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From: Will Deacon <will@kernel.org>
To: Rob Clark <robdclark@gmail.com>
Cc: Konrad Dybcio <konrad.dybcio@somainline.org>,
	~postmarketos/upstreaming@lists.sr.ht,
	linux-arm-msm <linux-arm-msm@vger.kernel.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	"moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" 
	<linux-arm-kernel@lists.infradead.org>,
	"list@263.net:IOMMU DRIVERS <iommu@lists.linux-foundation.org>,
	Joerg Roedel <joro@8bytes.org>,"
	<iommu@lists.linux-foundation.org>,
	Martin Botka <martin.botka@somainline.org>,
	AngeloGioacchino Del Regno 
	<angelogioacchino.delregno@somainline.org>,
	Marijn Suijten <marijn.suijten@somainline.org>,
	jamipkettunen@somainline.org, Andy Gross <agross@kernel.org>,
	Joerg Roedel <joro@8bytes.org>, Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Robin Murphy <robin.murphy@arm.com>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
	<devicetree@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/6] iommu/qcom: Use the asid read from device-tree if specified
Date: Tue, 31 May 2022 17:19:11 +0100	[thread overview]
Message-ID: <20220531161910.GE25502@willie-the-truck> (raw)
In-Reply-To: <CAF6AEGsWsHfQZnszG=NgP0BufxO-DP4LwvsAYkrz2wRhcJuOXw@mail.gmail.com>

On Tue, May 31, 2022 at 09:15:22AM -0700, Rob Clark wrote:
> On Tue, May 31, 2022 at 8:46 AM Will Deacon <will@kernel.org> wrote:
> >
> > On Fri, May 27, 2022 at 11:28:56PM +0200, Konrad Dybcio wrote:
> > > From: AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org>
> > >
> > > As specified in this driver, the context banks are 0x1000 apart.
> > > Problem is that sometimes the context number (our asid) does not
> > > match this logic and we end up using the wrong one: this starts
> > > being a problem in the case that we need to send TZ commands
> > > to do anything on a specific context.
> >
> > I don't understand this. The ASID is a software construct, so it shouldn't
> > matter what we use. If it does matter, then please can you explain why? The
> > fact that the context banks are 0x1000 apart seems unrelated.
> 
> I think the connection is that mapping from ctx bank to ASID is 1:1

But in what sense? How is the ASID used beyond a tag in the TLB? The commit
message hints at "TZ commands" being a problem.

I'm not doubting that this is needed to make the thing work, I just don't
understand why.

Will

WARNING: multiple messages have this Message-ID (diff)
From: Will Deacon <will@kernel.org>
To: Rob Clark <robdclark@gmail.com>
Cc: "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
	<devicetree@vger.kernel.org>,
	linux-arm-msm <linux-arm-msm@vger.kernel.org>,
	Konrad Dybcio <konrad.dybcio@somainline.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	jamipkettunen@somainline.org, Rob Herring <robh+dt@kernel.org>,
	"list@263.net:IOMMU DRIVERS <iommu@lists.linux-foundation.org>,
	Joerg Roedel <joro@8bytes.org>,
	" <iommu@lists.linux-foundation.org>,
	Andy Gross <agross@kernel.org>,
	Martin Botka <martin.botka@somainline.org>,
	~postmarketos/upstreaming@lists.sr.ht,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	AngeloGioacchino Del Regno
	<angelogioacchino.delregno@somainline.org>,
	Marijn Suijten <marijn.suijten@somainline.org>,
	Robin Murphy <robin.murphy@arm.com>,
	"moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE"
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 1/6] iommu/qcom: Use the asid read from device-tree if specified
Date: Tue, 31 May 2022 17:19:11 +0100	[thread overview]
Message-ID: <20220531161910.GE25502@willie-the-truck> (raw)
In-Reply-To: <CAF6AEGsWsHfQZnszG=NgP0BufxO-DP4LwvsAYkrz2wRhcJuOXw@mail.gmail.com>

