From: Michael Kelley mikelley@microsoft.com
commit 99f1c46011cc0feb47d4f4f7bee70a0341442d14 upstream.
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@vger.kernel.org Signed-off-by: Michael Kelley mikelley@microsoft.com Reviewed-by: Haiyang Zhang haiyangz@microsoft.com Link: https://lore.kernel.org/r/1675135986-254490-1-git-send-email-mikelley@micros... Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/hyperv/netvsc.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-)
--- a/drivers/net/hyperv/netvsc.c +++ b/drivers/net/hyperv/netvsc.c @@ -987,9 +987,6 @@ static void netvsc_copy_to_send_buf(stru void netvsc_dma_unmap(struct hv_device *hv_dev, struct hv_netvsc_packet *packet) { - u32 page_count = packet->cp_partial ? - packet->page_buf_cnt - packet->rmsg_pgcnt : - packet->page_buf_cnt; int i;
if (!hv_is_isolation_supported()) @@ -998,7 +995,7 @@ void netvsc_dma_unmap(struct hv_device * if (!packet->dma_range) return;
- for (i = 0; i < page_count; i++) + for (i = 0; i < packet->page_buf_cnt; i++) dma_unmap_single(&hv_dev->device, packet->dma_range[i].dma, packet->dma_range[i].mapping_size, DMA_TO_DEVICE); @@ -1028,9 +1025,7 @@ static int netvsc_dma_map(struct hv_devi struct hv_netvsc_packet *packet, struct hv_page_buffer *pb) { - u32 page_count = packet->cp_partial ? - packet->page_buf_cnt - packet->rmsg_pgcnt : - packet->page_buf_cnt; + u32 page_count = packet->page_buf_cnt; dma_addr_t dma; int i;