From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 6EA63611B for ; Tue, 1 Aug 2023 08:55:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E69C3C433C9; Tue, 1 Aug 2023 08:55:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1690880111; bh=9eJCKTqNMuD9Qzd4V6zbjbKNH9Wn22vwxY5UdngJOsA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=G2RNsx5poE4gfIohzHxNzgBThoQMTuMRj8TR1ONzG43Qx4zubbobawBjUKKwieY63 PYMuSGRF3htn76wjGsBiv+uirXuvL2iF5o1nlsyFnLTu8PLEVU6WgtomvfmyxI2jhg yMUOk4ovrZSItmxBkaWnPPqqcWFaAh0qxIbPlhrAxwfGAJeQ0KByKAJT4+HIr6Rzw7 tPlvYvD7be3Yk/+tJNuj64IFAFu5NVCjPvDVv6W/VQCwKFh8Z1MPIbi72FjuD3iaBE 6AWIG1ArxsPGsJb7nvUNPsRvKnA5Y7qf7zQiXKUPNE8WKmxbKiN8L9DNF/5G18uBd2 t7Nf7WXHCFwoQ== Date: Tue, 1 Aug 2023 09:55:05 +0100 From: Will Deacon To: wangwudi Cc: linux-arm-kernel@lists.infradead.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org, Rui Zhu , Robin Murphy , Joerg Roedel , Lu Baolu , Jason Gunthorpe , Yicong Yang , Tomas Krcka , Jean-Philippe Brucker , Nicolin Chen Subject: Re: [PATCH 1/1] Revert "iommu/arm-smmu-v3: Set TTL invalidation hint better" Message-ID: <20230801085504.GA26130@willie-the-truck> References: <1690784482-30028-1-git-send-email-wangwudi@hisilicon.com> Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1690784482-30028-1-git-send-email-wangwudi@hisilicon.com> User-Agent: Mutt/1.10.1 (2018-07-13) On Mon, Jul 31, 2023 at 02:21:22PM +0800, wangwudi wrote: > From: Rui Zhu > > This reverts commit 6833b8f2e19945a41e4d5efd8c6d9f4cae9a5b7d. > > This constraint violates the protocol. When tg is not 0 but ttl, scale, > and num are 0, the hardware reports the CERROR_IL gerror. In the > protocol, leaf is not a prerequisite for TTL. > > Cc: Will Deacon > Cc: Robin Murphy > Cc: Joerg Roedel > Cc: Lu Baolu > Cc: Jason Gunthorpe > Cc: Yicong Yang > Cc: Tomas Krcka > Cc: Jean-Philippe Brucker > Cc: Nicolin Chen > Cc: Rui Zhu > > Signed-off-by: Rui Zhu > --- > drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 9 ++------- > 1 file changed, 2 insertions(+), 7 deletions(-) > > diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c > index 9b0dc3505601..098e84cfa82f 100644 > --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c > +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c > @@ -1898,13 +1898,8 @@ static void __arm_smmu_tlb_inv_range(struct arm_smmu_cmdq_ent *cmd, > /* Convert page size of 12,14,16 (log2) to 1,2,3 */ > cmd->tlbi.tg = (tg - 10) / 2; > > - /* > - * Determine what level the granule is at. For non-leaf, io-pgtable > - * assumes .tlb_flush_walk can invalidate multiple levels at once, > - * so ignore the nominal last-level granule and leave TTL=0. > - */ > - if (cmd->tlbi.leaf) > - cmd->tlbi.ttl = 4 - ((ilog2(granule) - 3) / (tg - 3)); > + /* Determine what level the granule is at */ > + cmd->tlbi.ttl = 4 - ((ilog2(granule) - 3) / (tg - 3)); Doesn't this reintroduce the bug that 6833b8f2e199 tried to fix? afaict, we should only hit the problematic case of tg != 0 but ttl, scale and num all 0 if we're invalidating a single page, so shouldn't we just zap tg in that case, since it's not doing anything useful? I hesitate to say we should avoid range invalidation altogether for single-page invalidations because I think some errata workarounds might need that to work. Will