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From: Alyssa Rosenzweig <alyssa@collabora.com>
To: Boris Brezillon <boris.brezillon@collabora.com>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>,
	Will Deacon <will@kernel.org>,
	dri-devel@lists.freedesktop.org,
	Steven Price <steven.price@arm.com>,
	iommu@lists.linux-foundation.org,
	Rob Herring <robh+dt@kernel.org>,
	Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>,
	Robin Murphy <robin.murphy@arm.com>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 1/5] [RFC]iommu: Add a IOMMU_DEVONLY protection flag
Date: Fri, 1 Oct 2021 13:31:48 -0400	[thread overview]
Message-ID: <YVdGBLTApSccrr/6@maud> (raw)
In-Reply-To: <20211001143427.1564786-2-boris.brezillon@collabora.com>

> The IOMMU_DEVONLY flag allows the caller to flag a mappings backed by
> device-private buffers. That means other devices or CPUs are not
> expected to access the physical memory region pointed by the mapping,
> and the MMU driver can safely restrict the shareability domain to the
> device itself.
> 
> Will be used by the ARM MMU driver to flag Mali mappings accessed only
> by the GPU as Inner-shareable.
> 
> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
> ---
>  include/linux/iommu.h | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> index d2f3435e7d17..db14781b522f 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -31,6 +31,13 @@
>   * if the IOMMU page table format is equivalent.
>   */
>  #define IOMMU_PRIV	(1 << 5)
> +/*
> + * Mapping is only accessed by the device behind the iommu. That means other
> + * devices or CPUs are not expected to access this physical memory region,
> + * and the MMU driver can safely restrict the shareability domain to the
> + * device itself.
> + */
> +#define IOMMU_DEVONLY	(1 << 6)
>  
>  struct iommu_ops;
>  struct iommu_group;

This seems totally reasonable to me, but it is well-known that I'm not
on good terms with the iommu subsystem. Let's wait for Robin to NAK :-P
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

WARNING: multiple messages have this Message-ID (diff)
From: Alyssa Rosenzweig <alyssa@collabora.com>
To: Boris Brezillon <boris.brezillon@collabora.com>
Cc: Joerg Roedel <joro@8bytes.org>,
	iommu@lists.linux-foundation.org,
	Rob Herring <robh+dt@kernel.org>,
	Tomeu Vizoso <tomeu.vizoso@collabora.com>,
	Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>,
	Steven Price <steven.price@arm.com>,
	Robin Murphy <robin.murphy@arm.com>,
	Will Deacon <will@kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	dri-devel@lists.freedesktop.org
Subject: Re: [PATCH v2 1/5] [RFC]iommu: Add a IOMMU_DEVONLY protection flag
Date: Fri, 1 Oct 2021 13:31:48 -0400	[thread overview]
Message-ID: <YVdGBLTApSccrr/6@maud> (raw)
In-Reply-To: <20211001143427.1564786-2-boris.brezillon@collabora.com>

> The IOMMU_DEVONLY flag allows the caller to flag a mappings backed by
> device-private buffers. That means other devices or CPUs are not
> expected to access the physical memory region pointed by the mapping,
> and the MMU driver can safely restrict the shareability domain to the
> device itself.
> 
> Will be used by the ARM MMU driver to flag Mali mappings accessed only
> by the GPU as Inner-shareable.
> 
> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
> ---
>  include/linux/iommu.h | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> index d2f3435e7d17..db14781b522f 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -31,6 +31,13 @@
>   * if the IOMMU page table format is equivalent.
>   */
>  #define IOMMU_PRIV	(1 << 5)
> +/*
> + * Mapping is only accessed by the device behind the iommu. That means other
> + * devices or CPUs are not expected to access this physical memory region,
> + * and the MMU driver can safely restrict the shareability domain to the
> + * device itself.
> + */
> +#define IOMMU_DEVONLY	(1 << 6)
>  
>  struct iommu_ops;
>  struct iommu_group;

This seems totally reasonable to me, but it is well-known that I'm not
on good terms with the iommu subsystem. Let's wait for Robin to NAK :-P

