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From: Stefano Stabellini <sstabellini@kernel.org>
To: Claire Chang <tientzu@chromium.org>
Cc: Rob Herring <robh+dt@kernel.org>,
	mpe@ellerman.id.au, Joerg Roedel <joro@8bytes.org>,
	Will Deacon <will@kernel.org>,
	Frank Rowand <frowand.list@gmail.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	boris.ostrovsky@oracle.com, jgross@suse.com,
	Christoph Hellwig <hch@lst.de>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	benh@kernel.crashing.org, paulus@samba.org,
	"list@263.net:IOMMU DRIVERS" <iommu@lists.linux-foundation.org>,
	sstabellini@kernel.org, Robin Murphy <robin.murphy@arm.com>,
	grant.likely@arm.com, xypron.glpk@gmx.de,
	Thierry Reding <treding@nvidia.com>,
	mingo@kernel.org, bauerman@linux.ibm.com, peterz@infradead.org,
	Greg KH <gregkh@linuxfoundation.org>,
	Saravana Kannan <saravanak@google.com>,
	"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
	heikki.krogerus@linux.intel.com,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Randy Dunlap <rdunlap@infradead.org>,
	Dan Williams <dan.j.williams@intel.com>,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>,
	linux-devicetree <devicetree@vger.kernel.org>,
	lkml <linux-kernel@vger.kernel.org>,
	linuxppc-dev@lists.ozlabs.org, xen-devel@lists.xenproject.org,
	Nicolas Boichat <drinkcat@chromium.org>,
	Jim Quinlan <james.quinlan@broadcom.com>,
	tfiga@chromium.org, bskeggs@redhat.com, bhelgaas@google.com,
	chris@chris-wilson.co.uk, daniel@ffwll.ch, airlied@linux.ie,
	dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org,
	jani.nikula@linux.intel.com, jxgao@google.com,
	joonas.lahtinen@linux.intel.com, linux-pci@vger.kernel.org,
	maarten.lankhorst@linux.intel.com, matthew.auld@intel.com,
	rodrigo.vivi@intel.com, thomas.hellstrom@linux.intel.com
Subject: Re: [PATCH v12 11/12] dt-bindings: of: Add restricted DMA pool
Date: Wed, 16 Jun 2021 17:09:29 -0700 (PDT)	[thread overview]
Message-ID: <alpine.DEB.2.21.2106161651290.24906@sstabellini-ThinkPad-T480s> (raw)
In-Reply-To: <20210616062157.953777-12-tientzu@chromium.org>

On Wed, 16 Jun 2021, Claire Chang wrote:
> Introduce the new compatible string, restricted-dma-pool, for restricted
> DMA. One can specify the address and length of the restricted DMA memory
> region by restricted-dma-pool in the reserved-memory node.
> 
> Signed-off-by: Claire Chang <tientzu@chromium.org>
> ---
>  .../reserved-memory/reserved-memory.txt       | 36 +++++++++++++++++--
>  1 file changed, 33 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
> index e8d3096d922c..46804f24df05 100644
> --- a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
> +++ b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
> @@ -51,6 +51,23 @@ compatible (optional) - standard definition
>            used as a shared pool of DMA buffers for a set of devices. It can
>            be used by an operating system to instantiate the necessary pool
>            management subsystem if necessary.
> +        - restricted-dma-pool: This indicates a region of memory meant to be
> +          used as a pool of restricted DMA buffers for a set of devices. The
> +          memory region would be the only region accessible to those devices.
> +          When using this, the no-map and reusable properties must not be set,
> +          so the operating system can create a virtual mapping that will be used
> +          for synchronization. The main purpose for restricted DMA is to
> +          mitigate the lack of DMA access control on systems without an IOMMU,
> +          which could result in the DMA accessing the system memory at
> +          unexpected times and/or unexpected addresses, possibly leading to data
> +          leakage or corruption. The feature on its own provides a basic level
> +          of protection against the DMA overwriting buffer contents at
> +          unexpected times. However, to protect against general data leakage and
> +          system memory corruption, the system needs to provide way to lock down
> +          the memory access, e.g., MPU. Note that since coherent allocation
> +          needs remapping, one must set up another device coherent pool by
> +          shared-dma-pool and use dma_alloc_from_dev_coherent instead for atomic
> +          coherent allocation.
>          - vendor specific string in the form <vendor>,[<device>-]<usage>
>  no-map (optional) - empty property
>      - Indicates the operating system must not create a virtual mapping
> @@ -85,10 +102,11 @@ memory-region-names (optional) - a list of names, one for each corresponding
>  
>  Example
>  -------
> -This example defines 3 contiguous regions are defined for Linux kernel:
> +This example defines 4 contiguous regions for Linux kernel:
>  one default of all device drivers (named linux,cma@72000000 and 64MiB in size),
> -one dedicated to the framebuffer device (named framebuffer@78000000, 8MiB), and
> -one for multimedia processing (named multimedia-memory@77000000, 64MiB).
> +one dedicated to the framebuffer device (named framebuffer@78000000, 8MiB),
> +one for multimedia processing (named multimedia-memory@77000000, 64MiB), and
> +one for restricted dma pool (named restricted_dma_reserved@0x50000000, 64MiB).
>  
>  / {
>  	#address-cells = <1>;
> @@ -120,6 +138,11 @@ one for multimedia processing (named multimedia-memory@77000000, 64MiB).
>  			compatible = "acme,multimedia-memory";
>  			reg = <0x77000000 0x4000000>;
>  		};
> +
> +		restricted_dma_reserved: restricted_dma_reserved {
> +			compatible = "restricted-dma-pool";
> +			reg = <0x50000000 0x4000000>;
> +		};
>  	};
>  
>  	/* ... */
> @@ -138,4 +161,11 @@ one for multimedia processing (named multimedia-memory@77000000, 64MiB).
>  		memory-region = <&multimedia_reserved>;
>  		/* ... */
>  	};
> +
> +	pcie_device: pcie_device@0,0 {
> +		reg = <0x83010000 0x0 0x00000000 0x0 0x00100000
> +		       0x83010000 0x0 0x00100000 0x0 0x00100000>;
> +		memory-region = <&restricted_dma_mem_reserved>;

