From: Jean-Philippe Brucker <jean-philippe@linaro.org>
To: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: "Tian, Kevin" <kevin.tian@intel.com>,
Raj Ashok <ashok.raj@intel.com>,
iommu@lists.linux-foundation.org,
LKML <linux-kernel@vger.kernel.org>,
Alex Williamson <alex.williamson@redhat.com>,
David Woodhouse <dwmw2@infradead.org>,
Jonathan Cameron <jic23@kernel.org>
Subject: Re: [PATCH 2/4] iommu: Add I/O ASID allocator
Date: Fri, 20 Sep 2019 18:33:27 +0200 [thread overview]
Message-ID: <20190920163327.GB1533866@lophozonia> (raw)
In-Reply-To: <1568849194-47874-3-git-send-email-jacob.jun.pan@linux.intel.com>
On Wed, Sep 18, 2019 at 04:26:32PM -0700, Jacob Pan wrote:
> From: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
>
> Some devices might support multiple DMA address spaces, in particular
> those that have the PCI PASID feature. PASID (Process Address Space ID)
> allows to share process address spaces with devices (SVA), partition a
> device into VM-assignable entities (VFIO mdev) or simply provide
> multiple DMA address space to kernel drivers. Add a global PASID
> allocator usable by different drivers at the same time. Name it I/O ASID
> to avoid confusion with ASIDs allocated by arch code, which are usually
> a separate ID space.
>
> The IOASID space is global. Each device can have its own PASID space,
> but by convention the IOMMU ended up having a global PASID space, so
> that with SVA, each mm_struct is associated to a single PASID.
>
> The allocator is primarily used by IOMMU subsystem but in rare occasions
> drivers would like to allocate PASIDs for devices that aren't managed by
> an IOMMU, using the same ID space as IOMMU.
>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
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next prev parent reply other threads:[~2019-09-20 16:33 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-18 23:26 [PATCH 0/4] User API for nested shared virtual address (SVA) Jacob Pan
2019-09-18 23:26 ` [PATCH 1/4] iommu: Introduce cache_invalidate API Jacob Pan
2019-09-20 16:32 ` Jean-Philippe Brucker
2019-09-18 23:26 ` [PATCH 2/4] iommu: Add I/O ASID allocator Jacob Pan
2019-09-19 6:30 ` kbuild test robot
2019-09-20 16:33 ` Jean-Philippe Brucker [this message]
2019-09-18 23:26 ` [PATCH 3/4] iommu/ioasid: Add custom allocators Jacob Pan
2019-09-20 16:35 ` Jean-Philippe Brucker
2019-09-21 17:42 ` Jacob Pan
2019-09-18 23:26 ` [PATCH 4/4] iommu: Introduce guest PASID bind function Jacob Pan
2019-09-20 16:38 ` Jean-Philippe Brucker
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