1. Jul 28, 2021
  2. Jul 21, 2021
    • Markus Boehme's avatar
      ixgbe: Fix packet corruption due to missing DMA sync · 09cfae9f
      Markus Boehme authored
      When receiving a packet with multiple fragments, hardware may still
      touch the first fragment until the entire packet has been received. The
      driver therefore keeps the first fragment mapped for DMA until end of
      packet has been asserted, and delays its dma_sync call until then.
      
      The driver tries to fit multiple receive buffers on one page. When using
      3K receive buffers (e.g. using Jumbo frames and legacy-rx is turned
      off/build_skb is being used) on an architecture with 4K pages, the
      driver allocates an order 1 compound page and uses one page per receive
      buffer. To determine the correct offset for a delayed DMA sync of the
      first fragment of a multi-fragment packet, the driver then cannot just
      use PAGE_MASK on the DMA address but has to construct a mask based on
      the actual size of the backing page.
      
      Using PAGE_MASK in the 3K RX buffer/4K page architecture configuration
      will always sync the first page of a compound page. With the SWIOTLB
      enabled this can lead to corrupted packets (zeroed out first fragment,
      re-used garbage from another packet) and various consequences, such as
      slow/stalling data transfers and connection resets. For example, testing
      on a link with MTU exceeding 3058 bytes on a host with SWIOTLB enabled
      (e.g. "iommu=soft swiotlb=262144,force") TCP transfers quickly fizzle
      out without this patch.
      
      Cc: stable@vger.kernel.org
      Fixes: 0c5661ec
      
       ("ixgbe: fix crash in build_skb Rx code path")
      Signed-off-by: default avatarMarkus Boehme <markubo@amazon.com>
      Tested-by: default avatarTony Brelinski <tonyx.brelinski@intel.com>
      Signed-off-by: default avatarTony Nguyen <anthony.l.nguyen@intel.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      09cfae9f
  3. Jul 20, 2021
  4. Jul 19, 2021