Shouldn't it be &restricted_dma_reserved ?


WARNING: multiple messages have this Message-ID
From: Stefano Stabellini <sstabellini@kernel.org>
To: Claire Chang <tientzu@chromium.org>
Cc: heikki.krogerus@linux.intel.com,
	thomas.hellstrom@linux.intel.com, peterz@infradead.org,
	joonas.lahtinen@linux.intel.com, dri-devel@lists.freedesktop.org,
	chris@chris-wilson.co.uk, grant.likely@arm.com, paulus@samba.org,
	Frank Rowand <frowand.list@gmail.com>,
	mingo@kernel.org, Marek Szyprowski <m.szyprowski@samsung.com>,
	sstabellini@kernel.org, Saravana Kannan <saravanak@google.com>,
	Joerg Roedel <joro@8bytes.org>,
	"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
	Christoph Hellwig <hch@lst.de>,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>,
	bskeggs@redhat.com, linux-pci@vger.kernel.org,
	xen-devel@lists.xenproject.org,
	Thierry Reding <treding@nvidia.com>,
	intel-gfx@lists.freedesktop.org, matthew.auld@intel.com,
	linux-devicetree <devicetree@vger.kernel.org>,
	jxgao@google.com, daniel@ffwll.ch, Will Deacon <will@kernel.org>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	maarten.lankhorst@linux.intel.com, airlied@linux.ie,
	Dan Williams <dan.j.williams@intel.com>,
	linuxppc-dev@lists.ozlabs.org, jani.nikula@linux.intel.com,
	Rob Herring <robh+dt@kernel.org>,
	rodrigo.vivi@intel.com, bhelgaas@google.com,
	boris.ostrovsky@oracle.com,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	jgross@suse.com, Nicolas Boichat <drinkcat@chromium.org>,
	Greg KH <gregkh@linuxfoundation.org>,
	Randy Dunlap <rdunlap@infradead.org>,
	lkml <linux-kernel@vger.kernel.org>,
	tfiga@chromium.org,
	"list@263.net:IOMMU DRIVERS" <iommu@lists.linux-foundation.org>,
	Jim Quinlan <james.quinlan@broadcom.com>,
	xypron.glpk@gmx.de, Robin Murphy <robin.murphy@arm.com>,
	bauerman@linux.ibm.com
Subject: Re: [PATCH v12 11/12] dt-bindings: of: Add restricted DMA pool
Date: Wed, 16 Jun 2021 17:09:29 -0700 (PDT)	[thread overview]
Message-ID: <alpine.DEB.2.21.2106161651290.24906@sstabellini-ThinkPad-T480s> (raw)
In-Reply-To: <20210616062157.953777-12-tientzu@chromium.org>

