From: Joerg Roedel <joro@8bytes.org>
To: Tom Murphy <tmurphy@arista.com>
Cc: iommu@lists.linux-foundation.org, murphyt7@tcd.ie,
Will Deacon <will.deacon@arm.com>,
Robin Murphy <robin.murphy@arm.com>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Kukjin Kim <kgene@kernel.org>,
Krzysztof Kozlowski <krzk@kernel.org>,
David Woodhouse <dwmw2@infradead.org>,
Andy Gross <andy.gross@linaro.org>,
David Brown <david.brown@linaro.org>,
Matthias Brugger <matthias.bgg@gmail.com>,
Rob Clark <robdclark@gmail.com>, Heiko Stuebner <heiko@sntech.de>,
Gerald Schaefer <gerald.schaefer@de.ibm.com>,
Thierry Reding <thierry.reding@gmail.com>,
Jonathan Hunter <jonathanh@nvidia.com>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-samsung-soc@vger.kernel.org, linux-arm-msm@vger.kernel.org,
linux-mediatek@lists.infradead.org,
linux-rockchip@lists.infradead.org, linux-s390@vger.kernel.org,
linux-tegra@vger.kernel.org
Subject: Re: [PATCH v3 0/4] iommu/amd: Convert the AMD iommu driver to the dma-iommu api
Date: Mon, 3 Jun 2019 12:51:58 +0200 [thread overview]
Message-ID: <20190603105158.GL12745@8bytes.org> (raw)
In-Reply-To: <20190506185207.31069-1-tmurphy@arista.com>
Hi Tom,
On Mon, May 06, 2019 at 07:52:02PM +0100, Tom Murphy wrote:
> Convert the AMD iommu driver to the dma-iommu api. Remove the iova
> handling and reserve region code from the AMD iommu driver.
Thank you for your work on this! I appreciate that much, but I am not
sure we are ready to make that move for the AMD and Intel IOMMU drivers
yet.
My main concern right now is that these changes will add a per-page
table lock into the fast-path for dma-mapping operations. There has been
much work in the past to remove all locking from these code-paths and
make it scalable on x86.
The dma-ops implementations in the x86 IOMMU drivers have the benefit
that they can call their page-table manipulation functions directly and
without locks, because they can make the necessary assumptions. The
IOMMU-API mapping/unmapping path can't make these assumptions because it
is also used for non-DMA-API use-cases.
So before we can move the AMD and Intel drivers to the generic DMA-API
implementation we need to solve this problem to not introduce new
scalability regressions.
Regards,
Joerg
WARNING: multiple messages have this Message-ID (diff)
From: Joerg Roedel <joro@8bytes.org>
To: Tom Murphy <tmurphy@arista.com>
Cc: Heiko Stuebner <heiko@sntech.de>,
Will Deacon <will.deacon@arm.com>,
David Brown <david.brown@linaro.org>,
Thierry Reding <thierry.reding@gmail.com>,
linux-s390@vger.kernel.org, linux-samsung-soc@vger.kernel.org,
iommu@lists.linux-foundation.org,
Krzysztof Kozlowski <krzk@kernel.org>,
Jonathan Hunter <jonathanh@nvidia.com>,
linux-rockchip@lists.infradead.org, Kukjin Kim <kgene@kernel.org>,
Gerald Schaefer <gerald.schaefer@de.ibm.com>,
Andy Gross <andy.gross@linaro.org>,
linux-tegra@vger.kernel.org, linux-arm-msm@vger.kernel.org,
linux-mediatek@lists.infradead.org,
Matthias Brugger <matthias.bgg@gmail.com>,
linux-arm-kernel@lists.infradead.org,
Robin Murphy <robin.murphy@arm.com>,
linux-kernel@vger.kernel.org, murphyt7@tcd.ie,
David Woodhouse <dwmw2@infradead.org>
Subject: Re: [PATCH v3 0/4] iommu/amd: Convert the AMD iommu driver to the dma-iommu api
Date: Mon, 3 Jun 2019 12:51:58 +0200 [thread overview]
Message-ID: <20190603105158.GL12745@8bytes.org> (raw)
In-Reply-To: <20190506185207.31069-1-tmurphy@arista.com>
Hi Tom,
On Mon, May 06, 2019 at 07:52:02PM +0100, Tom Murphy wrote:
> Convert the AMD iommu driver to the dma-iommu api. Remove the iova
> handling and reserve region code from the AMD iommu driver.
Thank you for your work on this! I appreciate that much, but I am not
sure we are ready to make that move for the AMD and Intel IOMMU drivers
yet.
My main concern right now is that these changes will add a per-page
table lock into the fast-path for dma-mapping operations. There has been
much work in the past to remove all locking from these code-paths and
make it scalable on x86.
