lkml.org 
[lkml]   [2022]   [May]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH] swiotlb: Max mapping size takes min align mask into account
    Date
    From: Tianyu Lan <Tianyu.Lan@microsoft.com>

    swiotlb_find_slots() skips slots according to io tlb aligned mask
    calculated from min aligned mask and original physical address
    offset. This affects max mapping size. The mapping size can't
    achieve the IO_TLB_SEGSIZE * IO_TLB_SIZE when original offset is
    non-zero. This will cause system boot up failure in Hyper-V
    Isolation VM where swiotlb force is enabled. Scsi layer use return
    value of dma_max_mapping_size() to set max segment size and it
    finally calls swiotlb_max_mapping_size(). Hyper-V storage driver
    sets min align mask to 4k - 1. Scsi layer may pass 256k length of
    request buffer with 0~4k offset and Hyper-V storage driver can't
    get swiotlb bounce buffer via DMA API. Swiotlb_find_slots() can't
    find 256k length bounce buffer with offset. Make swiotlb_max_mapping
    _size() take min align mask into account.

    Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
    ---
    kernel/dma/swiotlb.c | 13 ++++++++++++-
    1 file changed, 12 insertions(+), 1 deletion(-)

    diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
    index 73a41cec9e38..0d6684ca7eab 100644
    --- a/kernel/dma/swiotlb.c
    +++ b/kernel/dma/swiotlb.c
    @@ -743,7 +743,18 @@ dma_addr_t swiotlb_map(struct device *dev, phys_addr_t paddr, size_t size,

    size_t swiotlb_max_mapping_size(struct device *dev)
    {
    - return ((size_t)IO_TLB_SIZE) * IO_TLB_SEGSIZE;
    + int min_align_mask = dma_get_min_align_mask(dev);
    + int min_align = 0;
    +
    + /*
    + * swiotlb_find_slots() skips slots according to
    + * min align mask. This affects max mapping size.
    + * Take it into acount here.
    + */
    + if (min_align_mask)
    + min_align = roundup(min_align_mask, IO_TLB_SIZE);
    +
    + return ((size_t)IO_TLB_SIZE) * IO_TLB_SEGSIZE - min_align;
    }

    bool is_swiotlb_active(struct device *dev)
    --
    2.25.1
    \
     
     \ /
      Last update: 2022-05-10 16:57    [W:2.414 / U:0.060 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site