On Tue, Apr 13, 2021 at 11:22:16AM -0400, Tianyu Lan wrote:

From: Tianyu Lan <redacted>

In Isolation VM, all shared memory with host needs to mark visible
to host via hvcall. vmbus_establish_gpadl() has already done it for
netvsc rx/tx ring buffer. The page buffer used by vmbus_sendpacket_
pagebuffer() still need to handle. Use DMA API to map/umap these
memory during sending/receiving packet and Hyper-V DMA ops callback
will use swiotlb fucntion to allocate bounce buffer and copy data
from/to bounce buffer.

Signed-off-by: Tianyu Lan <redacted>
---
 drivers/net/hyperv/hyperv_net.h   |  11 +++
 drivers/net/hyperv/netvsc.c       | 137 ++++++++++++++++++++++++++++--
 drivers/net/hyperv/rndis_filter.c |   3 +
 3 files changed, 144 insertions(+), 7 deletions(-)

<...>

+	packet->dma_range = kzalloc(sizeof(struct dma_range) * page_count,
+			      GFP_KERNEL);
+	if (!packet->dma_range)
+		return -ENOMEM;
+
+	for (i = 0; i < page_count; i++) {
+		char *src = phys_to_virt((pb[i].pfn << HV_HYP_PAGE_SHIFT)
+					 + pb[i].offset);
+		u32 len = pb[i].len;
+
+		dma = dma_map_single(&hv_dev->device, src, len,
+				     DMA_TO_DEVICE);
+		if (dma_mapping_error(&hv_dev->device, dma))
+			return -ENOMEM;

Don't you leak dma_range here?

BTW, It will be easier if you CC all on all patches, so we will be able
to get whole context.

Thanks