On Wed, 16 Jun 2021, Claire Chang wrote:
> Introduce the new compatible string, restricted-dma-pool, for restricted
> DMA. One can specify the address and length of the restricted DMA memory
> region by restricted-dma-pool in the reserved-memory node.
> 
> Signed-off-by: Claire Chang <tientzu@chromium.org>
> ---
>  .../reserved-memory/reserved-memory.txt       | 36 +++++++++++++++++--
>  1 file changed, 33 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
> index e8d3096d922c..46804f24df05 100644
> --- a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
> +++ b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
> @@ -51,6 +51,23 @@ compatible (optional) - standard definition
>            used as a shared pool of DMA buffers for a set of devices. It can
>            be used by an operating system to instantiate the necessary pool
>            management subsystem if necessary.
> +        - restricted-dma-pool: This indicates a region of memory meant to be
> +          used as a pool of restricted DMA buffers for a set of devices. The
> +          memory region would be the only region accessible to those devices.
> +          When using this, the no-map and reusable properties must not be set,
> +          so the operating system can create a virtual mapping that will be used
> +          for synchronization. The main purpose for restricted DMA is to
> +          mitigate the lack of DMA access control on systems without an IOMMU,
> +          which could result in the DMA accessing the system memory at
> +          unexpected times and/or unexpected addresses, possibly leading to data
> +          leakage or corruption. The feature on its own provides a basic level
> +          of protection against the DMA overwriting buffer contents at
> +          unexpected times. However, to protect against general data leakage and
> +          system memory corruption, the system needs to provide way to lock down
> +          the memory access, e.g., MPU. Note that since coherent allocation
> +          needs remapping, one must set up another device coherent pool by
> +          shared-dma-pool and use dma_alloc_from_dev_coherent instead for atomic
> +          coherent allocation.
>          - vendor specific string in the form <vendor>,[<device>-]<usage>
>  no-map (optional) - empty property
>      - Indicates the operating system must not create a virtual mapping
> @@ -85,10 +102,11 @@ memory-region-names (optional) - a list of names, one for each corresponding
>  
>  Example
>  -------
> -This example defines 3 contiguous regions are defined for Linux kernel:
> +This example defines 4 contiguous regions for Linux kernel:
>  one default of all device drivers (named linux,cma@72000000 and 64MiB in size),
> -one dedicated to the framebuffer device (named framebuffer@78000000, 8MiB), and
> -one for multimedia processing (named multimedia-memory@77000000, 64MiB).
> +one dedicated to the framebuffer device (named framebuffer@78000000, 8MiB),
> +one for multimedia processing (named multimedia-memory@77000000, 64MiB), and
> +one for restricted dma pool (named restricted_dma_reserved@0x50000000, 64MiB).
>  
>  / {
>  	#address-cells = <1>;
> @@ -120,6 +138,11 @@ one for multimedia processing (named multimedia-memory@77000000, 64MiB).
>  			compatible = "acme,multimedia-memory";
>  			reg = <0x77000000 0x4000000>;
>  		};
> +
> +		restricted_dma_reserved: restricted_dma_reserved {
> +			compatible = "restricted-dma-pool";
> +			reg = <0x50000000 0x4000000>;
> +		};
>  	};
>  
>  	/* ... */
> @@ -138,4 +161,11 @@ one for multimedia processing (named multimedia-memory@77000000, 64MiB).
>  		memory-region = <&multimedia_reserved>;
>  		/* ... */
>  	};
> +
> +	pcie_device: pcie_device@0,0 {
> +		reg = <0x83010000 0x0 0x00000000 0x0 0x00100000
> +		       0x83010000 0x0 0x00100000 0x0 0x00100000>;
> +		memory-region = <&restricted_dma_mem_reserved>;

Shouldn't it be &restricted_dma_reserved ?


