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>
---
drivers/net/hyperv/netvsc.c | 9 ++-------
1 file changed, 2 insertions(+), 7 deletions(-)
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 661bbe6..8acfa40 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -949,9 +949,6 @@ static void netvsc_copy_to_send_buf(struct netvsc_device *net_device,
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())
@@ -960,7 +957,7 @@ void netvsc_dma_unmap(struct hv_device *hv_dev,
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);
@@ -990,9 +987,7 @@ static int netvsc_dma_map(struct hv_device *hv_dev,
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;
--
1.8.3.1
