Re: [RFC V2 PATCH 11/12] HV/Netvsc: Add Isolation VM support for netvsc driver

[Leon Romanovsky <leon@kernel.org>]

On Tue, Apr 13, 2021 at 11:22:16AM -0400, Tianyu Lan wrote:
> From: Tianyu Lan <Tianyu.Lan@microsoft.com>
> 
> 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 <Tianyu.Lan@microsoft.com>
> ---
>  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