WARNING: multiple messages have this Message-ID
From: Stefano Stabellini <sstabellini@kernel.org>
To: Claire Chang <tientzu@chromium.org>
Cc: heikki.krogerus@linux.intel.com,
	thomas.hellstrom@linux.intel.com, peterz@infradead.org,
	benh@kernel.crashing.org, joonas.lahtinen@linux.intel.com,
	dri-devel@lists.freedesktop.org, chris@chris-wilson.co.uk,
	grant.likely@arm.com, paulus@samba.org,
	Frank Rowand <frowand.list@gmail.com>,
	mingo@kernel.org, sstabellini@kernel.org,
	Saravana Kannan <saravanak@google.com>,
	mpe@ellerman.id.au,
	"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
	Christoph Hellwig <hch@lst.de>,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>,
	bskeggs@redhat.com, linux-pci@vger.kernel.org,
	xen-devel@lists.xenproject.org,
	Thierry Reding <treding@nvidia.com>,
	intel-gfx@lists.freedesktop.org, matthew.auld@intel.com,
	linux-devicetree <devicetree@vger.kernel.org>,
	jxgao@google.com, daniel@ffwll.ch, Will Deacon <will@kernel.org>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	maarten.lankhorst@linux.intel.com, airlied@linux.ie,
	Dan Williams <dan.j.williams@intel.com>,
	linuxppc-dev@lists.ozlabs.org, jani.nikula@linux.intel.com,
	Rob Herring <robh+dt@kernel.org>,
	rodrigo.vivi@intel.com, bhelgaas@google.com,
	boris.ostrovsky@oracle.com,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	jgross@suse.com, Nicolas Boichat <drinkcat@chromium.org>,
	Greg KH <gregkh@linuxfoundation.org>,
	Randy Dunlap <rdunlap@infradead.org>,
	lkml <linux-kernel@vger.kernel.org>,
	"list@263.net:IOMMU DRIVERS" <iommu@lists.linux-foundation.org>,
	Jim Quinlan <james.quinlan@broadcom.com>,
	xypron.glpk@gmx.de, Robin Murphy <robin.murphy@arm.com>,
	bauerman@linux.ibm.com
Subject: Re: [PATCH v12 11/12] dt-bindings: of: Add restricted DMA pool
Date: Wed, 16 Jun 2021 17:09:29 -0700 (PDT)	[thread overview]
Message-ID: <alpine.DEB.2.21.2106161651290.24906@sstabellini-ThinkPad-T480s> (raw)
In-Reply-To: <20210616062157.953777-12-tientzu@chromium.org>

On Wed, 16 Jun 2021, Claire Chang wrote:
> Introduce the new compatible string, restricted-dma-pool, for restricted
> DMA. One can specify the address and length of the restricted DMA memory
> region by restricted-dma-pool in the reserved-memory node.
> 
> Signed-off-by: Claire Chang <tientzu@chromium.org>
> ---
>  .../reserved-memory/reserved-memory.txt       | 36 +++++++++++++++++--
>  1 file changed, 33 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
> index e8d3096d922c..46804f24df05 100644
> --- a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
> +++ b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
> @@ -51,6 +51,23 @@ compatible (optional) - standard definition
>            used as a shared pool of DMA buffers for a set of devices. It can
>            be used by an operating system to instantiate the necessary pool
>            management subsystem if necessary.
> +        - restricted-dma-pool: This indicates a region of memory meant to be
> +          used as a pool of restricted DMA buffers for a set of devices. The
> +          memory region would be the only region accessible to those devices.
> +          When using this, the no-map and reusable properties must not be set,
> +          so the operating system can create a virtual mapping that will be used
> +          for synchronization. The main purpose for restricted DMA is to
> +          mitigate the lack of DMA access control on systems without an IOMMU,
> +          which could result in the DMA accessing the system memory at
> +          unexpected times and/or unexpected addresses, possibly leading to data
> +          leakage or corruption. The feature on its own provides a basic level
> +          of protection against the DMA overwriting buffer contents at
> +          unexpected times. However, to protect against general data leakage and
> +          system memory corruption, the system needs to provide way to lock down
> +          the memory access, e.g., MPU. Note that since coherent allocation
> +          needs remapping, one must set up another device coherent pool by
> +          shared-dma-pool and use dma_alloc_from_dev_coherent instead for atomic
> +          coherent allocation.
>          - vendor specific string in the form <vendor>,[<device>-]<usage>
>  no-map (optional) - empty property
>      - Indicates the operating system must not create a virtual mapping
> @@ -85,10 +102,11 @@ memory-region-names (optional) - a list of names, one for each corresponding
>  
>  Example
>  -------
> -This example defines 3 contiguous regions are defined for Linux kernel:
> +This example defines 4 contiguous regions for Linux kernel:
>  one default of all device drivers (named linux,cma@72000000 and 64MiB in size),
> -one dedicated to the framebuffer device (named framebuffer@78000000, 8MiB), and
> -one for multimedia processing (named multimedia-memory@77000000, 64MiB).
> +one dedicated to the framebuffer device (named framebuffer@78000000, 8MiB),
> +one for multimedia processing (named multimedia-memory@77000000, 64MiB), and
> +one for restricted dma pool (named restricted_dma_reserved@0x50000000, 64MiB).
>  
>  / {
>  	#address-cells = <1>;
> @@ -120,6 +138,11 @@ one for multimedia processing (named multimedia-memory@77000000, 64MiB).
>  			compatible = "acme,multimedia-memory";
>  			reg = <0x77000000 0x4000000>;
>  		};
> +
> +		restricted_dma_reserved: restricted_dma_reserved {
> +			compatible = "restricted-dma-pool";
> +			reg = <0x50000000 0x4000000>;
> +		};
>  	};
>  
>  	/* ... */
> @@ -138,4 +161,11 @@ one for multimedia processing (named multimedia-memory@77000000, 64MiB).
>  		memory-region = <&multimedia_reserved>;
>  		/* ... */
>  	};
> +
> +	pcie_device: pcie_device@0,0 {
> +		reg = <0x83010000 0x0 0x00000000 0x0 0x00100000
> +		       0x83010000 0x0 0x00100000 0x0 0x00100000>;
> +		memory-region = <&restricted_dma_mem_reserved>;

