> -----Original Message-----
> From: Michael Kelley (LINUX) <mikelley@xxxxxxxxxxxxx>
> Sent: Monday, January 30, 2023 10:33 PM
> To: KY Srinivasan <kys@xxxxxxxxxxxxx>; Haiyang Zhang
> <haiyangz@xxxxxxxxxxxxx>; wei.liu@xxxxxxxxxx; Dexuan Cui
> <decui@xxxxxxxxxxxxx>; davem@xxxxxxxxxxxxx; edumazet@xxxxxxxxxx;
> kuba@xxxxxxxxxx; pabeni@xxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; linux-
> hyperv@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Cc: Michael Kelley (LINUX) <mikelley@xxxxxxxxxxxxx>; stable@xxxxxxxxxxxxxxx
> Subject: [PATCH net 1/1] hv_netvsc: Fix missed pagebuf entries in
> netvsc_dma_map/unmap()
>
> netvsc_dma_map() and netvsc_dma_unmap() currently check the cp_partial
> flag and adjust the page_count so that pagebuf entries for the RNDIS
> portion of the message are skipped when it has already been copied into
> a send buffer. But this adjustment has already been made by code in
> netvsc_send(). The duplicate adjustment causes some pagebuf entries to
> not be mapped. In a normal VM, this doesn't break anything because the
> mapping doesn’t change the PFN. But in a Confidential VM,
> dma_map_single() does bounce buffering and provides a different PFN.
> Failing to do the mapping causes the wrong PFN to be passed to Hyper-V,
> and various errors ensue.
>
> Fix this by removing the duplicate adjustment in netvsc_dma_map() and
> netvsc_dma_unmap().
>
> Fixes: 846da38de0e8 ("net: netvsc: Add Isolation VM support for netvsc
> driver")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
Reviewed-by: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
Thanks!
