> -----Original Message-----
> From: Dexuan Cui <[email protected]>
> Sent: Wednesday, June 17, 2026 11:50 PM
> To: KY Srinivasan <[email protected]>; Haiyang Zhang
> <[email protected]>; [email protected]; Dexuan Cui
> <[email protected]>; Long Li <[email protected]>;
> [email protected]; [email protected]; [email protected];
> [email protected]; [email protected]; Konstantin Taranov
> <[email protected]>; [email protected]; [email protected];
> [email protected]; [email protected]; [email protected];
> [email protected]; [email protected];
> [email protected]; [email protected]; linux-
> [email protected]
> Cc: [email protected]
> Subject: [PATCH net] net: mana: Sync page pool RX frags for CPU
>
> MANA allocates RX buffers from page pool fragments when frag_count is
> greater than 1. In that case the buffers remain DMA mapped by page pool
> and the RX completion path does not call dma_unmap_single(). As a result,
> the implicit sync-for-CPU normally performed by dma_unmap_single() is
> missing before the packet data is passed to the networking stack.
>
> This breaks RX on configurations which require explicit DMA syncing, for
> example when booted with swiotlb=force.
>
> Fix this by recording the page pool page and DMA sync offset when the RX
> buffer is allocated, and syncing the received packet range for CPU access
> before handing the RX buffer to the stack.
>
> Also validate the packet length reported in the RX CQE before using it as
> a DMA sync length or passing it to skb processing. The CQE is supplied
> by the device and should not be blindly trusted by Confidential VMs.
>
> Fixes: 730ff06d3f5c ("net: mana: Use page pool fragments for RX buffers
> instead of full pages to improve memory efficiency.")
> Cc: [email protected]
> Signed-off-by: Dexuan Cui <[email protected]>
> ---
> drivers/net/ethernet/microsoft/mana/mana_en.c | 61 +++++++++++++++----
> include/net/mana/mana.h | 8 +++
> 2 files changed, 57 insertions(+), 12 deletions(-)
Reviewed-by: Haiyang Zhang <[email protected]>