Shouldn't it be &restricted_dma_reserved ?

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iommu mailing list
iommu@lists.linux-foundation.org
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WARNING: multiple messages have this Message-ID
From: Stefano Stabellini <sstabellini@kernel.org>
To: Claire Chang <tientzu@chromium.org>
Cc: heikki.krogerus@linux.intel.com,
	thomas.hellstrom@linux.intel.com, peterz@infradead.org,
	dri-devel@lists.freedesktop.org, chris@chris-wilson.co.uk,
	grant.likely@arm.com, paulus@samba.org,
	Frank Rowand <frowand.list@gmail.com>,
	mingo@kernel.org, Marek Szyprowski <m.szyprowski@samsung.com>,
	sstabellini@kernel.org, Saravana Kannan <saravanak@google.com>,
	mpe@ellerman.id.au, Joerg Roedel <joro@8bytes.org>,
	"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
	Christoph Hellwig <hch@lst.de>,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>,
	bskeggs@redhat.com, linux-pci@vger.kernel.org,
	xen-devel@lists.xenproject.org,
	Thierry Reding <treding@nvidia.com>,
	intel-gfx@lists.freedesktop.org, matthew.auld@intel.com,
	linux-devicetree <devicetree@vger.kernel.org>,
	jxgao@google.com, Will Deacon <will@kernel.org>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	airlied@linux.ie, Dan Williams <dan.j.williams@intel.com>,
	linuxppc-dev@lists.ozlabs.org, Rob Herring <robh+dt@kernel.org>,
	rodrigo.vivi@intel.com, bhelgaas@google.com,
	boris.ostrovsky@oracle.com,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	jgross@suse.com, Nicolas Boichat <drinkcat@chromium.org>,
	Greg KH <gregkh@linuxfoundation.org>,
	Randy Dunlap <rdunlap@infradead.org>,
	lkml <linux-kernel@vger.kernel.org>,
	tfiga@chromium.org,
	"list@263.net:IOMMU DRIVERS" <iommu@lists.linux-foundation.org>,
	Jim Quinlan <james.quinlan@broadcom.com>,
	xypron.glpk@gmx.de, Robin Murphy <robin.murphy@arm.com>,
	bauerman@linux.ibm.com
Subject: Re: [PATCH v12 11/12] dt-bindings: of: Add restricted DMA pool
Date: Wed, 16 Jun 2021 17:09:29 -0700 (PDT)	[thread overview]
Message-ID: <alpine.DEB.2.21.2106161651290.24906@sstabellini-ThinkPad-T480s> (raw)
In-Reply-To: <20210616062157.953777-12-tientzu@chromium.org>