The dma-ops implementations in the x86 IOMMU drivers have the benefit
that they can call their page-table manipulation functions directly and
without locks, because they can make the necessary assumptions. The
IOMMU-API mapping/unmapping path can't make these assumptions because it
is also used for non-DMA-API use-cases.
So before we can move the AMD and Intel drivers to the generic DMA-API
implementation we need to solve this problem to not introduce new
scalability regressions.
Regards,
Joerg
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
WARNING: multiple messages have this Message-ID (diff)
From: Joerg Roedel <joro@8bytes.org>
To: Tom Murphy <tmurphy@arista.com>
Cc: iommu@lists.linux-foundation.org, murphyt7@tcd.ie,
Will Deacon <will.deacon@arm.com>,
Robin Murphy <robin.murphy@arm.com>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Kukjin Kim <kgene@kernel.org>,
Krzysztof Kozlowski <krzk@kernel.org>,
David Woodhouse <dwmw2@infradead.org>,
Andy Gross <andy.gross@linaro.org>,
David Brown <david.brown@linaro.org>,
Matthias Brugger <matthias.bgg@gmail.com>,
Rob Clark <robdclark@gmail.com>, Heiko Stuebner <heiko@sntech.de>,
Gerald Schaefer <gerald.schaefer@de.ibm.com>,
Thierry Reding <thierry.reding@gmail.com>,
Jonathan Hunter <jonathanh@nvidia.com>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-samsung-soc@vger.kernel.org, linux-arm-msm@vger.kernel.org,
linux-mediatek@lists.infradead.org
Subject: Re: [PATCH v3 0/4] iommu/amd: Convert the AMD iommu driver to the dma-iommu api
Date: Mon, 3 Jun 2019 12:51:58 +0200 [thread overview]
Message-ID: <20190603105158.GL12745@8bytes.org> (raw)
In-Reply-To: <20190506185207.31069-1-tmurphy@arista.com>
Hi Tom,
On Mon, May 06, 2019 at 07:52:02PM +0100, Tom Murphy wrote:
> Convert the AMD iommu driver to the dma-iommu api. Remove the iova
> handling and reserve region code from the AMD iommu driver.
Thank you for your work on this! I appreciate that much, but I am not
sure we are ready to make that move for the AMD and Intel IOMMU drivers
yet.
My main concern right now is that these changes will add a per-page
table lock into the fast-path for dma-mapping operations. There has been
much work in the past to remove all locking from these code-paths and
make it scalable on x86.
The dma-ops implementations in the x86 IOMMU drivers have the benefit
that they can call their page-table manipulation functions directly and
without locks, because they can make the necessary assumptions. The
IOMMU-API mapping/unmapping path can't make these assumptions because it
is also used for non-DMA-API use-cases.
So before we can move the AMD and Intel drivers to the generic DMA-API
implementation we need to solve this problem to not introduce new
scalability regressions.
Regards,
Joerg
WARNING: multiple messages have this Message-ID (diff)
From: Joerg Roedel <joro@8bytes.org>
To: Tom Murphy <tmurphy@arista.com>
Cc: Heiko Stuebner <heiko@sntech.de>,
Will Deacon <will.deacon@arm.com>,
David Brown <david.brown@linaro.org>,
Thierry Reding <thierry.reding@gmail.com>,
Marek Szyprowski <m.szyprowski@samsung.com>,
linux-s390@vger.kernel.org, linux-samsung-soc@vger.kernel.org,
iommu@lists.linux-foundation.org,
Krzysztof Kozlowski <krzk@kernel.org>,
Jonathan Hunter <jonathanh@nvidia.com>,
linux-rockchip@lists.infradead.org, Kukjin Kim <kgene@kernel.org>,
Gerald Schaefer <gerald.schaefer@de.ibm.com>,
Andy Gross <andy.gross@linaro.org>,
linux-tegra@vger.kernel.org, linux-arm-msm@vger.kernel.org,
linux-mediatek@lists.infradead.org,
Matthias Brugger <matthias.bgg@gmail.com>,
linux-arm-kernel@lists.infradead.org,
Robin Murphy <robin.murphy@arm.com>,
linux-kernel@vger.kernel.org, murphyt7@tcd.ie,
Rob Clark <robdclark@gmail.com>,
David Woodhouse <dwmw2@infradead.org>
Subject: Re: [PATCH v3 0/4] iommu/amd: Convert the AMD iommu driver to the dma-iommu api
Date: Mon, 3 Jun 2019 12:51:58 +0200 [thread overview]
Message-ID: <20190603105158.GL12745@8bytes.org> (raw)
In-Reply-To: <20190506185207.31069-1-tmurphy@arista.com>
Hi Tom,
On Mon, May 06, 2019 at 07:52:02PM +0100, Tom Murphy wrote:
> Convert the AMD iommu driver to the dma-iommu api. Remove the iova
> handling and reserve region code from the AMD iommu driver.