On Tue, May 31, 2022 at 09:15:22AM -0700, Rob Clark wrote:
> On Tue, May 31, 2022 at 8:46 AM Will Deacon <will@kernel.org> wrote:
> >
> > On Fri, May 27, 2022 at 11:28:56PM +0200, Konrad Dybcio wrote:
> > > From: AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org>
> > >
> > > As specified in this driver, the context banks are 0x1000 apart.
> > > Problem is that sometimes the context number (our asid) does not
> > > match this logic and we end up using the wrong one: this starts
> > > being a problem in the case that we need to send TZ commands
> > > to do anything on a specific context.
> >
> > I don't understand this. The ASID is a software construct, so it shouldn't
> > matter what we use. If it does matter, then please can you explain why? The
> > fact that the context banks are 0x1000 apart seems unrelated.
> 
> I think the connection is that mapping from ctx bank to ASID is 1:1

But in what sense? How is the ASID used beyond a tag in the TLB? The commit
message hints at "TZ commands" being a problem.

I'm not doubting that this is needed to make the thing work, I just don't
understand why.

Will
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

WARNING: multiple messages have this Message-ID (diff)
From: Will Deacon <will@kernel.org>
To: Rob Clark <robdclark@gmail.com>
Cc: Konrad Dybcio <konrad.dybcio@somainline.org>,
	~postmarketos/upstreaming@lists.sr.ht,
	linux-arm-msm <linux-arm-msm@vger.kernel.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	"moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE"
	<linux-arm-kernel@lists.infradead.org>,
	"list@263.net:IOMMU DRIVERS <iommu@lists.linux-foundation.org>,
	Joerg Roedel <joro@8bytes.org>,"
	<iommu@lists.linux-foundation.org>,
	Martin Botka <martin.botka@somainline.org>,
	AngeloGioacchino Del Regno
	<angelogioacchino.delregno@somainline.org>,
	Marijn Suijten <marijn.suijten@somainline.org>,
	jamipkettunen@somainline.org, Andy Gross <agross@kernel.org>,
	Joerg Roedel <joro@8bytes.org>, Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Robin Murphy <robin.murphy@arm.com>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
	<devicetree@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/6] iommu/qcom: Use the asid read from device-tree if specified
Date: Tue, 31 May 2022 17:19:11 +0100	[thread overview]
Message-ID: <20220531161910.GE25502@willie-the-truck> (raw)
In-Reply-To: <CAF6AEGsWsHfQZnszG=NgP0BufxO-DP4LwvsAYkrz2wRhcJuOXw@mail.gmail.com>

On Tue, May 31, 2022 at 09:15:22AM -0700, Rob Clark wrote:
> On Tue, May 31, 2022 at 8:46 AM Will Deacon <will@kernel.org> wrote:
> >
> > On Fri, May 27, 2022 at 11:28:56PM +0200, Konrad Dybcio wrote:
> > > From: AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org>
> > >
> > > As specified in this driver, the context banks are 0x1000 apart.
> > > Problem is that sometimes the context number (our asid) does not
> > > match this logic and we end up using the wrong one: this starts
> > > being a problem in the case that we need to send TZ commands
> > > to do anything on a specific context.
> >
> > I don't understand this. The ASID is a software construct, so it shouldn't
> > matter what we use. If it does matter, then please can you explain why? The
> > fact that the context banks are 0x1000 apart seems unrelated.
> 
> I think the connection is that mapping from ctx bank to ASID is 1:1

But in what sense? How is the ASID used beyond a tag in the TLB? The commit
message hints at "TZ commands" being a problem.

I'm not doubting that this is needed to make the thing work, I just don't
understand why.

Will

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2022-05-31 16:19 UTC|newest]

Thread overview: 71+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-27 21:28 [PATCH 0/6] Fix and extend Qualcomm IOMMU support Konrad Dybcio
2022-05-27 21:28 ` Konrad Dybcio
2022-05-27 21:28 ` Konrad Dybcio
2022-05-27 21:28 ` [PATCH 1/6] iommu/qcom: Use the asid read from device-tree if specified Konrad Dybcio
2022-05-27 21:28   ` Konrad Dybcio
2022-05-27 21:28   ` Konrad Dybcio
2022-05-31 15:46   ` Will Deacon
2022-05-31 15:46     ` Will Deacon
2022-05-31 15:46     ` Will Deacon
2022-05-31 16:15     ` Rob Clark
2022-05-31 16:15       ` Rob Clark
2022-05-31 16:15       ` Rob Clark
2022-05-31 16:19       ` Will Deacon [this message]
2022-05-31 16:19         ` Will Deacon
2022-05-31 16:19         ` Will Deacon
2022-05-31 20:57         ` Rob Clark
2022-05-31 20:57           ` Rob Clark
2022-05-31 20:57           ` Rob Clark
2022-06-03 18:03           ` Konrad Dybcio
2022-06-03 18:03             ` Konrad Dybcio
2022-06-03 18:03             ` Konrad Dybcio
2022-06-08 10:25             ` AngeloGioacchino Del Regno
2022-06-08 10:25               ` AngeloGioacchino Del Regno
2022-06-08 10:25               ` AngeloGioacchino Del Regno
2022-05-27 21:28 ` [PATCH 2/6] iommu/qcom: Write TCR before TTBRs to fix ASID access behavior Konrad Dybcio
2022-05-27 21:28   ` Konrad Dybcio
2022-05-27 21:28   ` Konrad Dybcio
2022-05-31 15:55   ` Will Deacon
2022-05-31 15:55     ` Will Deacon
2022-05-31 15:55     ` Will Deacon
2022-05-31 16:26     ` Robin Murphy
2022-05-31 16:26       ` Robin Murphy
2022-05-31 16:26       ` Robin Murphy
2022-06-05 22:06     ` Marijn Suijten
2022-06-05 22:06       ` Marijn Suijten
2022-06-05 22:06       ` Marijn Suijten
2022-06-08 10:27       ` AngeloGioacchino Del Regno
2022-06-08 10:27         ` AngeloGioacchino Del Regno
2022-06-08 10:27         ` AngeloGioacchino Del Regno
2022-06-08 10:54         ` Robin Murphy
2022-06-08 10:54           ` Robin Murphy
2022-06-08 10:54           ` Robin Murphy
2022-06-08 11:03           ` AngeloGioacchino Del Regno
2022-06-08 11:03             ` AngeloGioacchino Del Regno
2022-06-08 11:03             ` AngeloGioacchino Del Regno
2022-05-27 21:28 ` [PATCH 3/6] iommu/qcom: Properly reset the IOMMU context Konrad Dybcio
2022-05-27 21:28   ` Konrad Dybcio
2022-05-27 21:28   ` Konrad Dybcio
2022-05-27 21:28 ` [PATCH 4/6] iommu/qcom: Add support for AArch64 IOMMU pagetables Konrad Dybcio
2022-05-27 21:28   ` Konrad Dybcio
2022-05-27 21:28   ` Konrad Dybcio
2022-05-28  2:03   ` kernel test robot
2022-05-28  2:03     ` kernel test robot
2022-05-28  2:03     ` kernel test robot
2022-06-02 14:17   ` Rob Herring
2022-06-02 14:17     ` Rob Herring
2022-06-02 14:17     ` Rob Herring
2022-05-27 21:29 ` [PATCH 5/6] iommu/qcom: Index contexts by asid number to allow asid 0 Konrad Dybcio
2022-05-27 21:29   ` Konrad Dybcio
2022-05-27 21:29   ` Konrad Dybcio
2022-06-03 15:14   ` Brian Masney
2022-06-03 15:14     ` Brian Masney
2022-06-03 15:14     ` Brian Masney
2022-05-27 21:29 ` [PATCH 6/6] iommu/qcom: Add support for QCIOMMUv2 and QCIOMMU-500 secured contexts Konrad Dybcio
2022-05-27 21:29   ` Konrad Dybcio
2022-05-27 21:29   ` Konrad Dybcio
  -- strict thread matches above, loose matches on Subject: below --
2019-09-26 12:05 [PATCH 0/6] Add support for QCOM IOMMU v2 and 500 kholk11
2019-09-26 12:05 ` [PATCH 1/6] iommu/qcom: Use the asid read from device-tree if specified kholk11
2019-09-26 12:05   ` kholk11
2019-09-26 20:06   ` Rob Clark
2019-09-26 20:06     ` Rob Clark
2019-09-26 20:06     ` Rob Clark

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