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From: David Marchand <david.marchand@redhat.com>
To: Nithin Dabilpuram <ndabilpuram@marvell.com>
Cc: "Burakov, Anatoly" <anatoly.burakov@intel.com>,
	David Christensen <drc@linux.vnet.ibm.com>,
	 Jerin Jacob Kollanukkaran <jerinj@marvell.com>,
	dev <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH v8 0/3] fix issue with partial DMA unmap
Date: Mon, 1 Mar 2021 13:13:32 +0100
Message-ID: <CAJFAV8xSKLkoJTbANeORbiRd1PbNo9QNEY5iMtkP5MhkESX+bw@mail.gmail.com> (raw)
In-Reply-To: <20210115073243.7025-1-ndabilpuram@marvell.com>

On Fri, Jan 15, 2021 at 8:33 AM Nithin Dabilpuram
<ndabilpuram@marvell.com> wrote:
>
> Partial DMA unmap is not supported by VFIO type1 IOMMU
> in Linux. Though the return value is zero, the returned
> DMA unmap size is not same as expected size.
> So add test case and fix to both heap triggered DMA
> mapping and user triggered DMA mapping/unmapping.
>
> Refer vfio_dma_do_unmap() in drivers/vfio/vfio_iommu_type1.c
> Snippet of comment is below.
>
>         /*
>          * vfio-iommu-type1 (v1) - User mappings were coalesced together to
>          * avoid tracking individual mappings.  This means that the granularity
>          * of the original mapping was lost and the user was allowed to attempt
>          * to unmap any range.  Depending on the contiguousness of physical
>          * memory and page sizes supported by the IOMMU, arbitrary unmaps may
>          * or may not have worked.  We only guaranteed unmap granularity
>          * matching the original mapping; even though it was untracked here,
>          * the original mappings are reflected in IOMMU mappings.  This
>          * resulted in a couple unusual behaviors.  First, if a range is not
>          * able to be unmapped, ex. a set of 4k pages that was mapped as a
>          * 2M hugepage into the IOMMU, the unmap ioctl returns success but with
>          * a zero sized unmap.  Also, if an unmap request overlaps the first
>          * address of a hugepage, the IOMMU will unmap the entire hugepage.
>          * This also returns success and the returned unmap size reflects the
>          * actual size unmapped.
>
>          * We attempt to maintain compatibility with this "v1" interface, but
>          * we take control out of the hands of the IOMMU.  Therefore, an unmap
>          * request offset from the beginning of the original mapping will
>          * return success with zero sized unmap.  And an unmap request covering
>          * the first iova of mapping will unmap the entire range.
>
> This behavior can be verified by using first patch and add return check for
> dma_unmap.size != len in vfio_type1_dma_mem_map()

Series applied, thanks.


-- 
David Marchand


      parent reply	other threads:[~2021-03-01 12:13 UTC|newest]