On Wed, 16 Jun 2021, Claire Chang wrote:
> Introduce the new compatible string, restricted-dma-pool, for restricted
> DMA. One can specify the address and length of the restricted DMA memory
> region by restricted-dma-pool in the reserved-memory node.
> 
> Signed-off-by: Claire Chang <tientzu@chromium.org>
> ---
>  .../reserved-memory/reserved-memory.txt       | 36 +++++++++++++++++--
>  1 file changed, 33 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
> index e8d3096d922c..46804f24df05 100644
> --- a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
> +++ b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
> @@ -51,6 +51,23 @@ compatible (optional) - standard definition
>            used as a shared pool of DMA buffers for a set of devices. It can
>            be used by an operating system to instantiate the necessary pool
>            management subsystem if necessary.
> +        - restricted-dma-pool: This indicates a region of memory meant to be
> +          used as a pool of restricted DMA buffers for a set of devices. The
> +          memory region would be the only region accessible to those devices.
> +          When using this, the no-map and reusable properties must not be set,
> +          so the operating system can create a virtual mapping that will be used
> +          for synchronization. The main purpose for restricted DMA is to
> +          mitigate the lack of DMA access control on systems without an IOMMU,
> +          which could result in the DMA accessing the system memory at
> +          unexpected times and/or unexpected addresses, possibly leading to data
> +          leakage or corruption. The feature on its own provides a basic level
> +          of protection against the DMA overwriting buffer contents at
> +          unexpected times. However, to protect against general data leakage and
> +          system memory corruption, the system needs to provide way to lock down
> +          the memory access, e.g., MPU. Note that since coherent allocation
> +          needs remapping, one must set up another device coherent pool by
> +          shared-dma-pool and use dma_alloc_from_dev_coherent instead for atomic
> +          coherent allocation.
>          - vendor specific string in the form <vendor>,[<device>-]<usage>
>  no-map (optional) - empty property
>      - Indicates the operating system must not create a virtual mapping
> @@ -85,10 +102,11 @@ memory-region-names (optional) - a list of names, one for each corresponding
>  
>  Example
>  -------
> -This example defines 3 contiguous regions are defined for Linux kernel:
> +This example defines 4 contiguous regions for Linux kernel:
>  one default of all device drivers (named linux,cma@72000000 and 64MiB in size),
> -one dedicated to the framebuffer device (named framebuffer@78000000, 8MiB), and
> -one for multimedia processing (named multimedia-memory@77000000, 64MiB).
> +one dedicated to the framebuffer device (named framebuffer@78000000, 8MiB),
> +one for multimedia processing (named multimedia-memory@77000000, 64MiB), and
> +one for restricted dma pool (named restricted_dma_reserved@0x50000000, 64MiB).
>  
>  / {
>  	#address-cells = <1>;
> @@ -120,6 +138,11 @@ one for multimedia processing (named multimedia-memory@77000000, 64MiB).
>  			compatible = "acme,multimedia-memory";
>  			reg = <0x77000000 0x4000000>;
>  		};
> +
> +		restricted_dma_reserved: restricted_dma_reserved {
> +			compatible = "restricted-dma-pool";
> +			reg = <0x50000000 0x4000000>;
> +		};
>  	};
>  
>  	/* ... */
> @@ -138,4 +161,11 @@ one for multimedia processing (named multimedia-memory@77000000, 64MiB).
>  		memory-region = <&multimedia_reserved>;
>  		/* ... */
>  	};
> +
> +	pcie_device: pcie_device@0,0 {
> +		reg = <0x83010000 0x0 0x00000000 0x0 0x00100000
> +		       0x83010000 0x0 0x00100000 0x0 0x00100000>;
> +		memory-region = <&restricted_dma_mem_reserved>;

Shouldn't it be &restricted_dma_reserved ?


WARNING: multiple messages have this Message-ID
From: Stefano Stabellini <sstabellini@kernel.org>
To: Claire Chang <tientzu@chromium.org>
Cc: heikki.krogerus@linux.intel.com,
	thomas.hellstrom@linux.intel.com, peterz@infradead.org,
	benh@kernel.crashing.org, dri-devel@lists.freedesktop.org,
	chris@chris-wilson.co.uk, grant.likely@arm.com, paulus@samba.org,
	Frank Rowand <frowand.list@gmail.com>,
	mingo@kernel.org, Marek Szyprowski <m.szyprowski@samsung.com>,
	sstabellini@kernel.org, Saravana Kannan <saravanak@google.com>,
	mpe@ellerman.id.au, Joerg Roedel <joro@8bytes.org>,
	"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
	Christoph Hellwig <hch@lst.de>,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>,
	bskeggs@redhat.com, linux-pci@vger.kernel.org,
	xen-devel@lists.xenproject.org,
	Thierry Reding <treding@nvidia.com>,
	intel-gfx@lists.freedesktop.org, matthew.auld@intel.com,
	linux-devicetree <devicetree@vger.kernel.org>,
	jxgao@google.com, Will Deacon <will@kernel.org>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	airlied@linux.ie, Dan Williams <dan.j.williams@intel.com>,
	linuxppc-dev@lists.ozlabs.org, Rob Herring <robh+dt@kernel.org>,
	bhelgaas@google.com, boris.ostrovsky@oracle.com,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	jgross@suse.com, Nicolas Boichat <drinkcat@chromium.org>,
	Greg KH <gregkh@linuxfoundation.org>,
	Randy Dunlap <rdunlap@infradead.org>,
	lkml <linux-kernel@vger.kernel.org>,
	tfiga@chromium.org,
	"list@263.net:IOMMU DRIVERS" <iommu@lists.linux-foundation.org>,
	Jim Quinlan <james.quinlan@broadcom.com>,
	xypron.glpk@gmx.de, Robin Murphy <robin.murphy@arm.com>,
	bauerman@linux.ibm.com
Subject: Re: [Intel-gfx] [PATCH v12 11/12] dt-bindings: of: Add restricted DMA pool
Date: Wed, 16 Jun 2021 17:09:29 -0700 (PDT)	[thread overview]
Message-ID: <alpine.DEB.2.21.2106161651290.24906@sstabellini-ThinkPad-T480s> (raw)
In-Reply-To: <20210616062157.953777-12-tientzu@chromium.org>