WARNING: multiple messages have this Message-ID (diff)
From: Alyssa Rosenzweig <alyssa@collabora.com>
To: Boris Brezillon <boris.brezillon@collabora.com>
Cc: Joerg Roedel <joro@8bytes.org>,
	iommu@lists.linux-foundation.org,
	Rob Herring <robh+dt@kernel.org>,
	Tomeu Vizoso <tomeu.vizoso@collabora.com>,
	Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>,
	Steven Price <steven.price@arm.com>,
	Robin Murphy <robin.murphy@arm.com>,
	Will Deacon <will@kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	dri-devel@lists.freedesktop.org
Subject: Re: [PATCH v2 1/5] [RFC]iommu: Add a IOMMU_DEVONLY protection flag
Date: Fri, 1 Oct 2021 13:31:48 -0400	[thread overview]
Message-ID: <YVdGBLTApSccrr/6@maud> (raw)
In-Reply-To: <20211001143427.1564786-2-boris.brezillon@collabora.com>

> The IOMMU_DEVONLY flag allows the caller to flag a mappings backed by
> device-private buffers. That means other devices or CPUs are not
> expected to access the physical memory region pointed by the mapping,
> and the MMU driver can safely restrict the shareability domain to the
> device itself.
> 
> Will be used by the ARM MMU driver to flag Mali mappings accessed only
> by the GPU as Inner-shareable.
> 
> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
> ---
>  include/linux/iommu.h | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> index d2f3435e7d17..db14781b522f 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -31,6 +31,13 @@
>   * if the IOMMU page table format is equivalent.
>   */
>  #define IOMMU_PRIV	(1 << 5)
> +/*
> + * Mapping is only accessed by the device behind the iommu. That means other
> + * devices or CPUs are not expected to access this physical memory region,
> + * and the MMU driver can safely restrict the shareability domain to the
> + * device itself.
> + */
> +#define IOMMU_DEVONLY	(1 << 6)
>  
>  struct iommu_ops;
>  struct iommu_group;

This seems totally reasonable to me, but it is well-known that I'm not
on good terms with the iommu subsystem. Let's wait for Robin to NAK :-P

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

  reply	other threads:[~2021-10-01 17:31 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-01 14:34 [PATCH v2 0/5] drm/panfrost: Add extra GPU-usage flags Boris Brezillon
2021-10-01 14:34 ` Boris Brezillon
2021-10-01 14:34 ` Boris Brezillon
2021-10-01 14:34 ` [PATCH v2 1/5] [RFC]iommu: Add a IOMMU_DEVONLY protection flag Boris Brezillon
2021-10-01 14:34   ` Boris Brezillon
2021-10-01 14:34   ` Boris Brezillon
2021-10-01 17:31   ` Alyssa Rosenzweig [this message]
2021-10-01 17:31     ` Alyssa Rosenzweig
2021-10-01 17:31     ` Alyssa Rosenzweig
2021-10-18 10:25   ` Joerg Roedel
2021-10-18 10:25     ` Joerg Roedel
2021-10-18 10:25     ` Joerg Roedel
2021-10-18 12:03     ` Boris Brezillon
2021-10-18 12:03       ` Boris Brezillon
2021-10-18 12:03       ` Boris Brezillon
2021-10-01 14:34 ` [PATCH v2 2/5] [RFC]iommu/io-pgtable-arm: Take the DEVONLY flag into account on ARM_MALI_LPAE Boris Brezillon
2021-10-01 14:34   ` Boris Brezillon
2021-10-01 14:34   ` Boris Brezillon
2021-10-01 14:34 ` [PATCH v2 3/5] drm/panfrost: Add PANFROST_BO_NO{READ,WRITE} flags Boris Brezillon
2021-10-01 14:34   ` Boris Brezillon
2021-10-01 14:34   ` Boris Brezillon
2021-10-01 14:36   ` Boris Brezillon
2021-10-01 14:36     ` Boris Brezillon
2021-10-01 14:36     ` Boris Brezillon
2021-10-01 14:34 ` [PATCH v2 4/5] drm/panfrost: Add a PANFROST_BO_GPUONLY flag Boris Brezillon
2021-10-01 14:34   ` Boris Brezillon
2021-10-01 14:34   ` Boris Brezillon
2021-10-01 15:13   ` Steven Price
2021-10-01 15:13     ` Steven Price
2021-10-01 15:13     ` Steven Price
2021-10-01 16:22     ` Boris Brezillon
2021-10-01 16:22       ` Boris Brezillon
2021-10-01 16:22       ` Boris Brezillon
2021-10-01 17:30       ` Alyssa Rosenzweig
2021-10-01 17:30         ` Alyssa Rosenzweig
2021-10-01 17:30         ` Alyssa Rosenzweig
2021-10-01 14:34 ` [PATCH v2 5/5] drm/panfrost: Bump the driver version to 1.3 Boris Brezillon
2021-10-01 14:34   ` Boris Brezillon
2021-10-01 14:34   ` Boris Brezillon

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