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: [email protected]
Signed-off-by: Michael Kelley <[email protected]>
Reviewed-by: Haiyang Zhang <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Paolo Abeni <[email protected]>

0 files changed, 0 insertions, 0 deletions