On Wed, 16 Jun 2021, Claire Chang wrote:
> Introduce the new compatible string, restricted-dma-pool, for restricted
> DMA. One can specify the address and length of the restricted DMA memory
> region by restricted-dma-pool in the reserved-memory node.
> 
> Signed-off-by: Claire Chang <tientzu@chromium.org>
> ---
>  .../reserved-memory/reserved-memory.txt       | 36 +++++++++++++++++--
>  1 file changed, 33 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
> index e8d3096d922c..46804f24df05 100644
> --- a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
> +++ b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
> @@ -51,6 +51,23 @@ compatible (optional) - standard definition
>            used as a shared pool of DMA buffers for a set of devices. It can
>            be used by an operating system to instantiate the necessary pool
>            management subsystem if necessary.
> +        - restricted-dma-pool: This indicates a region of memory meant to be
> +          used as a pool of restricted DMA buffers for a set of devices. The
> +          memory region would be the only region accessible to those devices.
> +          When using this, the no-map and reusable properties must not be set,
> +          so the operating system can create a virtual mapping that will be used
> +          for synchronization. The main purpose for restricted DMA is to
> +          mitigate the lack of DMA access control on systems without an IOMMU,
> +          which could result in the DMA accessing the system memory at
> +          unexpected times and/or unexpected addresses, possibly leading to data
> +          leakage or corruption. The feature on its own provides a basic level
> +          of protection against the DMA overwriting buffer contents at
> +          unexpected times. However, to protect against general data leakage and
> +          system memory corruption, the system needs to provide way to lock down
> +          the memory access, e.g., MPU. Note that since coherent allocation
> +          needs remapping, one must set up another device coherent pool by
> +          shared-dma-pool and use dma_alloc_from_dev_coherent instead for atomic
> +          coherent allocation.
>          - vendor specific string in the form <vendor>,[<device>-]<usage>
>  no-map (optional) - empty property
>      - Indicates the operating system must not create a virtual mapping
> @@ -85,10 +102,11 @@ memory-region-names (optional) - a list of names, one for each corresponding
>  
>  Example
>  -------
> -This example defines 3 contiguous regions are defined for Linux kernel:
> +This example defines 4 contiguous regions for Linux kernel:
>  one default of all device drivers (named linux,cma@72000000 and 64MiB in size),
> -one dedicated to the framebuffer device (named framebuffer@78000000, 8MiB), and
> -one for multimedia processing (named multimedia-memory@77000000, 64MiB).
> +one dedicated to the framebuffer device (named framebuffer@78000000, 8MiB),
> +one for multimedia processing (named multimedia-memory@77000000, 64MiB), and
> +one for restricted dma pool (named restricted_dma_reserved@0x50000000, 64MiB).
>  
>  / {
>  	#address-cells = <1>;
> @@ -120,6 +138,11 @@ one for multimedia processing (named multimedia-memory@77000000, 64MiB).
>  			compatible = "acme,multimedia-memory";
>  			reg = <0x77000000 0x4000000>;
>  		};
> +
> +		restricted_dma_reserved: restricted_dma_reserved {
> +			compatible = "restricted-dma-pool";
> +			reg = <0x50000000 0x4000000>;
> +		};
>  	};
>  
>  	/* ... */
> @@ -138,4 +161,11 @@ one for multimedia processing (named multimedia-memory@77000000, 64MiB).
>  		memory-region = <&multimedia_reserved>;
>  		/* ... */
>  	};
> +
> +	pcie_device: pcie_device@0,0 {
> +		reg = <0x83010000 0x0 0x00000000 0x0 0x00100000
> +		       0x83010000 0x0 0x00100000 0x0 0x00100000>;
> +		memory-region = <&restricted_dma_mem_reserved>;

Shouldn't it be &restricted_dma_reserved ?