Thread overview: 81+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-12  8:11 [dpdk-dev] [PATCH 0/2] " Nithin Dabilpuram
2020-10-12  8:11 ` [dpdk-dev] [PATCH 1/2] test: add test case to validate VFIO DMA map/unmap Nithin Dabilpuram
2020-10-14 14:39   ` Burakov, Anatoly
2020-10-15  9:54     ` [dpdk-dev] [EXT] " Nithin Dabilpuram
2020-10-12  8:11 ` [dpdk-dev] [PATCH 2/2] vfio: fix partial DMA unmapping for VFIO type1 Nithin Dabilpuram
2020-10-14 15:07   ` Burakov, Anatoly
2020-10-15  6:09     ` [dpdk-dev] [EXT] " Nithin Dabilpuram
2020-10-15 10:00       ` Burakov, Anatoly
2020-10-15 11:38         ` Nithin Dabilpuram
2020-10-15 11:50         ` Nithin Dabilpuram
2020-10-15 11:57         ` Nithin Dabilpuram
2020-10-15 15:10           ` Burakov, Anatoly
2020-10-16  7:10             ` Nithin Dabilpuram
2020-10-17 16:14               ` Burakov, Anatoly
2020-10-19  9:43                 ` Nithin Dabilpuram
2020-10-22 12:13                   ` Nithin Dabilpuram
2020-10-28 13:04                     ` Burakov, Anatoly
2020-10-28 14:17                       ` Nithin Dabilpuram
2020-10-28 16:07                         ` Burakov, Anatoly
2020-10-28 16:31                           ` Nithin Dabilpuram
2020-11-05  9:04 ` [dpdk-dev] [PATCH v2 0/3] fix issue with partial DMA unmap Nithin Dabilpuram
2020-11-05  9:04   ` [dpdk-dev] [PATCH v2 1/3] vfio: revert changes for map contiguous areas in one go Nithin Dabilpuram
2020-11-05  9:04   ` [dpdk-dev] [PATCH v2 2/3] vfio: fix DMA mapping granularity for type1 iova as va Nithin Dabilpuram
2020-11-10 14:04     ` Burakov, Anatoly
2020-11-10 14:22       ` Burakov, Anatoly
2020-11-10 14:17     ` Burakov, Anatoly
2020-11-11  5:08       ` Nithin Dabilpuram
2020-11-11 10:00         ` Burakov, Anatoly
2020-11-05  9:04   ` [dpdk-dev] [PATCH v2 3/3] test: add test case to validate VFIO DMA map/unmap Nithin Dabilpuram
2020-12-01 19:32 ` [dpdk-dev] [PATCH v3 0/4] fix issue with partial DMA unmap Nithin Dabilpuram
2020-12-01 19:32   ` [dpdk-dev] [PATCH v3 1/4] vfio: revert changes for map contiguous areas in one go Nithin Dabilpuram
2020-12-01 19:33   ` [dpdk-dev] [PATCH v3 2/4] vfio: fix DMA mapping granularity for type1 IOVA as VA Nithin Dabilpuram
2020-12-01 19:33   ` [dpdk-dev] [PATCH v3 3/4] test: add test case to validate VFIO DMA map/unmap Nithin Dabilpuram
2020-12-01 19:33   ` [dpdk-dev] [PATCH v3 4/4] test: change external memory test to use system page sz Nithin Dabilpuram
2020-12-01 23:23     ` David Christensen
2020-12-02  5:40       ` Nithin Dabilpuram
2020-12-02  5:46 ` [dpdk-dev] [PATCH v4 0/4] fix issue with partial DMA unmap Nithin Dabilpuram
2020-12-02  5:46   ` [dpdk-dev] [PATCH v4 1/4] vfio: revert changes for map contiguous areas in one go Nithin Dabilpuram
2020-12-02 18:36     ` David Christensen
2020-12-02  5:46   ` [dpdk-dev] [PATCH v4 2/4] vfio: fix DMA mapping granularity for type1 IOVA as VA Nithin Dabilpuram
2020-12-02 18:38     ` David Christensen
2020-12-02  5:46   ` [dpdk-dev] [PATCH v4 3/4] test: add test case to validate VFIO DMA map/unmap Nithin Dabilpuram
2020-12-02 19:23     ` David Christensen
2020-12-03  7:14       ` Nithin Dabilpuram
2020-12-14  8:24         ` Nithin Dabilpuram
2020-12-02  5:46   ` [dpdk-dev] [PATCH v4 4/4] test: change external memory test to use system page sz Nithin Dabilpuram
2020-12-14  8:19 ` [dpdk-dev] [PATCH v5 0/4] fix issue with partial DMA unmap Nithin Dabilpuram
2020-12-14  8:19   ` [dpdk-dev] [PATCH v5 1/4] vfio: revert changes for map contiguous areas in one go Nithin Dabilpuram
2020-12-14  8:19   ` [dpdk-dev] [PATCH v5 2/4] vfio: fix DMA mapping granularity for type1 IOVA as VA Nithin Dabilpuram
2020-12-14  8:19   ` [dpdk-dev] [PATCH v5 3/4] test: add test case to validate VFIO DMA map/unmap Nithin Dabilpuram
2020-12-14  8:19   ` [dpdk-dev] [PATCH v5 4/4] test: change external memory test to use system page sz Nithin Dabilpuram
2020-12-17 19:06 ` [dpdk-dev] [PATCH v6 0/4] fix issue with partial DMA unmap Nithin Dabilpuram
2020-12-17 19:06   ` [dpdk-dev] [PATCH v6 1/4] vfio: revert changes for map contiguous areas in one go Nithin Dabilpuram
2020-12-17 19:06   ` [dpdk-dev] [PATCH v6 2/4] vfio: fix DMA mapping granularity for type1 IOVA as VA Nithin Dabilpuram
2020-12-17 19:06   ` [dpdk-dev] [PATCH v6 3/4] test: add test case to validate VFIO DMA map/unmap Nithin Dabilpuram
2020-12-17 19:10     ` Nithin Dabilpuram
2021-01-05 19:33       ` David Christensen
2021-01-06  8:40         ` Nithin Dabilpuram
2021-01-06 21:20           ` David Christensen
2020-12-17 19:06   ` [dpdk-dev] [PATCH v6 4/4] test: change external memory test to use system page sz Nithin Dabilpuram
2020-12-23  5:13   ` [dpdk-dev] [PATCH v6 0/4] fix issue with partial DMA unmap Nithin Dabilpuram
2021-01-04 22:29     ` David Christensen
2021-01-12 17:39 ` [dpdk-dev] [PATCH v7 0/3] " Nithin Dabilpuram
2021-01-12 17:39   ` [dpdk-dev] [PATCH v7 1/3] vfio: revert changes for map contiguous areas in one go Nithin Dabilpuram
2021-01-12 17:39   ` [dpdk-dev] [PATCH v7 2/3] vfio: fix DMA mapping granularity for type1 IOVA as VA Nithin Dabilpuram
2021-01-12 17:39   ` [dpdk-dev] [PATCH v7 3/3] test: change external memory test to use system page sz Nithin Dabilpuram
2021-01-14 16:30     ` David Marchand
2021-01-15  6:57       ` Nithin Dabilpuram
2021-01-15  7:32 ` [dpdk-dev] [PATCH v8 0/3] fix issue with partial DMA unmap Nithin Dabilpuram
2021-01-15  7:32   ` [dpdk-dev] [PATCH v8 1/3] vfio: revert changes for map contiguous areas in one go Nithin Dabilpuram
2021-03-05  7:50     ` David Marchand
2021-03-05 13:54       ` Burakov, Anatoly
2021-03-05 15:50         ` Nithin Dabilpuram
2021-04-01 11:27           ` Burakov, Anatoly
2021-01-15  7:32   ` [dpdk-dev] [PATCH v8 2/3] vfio: fix DMA mapping granularity for type1 IOVA as VA Nithin Dabilpuram
2021-01-15  7:32   ` [dpdk-dev] [PATCH v8 3/3] test: change external memory test to use system page sz Nithin Dabilpuram
2021-02-11 11:21     ` Burakov, Anatoly
2021-02-16 13:14   ` [dpdk-dev] [PATCH v8 0/3] fix issue with partial DMA unmap Burakov, Anatoly
2021-02-22  9:41     ` Nithin Dabilpuram
2021-02-22 10:06       ` David Marchand
2021-03-01 12:13   ` David Marchand [this message]

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