20 Aug 2019 15:58:29 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 7DA58E21 for ; Tue, 20 Aug 2019 15:58:28 +0000 (UTC) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 111BA89B for ; Tue, 20 Aug 2019 15:58:28 +0000 (UTC) Received: from willie-the-truck (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C6A1022CF7; Tue, 20 Aug 2019 15:58:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566316707; bh=dDXHA5bU4rB/VugoM/y+S4USn6RYgLcSxFjkdH7xqZg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=nAlUc1GkL0o2MiZB9ygu3+rAl7z9MXqOto5rybXrVg7AXjPeph788PYAKLdjE8BCj OfdOMzy2XmKYQMSg5+QiFfjJgbLZxxYicfz5+YMO5ZNMS4aPGYE3Fs6ouNnlYxPJ7d zGmDLsy1TXr2uf4OiOpILnZ92P5x388+5f7mUDjw= Date: Tue, 20 Aug 2019 16:58:24 +0100 From: Will Deacon To: Robin Murphy Subject: Re: [PATCH 4/4] iommu/io-pgtable-arm: Prepare for TTBR1 usage Message-ID: <20190820155823.ptn2rfvnmkd4v632@willie-the-truck> References: <6596469d5fa1e918145fdd4e6b1a3ad67f7cde2e.1566238530.git.robin.murphy@arm.com> <20190820103048.xacfbtn5o4wermhi@willie-the-truck> <469dc66a-2532-5f7f-cd8d-3fe13f6c279a@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <469dc66a-2532-5f7f-cd8d-3fe13f6c279a@arm.com> User-Agent: NeoMutt/20170113 (1.7.2) Cc: iommu@lists.linux-foundation.org, linux-arm-kernel@lists.infradead.org X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org On Tue, Aug 20, 2019 at 03:51:45PM +0100, Robin Murphy wrote: > On 20/08/2019 11:30, Will Deacon wrote: > > On Mon, Aug 19, 2019 at 07:19:31PM +0100, Robin Murphy wrote: > > > Now that callers are free to use a given table for TTBR1 if they wish > > > (all they need do is shift the provided attributes when constructing > > > their final TCR value), the only remaining impediment is the address > > > validation on map/unmap. The fact that the LPAE address space split is > > > symmetric makes this easy to accommodate - by simplifying the current > > > range checks into explicit tests that address bits above IAS are all > > > zero, it then follows straightforwardly to add the inverse test to > > > allow the all-ones case as well. > > > > > > Signed-off-by: Robin Murphy > > > --- > > > drivers/iommu/io-pgtable-arm.c | 7 ++++--- > > > 1 file changed, 4 insertions(+), 3 deletions(-) > > > > > > diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c > > > index 09cb20671fbb..f39c50356351 100644 > > > --- a/drivers/iommu/io-pgtable-arm.c > > > +++ b/drivers/iommu/io-pgtable-arm.c > > > @@ -475,13 +475,13 @@ static int arm_lpae_map(struct io_pgtable_ops *ops, unsigned long iova, > > > arm_lpae_iopte *ptep = data->pgd; > > > int ret, lvl = ARM_LPAE_START_LVL(data); > > > arm_lpae_iopte prot; > > > + long iaext = (long)iova >> data->iop.cfg.ias; > > > /* If no access, then nothing to do */ > > > if (!(iommu_prot & (IOMMU_READ | IOMMU_WRITE))) > > > return 0; > > > - if (WARN_ON(iova >= (1ULL << data->iop.cfg.ias) || > > > - paddr >= (1ULL << data->iop.cfg.oas))) > > > + if (WARN_ON((iaext && ~iaext) || paddr >> data->iop.cfg.oas)) > > > > I had to read that '&&' twice, but I see what you're doing now :) > > > > > return -ERANGE; > > > > This doesn't seem sufficient to prevent a mixture of TTBR1 and TTBR0 > > addresses from being mapped in the same TTBR. Perhaps we need a quirk for > > TTBR1, which could then take care of setting EPDx appropriately? > > Right, that's the one downside of going for the minimalist "io-pgtable > doesn't even have to know" approach. On reflection, though, in that paradigm > it should probably be the caller's responsibility to convert TTBR1 addresses > to preserve the "as if TTBR0" illusion anyway :/ Right, and I'd rather not push stuff into the caller for the common case. It's not exactly onerous to support this in io-pgtable. It's also why I'd still like to keep the EPDx in there, because the callers that care can rewrite the stuff, but at least we provided a default. > The advantage of not having a quirk is that it allows split address spaces > to fit more closely with the aux_domain idea, i.e. we could allocate and > initialise a domain without having to assume, or even care, whether it will > end up attached as a primary or aux domain. It *might* even be potentially > useful to have a domain attached to TTBR0 of one device's context and TTBR1 > of another's at the same time, although that's pretty niche. That sounds pretty theoretical to me at the moment. Will _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu