From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 4108513AC3 for ; Thu, 1 Jun 2023 16:43:38 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id DE9302F4; Thu, 1 Jun 2023 09:44:23 -0700 (PDT) Received: from e121345-lin.cambridge.arm.com (e121345-lin.cambridge.arm.com [10.1.196.40]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id B506A3F663; Thu, 1 Jun 2023 09:43:37 -0700 (PDT) From: Robin Murphy To: will@kernel.org Cc: joro@8bytes.org, jean-philippe@linaro.org, iommu@lists.linux.dev, linux-arm-kernel@lists.infradead.org Subject: [PATCH] iommu/arm-smmu-v3: Set TTL invalidation hint better Date: Thu, 1 Jun 2023 17:43:33 +0100 Message-Id: X-Mailer: git-send-email 2.39.2.101.g768bb238c484.dirty Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit When io-pgtable unmaps a whole table, rather than waste time walking it to find the leaf entries to invalidate exactly, it simply expects .tlb_flush_walk with nominal last-level granularity to invalidate any leaf entries at higher intermediate levels as well. This works fine with page-based invalidation, but with range commands we need to be careful with the TTL hint - unconditionally setting it based on the given level 3 granule means that an invalidation for a level 1 table would strictly not be required to affect level 2 block entries. It's easy to comply with the expected behaviour by simply not setting the TTL hint for non-leaf invalidations, so let's do that. Signed-off-by: Robin Murphy --- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 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 3fd83fb75722..4763e68cc1ab 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c @@ -1892,8 +1892,13 @@ 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 */ - cmd->tlbi.ttl = 4 - ((ilog2(granule) - 3) / (tg - 3)); + /* + * 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)); num_pages = size >> tg; } -- 2.39.2.101.g768bb238c484.dirty