From: "Burakov, Anatoly" <anatoly.burakov@intel.com> To: Nithin Dabilpuram <ndabilpuram@marvell.com> Cc: jerinj@marvell.com, dev@dpdk.org, stable@dpdk.org Subject: Re: [dpdk-stable] [PATCH 2/2] vfio: fix partial DMA unmapping for VFIO type1 Date: Wed, 14 Oct 2020 16:07:10 +0100 Message-ID: <05afb7f5-96bf-dffd-15dd-2024586f7290@intel.com> (raw) In-Reply-To: <20201012081106.10610-3-ndabilpuram@marvell.com> On 12-Oct-20 9:11 AM, Nithin Dabilpuram wrote: > Partial unmapping is not supported for VFIO IOMMU type1 > by kernel. Though kernel gives return as zero, the unmapped size > returned will not be same as expected. So check for > returned unmap size and return error. > > For case of DMA map/unmap triggered by heap allocations, > maintain granularity of memseg page size so that heap > expansion and contraction does not have this issue. This is quite unfortunate, because there was a different bug that had to do with kernel having a very limited number of mappings available [1], as a result of which the page concatenation code was added. It should therefore be documented that the dma_entry_limit parameter should be adjusted should the user run out of the DMA entries. [1] https://lore.kernel.org/lkml/155414977872.12780.13728555131525362206.stgit@gimli.home/T/ > > For user requested DMA map/unmap disallow partial unmapping > for VFIO type1. > > Fixes: 73a639085938 ("vfio: allow to map other memory regions") > Cc: anatoly.burakov@intel.com > Cc: stable@dpdk.org > > Signed-off-by: Nithin Dabilpuram <ndabilpuram@marvell.com> > --- > lib/librte_eal/linux/eal_vfio.c | 34 ++++++++++++++++++++++++++++------ > lib/librte_eal/linux/eal_vfio.h | 1 + > 2 files changed, 29 insertions(+), 6 deletions(-) > > diff --git a/lib/librte_eal/linux/eal_vfio.c b/lib/librte_eal/linux/eal_vfio.c > index d26e164..ef95259 100644 > --- a/lib/librte_eal/linux/eal_vfio.c > +++ b/lib/librte_eal/linux/eal_vfio.c > @@ -69,6 +69,7 @@ static const struct vfio_iommu_type iommu_types[] = { > { > .type_id = RTE_VFIO_TYPE1, > .name = "Type 1", > + .partial_unmap = false, > .dma_map_func = &vfio_type1_dma_map, > .dma_user_map_func = &vfio_type1_dma_mem_map > }, > @@ -76,6 +77,7 @@ static const struct vfio_iommu_type iommu_types[] = { > { > .type_id = RTE_VFIO_SPAPR, > .name = "sPAPR", > + .partial_unmap = true, > .dma_map_func = &vfio_spapr_dma_map, > .dma_user_map_func = &vfio_spapr_dma_mem_map > }, > @@ -83,6 +85,7 @@ static const struct vfio_iommu_type iommu_types[] = { > { > .type_id = RTE_VFIO_NOIOMMU, > .name = "No-IOMMU", > + .partial_unmap = true, > .dma_map_func = &vfio_noiommu_dma_map, > .dma_user_map_func = &vfio_noiommu_dma_mem_map > }, > @@ -525,12 +528,19 @@ vfio_mem_event_callback(enum rte_mem_event type, const void *addr, size_t len, > /* for IOVA as VA mode, no need to care for IOVA addresses */ > if (rte_eal_iova_mode() == RTE_IOVA_VA && msl->external == 0) { > uint64_t vfio_va = (uint64_t)(uintptr_t)addr; > - if (type == RTE_MEM_EVENT_ALLOC) > - vfio_dma_mem_map(default_vfio_cfg, vfio_va, vfio_va, > - len, 1); > - else > - vfio_dma_mem_map(default_vfio_cfg, vfio_va, vfio_va, > - len, 0); > + uint64_t page_sz = msl->page_sz; > + > + /* Maintain granularity of DMA map/unmap to memseg size */ > + for (; cur_len < len; cur_len += page_sz) { > + if (type == RTE_MEM_EVENT_ALLOC) > + vfio_dma_mem_map(default_vfio_cfg, vfio_va, > + vfio_va, page_sz, 1); > + else > + vfio_dma_mem_map(default_vfio_cfg, vfio_va, > + vfio_va, page_sz, 0); > + vfio_va += page_sz; > + } > + You'd also have to revert d1c7c0cdf7bac5eb40d3a2a690453aefeee5887b because currently the PA path will opportunistically concantenate contiguous segments into single mapping too. > return; > } > > @@ -1383,6 +1393,12 @@ vfio_type1_dma_mem_map(int vfio_container_fd, uint64_t vaddr, uint64_t iova, > RTE_LOG(ERR, EAL, " cannot clear DMA remapping, error %i (%s)\n", > errno, strerror(errno)); > return -1; > + } else if (dma_unmap.size != len) { > + RTE_LOG(ERR, EAL, " unexpected size %"PRIu64" of DMA " > + "remapping cleared instead of %"PRIu64"\n", > + (uint64_t)dma_unmap.size, len); > + rte_errno = EIO; > + return -1; > } > } > > @@ -1853,6 +1869,12 @@ container_dma_unmap(struct vfio_config *vfio_cfg, uint64_t vaddr, uint64_t iova, > /* we're partially unmapping a previously mapped region, so we > * need to split entry into two. > */ > + if (!vfio_cfg->vfio_iommu_type->partial_unmap) { > + RTE_LOG(DEBUG, EAL, "DMA partial unmap unsupported\n"); > + rte_errno = ENOTSUP; > + ret = -1; > + goto out; > + } How would we ever arrive here if we never do more than 1 page worth of memory anyway? I don't think this is needed. > if (user_mem_maps->n_maps == VFIO_MAX_USER_MEM_MAPS) { > RTE_LOG(ERR, EAL, "Not enough space to store partial mapping\n"); > rte_errno = ENOMEM; > diff --git a/lib/librte_eal/linux/eal_vfio.h b/lib/librte_eal/linux/eal_vfio.h > index cb2d35f..6ebaca6 100644 > --- a/lib/librte_eal/linux/eal_vfio.h > +++ b/lib/librte_eal/linux/eal_vfio.h > @@ -113,6 +113,7 @@ typedef int (*vfio_dma_user_func_t)(int fd, uint64_t vaddr, uint64_t iova, > struct vfio_iommu_type { > int type_id; > const char *name; > + bool partial_unmap; > vfio_dma_user_func_t dma_user_map_func; > vfio_dma_func_t dma_map_func; > }; > -- Thanks, Anatoly
next prev parent reply other threads:[~2020-10-14 15:07 UTC|newest] Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <20201012081106.10610-1-ndabilpuram@marvell.com> 2020-10-12 8:11 ` Nithin Dabilpuram 2020-10-14 15:07 ` Burakov, Anatoly [this message] 2020-10-15 6:09 ` [dpdk-stable] [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 ` [dpdk-stable] [dpdk-dev] " 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 [not found] ` <20201105090423.11954-1-ndabilpuram@marvell.com> 2020-11-05 9:04 ` [dpdk-stable] [PATCH v2 1/3] vfio: revert changes for map contiguous areas in one go Nithin Dabilpuram 2020-11-05 9:04 ` [dpdk-stable] [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 ` [dpdk-stable] [dpdk-dev] " Burakov, Anatoly 2020-11-10 14:17 ` [dpdk-stable] " Burakov, Anatoly 2020-11-11 5:08 ` [dpdk-stable] [dpdk-dev] " Nithin Dabilpuram 2020-11-11 10:00 ` Burakov, Anatoly [not found] ` <20201201193302.28131-1-ndabilpuram@marvell.com> 2020-12-01 19:32 ` [dpdk-stable] [PATCH v3 1/4] vfio: revert changes for map contiguous areas in one go Nithin Dabilpuram 2020-12-01 19:33 ` [dpdk-stable] [PATCH v3 2/4] vfio: fix DMA mapping granularity for type1 IOVA as VA Nithin Dabilpuram [not found] ` <20201202054647.3449-1-ndabilpuram@marvell.com> 2020-12-02 5:46 ` [dpdk-stable] [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-stable] [PATCH v4 2/4] vfio: fix DMA mapping granularity for type1 IOVA as VA Nithin Dabilpuram 2020-12-02 18:38 ` David Christensen [not found] ` <20201214081935.23577-1-ndabilpuram@marvell.com> 2020-12-14 8:19 ` [dpdk-stable] [PATCH v5 1/4] vfio: revert changes for map contiguous areas in one go Nithin Dabilpuram 2020-12-14 8:19 ` [dpdk-stable] [PATCH v5 2/4] vfio: fix DMA mapping granularity for type1 IOVA as VA Nithin Dabilpuram [not found] ` <20201217190604.29803-1-ndabilpuram@marvell.com> 2020-12-17 19:06 ` [dpdk-stable] [PATCH v6 1/4] vfio: revert changes for map contiguous areas in one go Nithin Dabilpuram 2020-12-17 19:06 ` [dpdk-stable] [PATCH v6 2/4] vfio: fix DMA mapping granularity for type1 IOVA as VA Nithin Dabilpuram [not found] ` <20210112173923.30320-1-ndabilpuram@marvell.com> 2021-01-12 17:39 ` [dpdk-stable] [PATCH v7 1/3] vfio: revert changes for map contiguous areas in one go Nithin Dabilpuram 2021-01-12 17:39 ` [dpdk-stable] [PATCH v7 2/3] vfio: fix DMA mapping granularity for type1 IOVA as VA Nithin Dabilpuram [not found] ` <20210115073243.7025-1-ndabilpuram@marvell.com> 2021-01-15 7:32 ` [dpdk-stable] [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 ` [dpdk-stable] [dpdk-dev] " Nithin Dabilpuram 2021-01-15 7:32 ` [dpdk-stable] [PATCH v8 2/3] vfio: fix DMA mapping granularity for type1 IOVA as VA Nithin Dabilpuram 2021-01-15 7:32 ` [dpdk-stable] [PATCH v8 3/3] test: change external memory test to use system page sz Nithin Dabilpuram 2021-02-11 11:21 ` Burakov, Anatoly
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