From: Will Deacon <will@kernel.org>
To: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Cc: Robin Murphy <robin.murphy@arm.com>,
Joerg Roedel <joro@8bytes.org>,
iommu@lists.linux-foundation.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
Doug Anderson <dianders@chromium.org>,
Krishna Reddy <vdumpa@nvidia.com>,
Thierry Reding <treding@nvidia.com>,
Tomasz Figa <tfiga@chromium.org>,
Bjorn Andersson <bjorn.andersson@linaro.org>
Subject: Re: [PATCHv4] iommu/arm-smmu: Optimize ->tlb_flush_walk() for qcom implementation
Date: Wed, 11 Aug 2021 11:30:12 +0100 [thread overview]
Message-ID: <20210811103011.GD4426@willie-the-truck> (raw)
In-Reply-To: <20210811060725.25221-1-saiprakash.ranjan@codeaurora.org>
On Wed, Aug 11, 2021 at 11:37:25AM +0530, Sai Prakash Ranjan wrote:
> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
> index f7da8953afbe..3904b598e0f9 100644
> --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
> @@ -327,9 +327,16 @@ static void arm_smmu_tlb_inv_range_s2(unsigned long iova, size_t size,
> static void arm_smmu_tlb_inv_walk_s1(unsigned long iova, size_t size,
> size_t granule, void *cookie)
> {
> - arm_smmu_tlb_inv_range_s1(iova, size, granule, cookie,
> - ARM_SMMU_CB_S1_TLBIVA);
> - arm_smmu_tlb_sync_context(cookie);
> + struct arm_smmu_domain *smmu_domain = cookie;
> + struct arm_smmu_cfg *cfg = &smmu_domain->cfg;
> +
> + if (cfg->flush_walk_prefer_tlbiasid) {
> + arm_smmu_tlb_inv_context_s1(cookie);
Hmm, this introduces an unconditional wmb() if tlbiasid is preferred. I
think that should be predicated on ARM_SMMU_FEAT_COHERENT_WALK like it is
for the by-VA ops. Worth doing as a separate patch.
> + } else {
> + arm_smmu_tlb_inv_range_s1(iova, size, granule, cookie,
> + ARM_SMMU_CB_S1_TLBIVA);
> + arm_smmu_tlb_sync_context(cookie);
> + }
> }
>
> static void arm_smmu_tlb_add_page_s1(struct iommu_iotlb_gather *gather,
> @@ -765,8 +772,10 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain,
> .iommu_dev = smmu->dev,
> };
>
> - if (!iommu_get_dma_strict(domain))
> + if (!iommu_get_dma_strict(domain)) {
> pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT;
> + cfg->flush_walk_prefer_tlbiasid = true;
This is going to interact badly with Robin's series to allow dynamic
transition to non-strict mode, as we don't have a mechanism to switch
over to the by-ASID behaviour. Yes, it should _work_, but it's ugly having
different TLBI behaviour just because of the how the domain became
non-strict.
Robin -- I think this originated from your idea at [1]. Any idea how to make
it work with your other series, or shall we drop this part for now and leave
the TLB invalidation behaviour the same for now?
Will
[1] https://lore.kernel.org/r/da62ff1c-9b49-34d3-69a1-1a674e4a30f7@arm.com
next prev parent reply other threads:[~2021-08-11 10:30 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-11 6:07 [PATCHv4] iommu/arm-smmu: Optimize ->tlb_flush_walk() for qcom implementation Sai Prakash Ranjan
2021-08-11 10:30 ` Will Deacon [this message]
2021-08-11 10:53 ` Sai Prakash Ranjan
2021-08-11 15:53 ` Robin Murphy
2021-08-11 16:06 ` Sai Prakash Ranjan
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210811103011.GD4426@willie-the-truck \
--to=will@kernel.org \
--cc=bjorn.andersson@linaro.org \
--cc=dianders@chromium.org \
--cc=iommu@lists.linux-foundation.org \
--cc=joro@8bytes.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=robin.murphy@arm.com \
--cc=saiprakash.ranjan@codeaurora.org \
--cc=tfiga@chromium.org \
--cc=treding@nvidia.com \
--cc=vdumpa@nvidia.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).