[dpdk-dev] [PATCH v2 2/3] vfio: fix DMA mapping granularity for type1 iova as va
Nithin Dabilpuram
nithind1988 at gmail.com
Wed Nov 11 06:08:53 CET 2020
On Tue, Nov 10, 2020 at 02:17:39PM +0000, Burakov, Anatoly wrote:
> On 05-Nov-20 9:04 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 IOVA as PA, DMA mapping is already at memseg size
> > granularity. Do the same even for IOVA as VA mode as
> > DMA map/unmap triggered by heap allocations,
> > maintain granularity of memseg page size so that heap
> > expansion and contraction does not have this issue.
> >
> > For user requested DMA map/unmap disallow partial unmapping
> > for VFIO type1.
> >
> > Fixes: 73a639085938 ("vfio: allow to map other memory regions")
> > Cc: anatoly.burakov at intel.com
> > Cc: stable at dpdk.org
> >
> > Signed-off-by: Nithin Dabilpuram <ndabilpuram at marvell.com>
> > ---
>
> <snip>
>
> > @@ -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);
>
> I think you're mapping the same address here, over and over. Perhaps you
> meant `vfio_va + cur_len` for the mapping addresses?
There is a 'vfio_va += page_sz;' in next line right ?
>
> --
> Thanks,
> Anatoly
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