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  reply	other threads:[~2021-06-17  0:09 UTC|newest]

Thread overview: 97+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-16  6:21 [PATCH v12 00/12] Restricted DMA Claire Chang
2021-06-16  6:21 ` [Intel-gfx] " Claire Chang
2021-06-16  6:21 ` Claire Chang
2021-06-16  6:21 ` Claire Chang
2021-06-16  6:21 ` Claire Chang
2021-06-16  6:21 ` [PATCH v12 01/12] swiotlb: Refactor swiotlb init functions Claire Chang
2021-06-16  6:21   ` [Intel-gfx] " Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21 ` [PATCH v12 02/12] swiotlb: Refactor swiotlb_create_debugfs Claire Chang
2021-06-16  6:21   ` [Intel-gfx] " Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21 ` [PATCH v12 03/12] swiotlb: Set dev->dma_io_tlb_mem to the swiotlb pool used Claire Chang
2021-06-16  6:21   ` [Intel-gfx] " Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21 ` [PATCH v12 04/12] swiotlb: Update is_swiotlb_buffer to add a struct device argument Claire Chang
2021-06-16  6:21   ` [Intel-gfx] " Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21 ` [PATCH v12 05/12] swiotlb: Update is_swiotlb_active " Claire Chang
2021-06-16  6:21   ` [Intel-gfx] " Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21 ` [PATCH v12 06/12] swiotlb: Use is_swiotlb_force_bounce for swiotlb data bouncing Claire Chang
2021-06-16  6:21   ` [Intel-gfx] " Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  7:39   ` Christoph Hellwig
2021-06-16  7:39     ` [Intel-gfx] " Christoph Hellwig
2021-06-16  7:39     ` Christoph Hellwig
2021-06-16  7:39     ` Christoph Hellwig
2021-06-17  0:47   ` Stefano Stabellini
2021-06-17  0:47     ` Stefano Stabellini
2021-06-17  0:47     ` [Intel-gfx] " Stefano Stabellini
2021-06-17  0:47     ` Stefano Stabellini
2021-06-17  0:47     ` Stefano Stabellini
2021-06-17  0:47     ` Stefano Stabellini
2021-06-16  6:21 ` [PATCH v12 07/12] swiotlb: Move alloc_size to swiotlb_find_slots Claire Chang
2021-06-16  6:21   ` [Intel-gfx] " Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21 ` [PATCH v12 08/12] swiotlb: Refactor swiotlb_tbl_unmap_single Claire Chang
2021-06-16  6:21   ` [Intel-gfx] " Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21 ` [PATCH v12 09/12] swiotlb: Add restricted DMA alloc/free support Claire Chang
2021-06-16  6:21   ` [Intel-gfx] " Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  7:39   ` Christoph Hellwig
2021-06-16  7:39     ` [Intel-gfx] " Christoph Hellwig
2021-06-16  7:39     ` Christoph Hellwig
2021-06-16  7:39     ` Christoph Hellwig
2021-06-16  6:21 ` [PATCH v12 10/12] swiotlb: Add restricted DMA pool initialization Claire Chang
2021-06-16  6:21   ` [Intel-gfx] " Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21 ` [PATCH v12 11/12] dt-bindings: of: Add restricted DMA pool Claire Chang
2021-06-16  6:21   ` [Intel-gfx] " Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-17  0:09   ` Stefano Stabellini [this message]
2021-06-17  0:09     ` Stefano Stabellini
2021-06-17  0:09     ` [Intel-gfx] " Stefano Stabellini
2021-06-17  0:09     ` Stefano Stabellini
2021-06-17  0:09     ` Stefano Stabellini
2021-06-17  0:09     ` Stefano Stabellini
2021-06-16  6:21 ` [PATCH v12 12/12] of: Add plumbing for " Claire Chang
2021-06-16  6:21   ` [Intel-gfx] " Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  6:21   ` Claire Chang
2021-06-16  7:35 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for Restricted DMA Patchwork
2021-06-16 12:08 ` [PATCH v12 00/12] " Will Deacon
2021-06-16 12:08   ` [Intel-gfx] " Will Deacon
2021-06-16 12:08   ` Will Deacon
2021-06-16 12:08   ` Will Deacon
2021-06-16 12:08   ` Will Deacon
2021-06-17  6:40   ` Claire Chang
2021-06-17  6:40     ` Claire Chang
2021-06-17  6:40     ` [Intel-gfx] " Claire Chang
2021-06-17  6:40     ` Claire Chang
2021-06-17  6:40     ` Claire Chang
2021-06-17  6:40     ` Claire Chang

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