Thank you for your work on this! I appreciate that much, but I am not
sure we are ready to make that move for the AMD and Intel IOMMU drivers
yet.
My main concern right now is that these changes will add a per-page
table lock into the fast-path for dma-mapping operations. There has been
much work in the past to remove all locking from these code-paths and
make it scalable on x86.
The dma-ops implementations in the x86 IOMMU drivers have the benefit
that they can call their page-table manipulation functions directly and
without locks, because they can make the necessary assumptions. The
IOMMU-API mapping/unmapping path can't make these assumptions because it
is also used for non-DMA-API use-cases.
So before we can move the AMD and Intel drivers to the generic DMA-API
implementation we need to solve this problem to not introduce new
scalability regressions.
Regards,
Joerg
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2019-06-03 10:52 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-06 18:52 [PATCH v3 0/4] iommu/amd: Convert the AMD iommu driver to the dma-iommu api Tom Murphy via iommu
2019-05-06 18:52 ` Tom Murphy
2019-05-06 18:52 ` Tom Murphy via iommu
2019-05-06 18:52 ` Tom Murphy
[not found] ` <20190506185207.31069-1-tmurphy-nzgTgzXrdUbQT0dZR+AlfA@public.gmane.org>
2019-05-06 18:52 ` [PATCH v3 1/4] iommu: Add gfp parameter to iommu_ops::map Tom Murphy via iommu
2019-05-06 18:52 ` Tom Murphy
2019-05-06 18:52 ` Tom Murphy via iommu
2019-05-06 18:52 ` Tom Murphy
2019-06-04 18:11 ` Robin Murphy
2019-06-04 18:11 ` Robin Murphy
2019-06-04 18:11 ` Robin Murphy
2019-06-04 18:11 ` Robin Murphy
2019-06-04 20:55 ` Tom Murphy
2019-06-04 20:55 ` Tom Murphy
2019-06-04 20:55 ` Tom Murphy
2019-06-04 20:55 ` Tom Murphy via iommu
2019-06-04 21:24 ` Rob Clark
2019-06-04 21:24 ` Rob Clark
2019-06-04 21:24 ` Rob Clark
2019-06-04 21:24 ` Rob Clark
2019-06-04 21:24 ` Rob Clark
2019-06-05 5:50 ` Christoph Hellwig
2019-06-05 5:50 ` Christoph Hellwig
2019-06-05 5:50 ` Christoph Hellwig
2019-06-05 5:50 ` Christoph Hellwig
2019-05-06 18:52 ` [PATCH v3 3/4] iommu/dma-iommu: Use the dev->coherent_dma_mask Tom Murphy via iommu
2019-05-06 18:52 ` Tom Murphy
2019-05-06 18:52 ` Tom Murphy via iommu
2019-05-06 18:52 ` Tom Murphy
2019-05-06 18:52 ` [PATCH v3 2/4] iommu/dma-iommu: Handle deferred devices Tom Murphy
2019-05-06 18:52 ` Tom Murphy
2019-05-06 18:52 ` Tom Murphy via iommu
2019-05-06 18:52 ` Tom Murphy
2019-05-07 6:40 ` Christoph Hellwig
2019-05-07 6:40 ` Christoph Hellwig
2019-05-07 6:40 ` Christoph Hellwig
2019-05-07 6:40 ` Christoph Hellwig
2019-05-15 12:46 ` Tom Murphy
2019-05-15 12:46 ` Tom Murphy
2019-05-15 12:46 ` Tom Murphy
2019-05-15 12:46 ` Tom Murphy
2019-05-15 12:46 ` Tom Murphy via iommu
2019-05-06 18:52 ` [PATCH v3 4/4] iommu/amd: Convert AMD iommu driver to the dma-iommu api Tom Murphy
2019-05-06 18:52 ` Tom Murphy
2019-05-06 18:52 ` Tom Murphy via iommu
2019-05-06 18:52 ` Tom Murphy
2019-06-03 10:51 ` Joerg Roedel [this message]
2019-06-03 10:51 ` [PATCH v3 0/4] iommu/amd: Convert the " Joerg Roedel
2019-06-03 10:51 ` Joerg Roedel
2019-06-03 10:51 ` Joerg Roedel
2019-06-03 11:27 ` Tom Murphy
2019-06-03 11:27 ` Tom Murphy
2019-06-03 11:27 ` Tom Murphy
2019-06-03 11:27 ` Tom Murphy via iommu
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