Re: [RFC PATCH V3 10/11] HV/Netvsc: Add Isolation VM support for netvsc driver

From: Vitaly Kuznetsov
Date: Thu Jun 10 2021 - 05:52:11 EST


Tianyu Lan <ltykernel@xxxxxxxxx> writes:

> From: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>
>
> 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 function to allocate bounce buffer and copy data
> from/to bounce buffer.
>
> Signed-off-by: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>
> ---
> drivers/net/hyperv/hyperv_net.h | 6 ++
> drivers/net/hyperv/netvsc.c | 125 ++++++++++++++++++++++++++++--
> drivers/net/hyperv/rndis_filter.c | 3 +
> include/linux/hyperv.h | 5 ++
> 4 files changed, 133 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
> index b11aa68b44ec..c2fbb9d4df2c 100644
> --- a/drivers/net/hyperv/hyperv_net.h
> +++ b/drivers/net/hyperv/hyperv_net.h
> @@ -164,6 +164,7 @@ struct hv_netvsc_packet {
> u32 total_bytes;
> u32 send_buf_index;
> u32 total_data_buflen;
> + struct hv_dma_range *dma_range;
> };
>
> #define NETVSC_HASH_KEYLEN 40
> @@ -1074,6 +1075,7 @@ struct netvsc_device {
>
> /* Receive buffer allocated by us but manages by NetVSP */
> void *recv_buf;
> + void *recv_original_buf;
> u32 recv_buf_size; /* allocated bytes */
> u32 recv_buf_gpadl_handle;
> u32 recv_section_cnt;
> @@ -1082,6 +1084,8 @@ struct netvsc_device {
>
> /* Send buffer allocated by us */
> void *send_buf;
> + void *send_original_buf;
> + u32 send_buf_size;
> u32 send_buf_gpadl_handle;
> u32 send_section_cnt;
> u32 send_section_size;
> @@ -1729,4 +1733,6 @@ struct rndis_message {
> #define RETRY_US_HI 10000
> #define RETRY_MAX 2000 /* >10 sec */
>
> +void netvsc_dma_unmap(struct hv_device *hv_dev,
> + struct hv_netvsc_packet *packet);
> #endif /* _HYPERV_NET_H */
> diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
> index 7bd935412853..a01740c6c6b8 100644
> --- a/drivers/net/hyperv/netvsc.c
> +++ b/drivers/net/hyperv/netvsc.c
> @@ -153,8 +153,21 @@ static void free_netvsc_device(struct rcu_head *head)
> int i;
>
> kfree(nvdev->extension);
> - vfree(nvdev->recv_buf);
> - vfree(nvdev->send_buf);
> +
> + if (nvdev->recv_original_buf) {
> + vunmap(nvdev->recv_buf);
> + vfree(nvdev->recv_original_buf);
> + } else {
> + vfree(nvdev->recv_buf);
> + }
> +
> + if (nvdev->send_original_buf) {
> + vunmap(nvdev->send_buf);
> + vfree(nvdev->send_original_buf);
> + } else {
> + vfree(nvdev->send_buf);
> + }
> +
> kfree(nvdev->send_section_map);
>
> for (i = 0; i < VRSS_CHANNEL_MAX; i++) {
> @@ -338,8 +351,10 @@ static int netvsc_init_buf(struct hv_device *device,
> struct net_device *ndev = hv_get_drvdata(device);
> struct nvsp_message *init_packet;
> unsigned int buf_size;
> + unsigned long *pfns;
> size_t map_words;
> int i, ret = 0;
> + void *vaddr;
>
> /* Get receive buffer area. */
> buf_size = device_info->recv_sections * device_info->recv_section_size;
> @@ -375,6 +390,21 @@ static int netvsc_init_buf(struct hv_device *device,
> goto cleanup;
> }
>
> + if (hv_isolation_type_snp()) {
> + pfns = kcalloc(buf_size / HV_HYP_PAGE_SIZE, sizeof(unsigned long),
> + GFP_KERNEL);
> + for (i = 0; i < buf_size / HV_HYP_PAGE_SIZE; i++)
> + pfns[i] = virt_to_hvpfn(net_device->recv_buf + i * HV_HYP_PAGE_SIZE) +
> + (ms_hyperv.shared_gpa_boundary >> HV_HYP_PAGE_SHIFT);
> +
> + vaddr = vmap_pfn(pfns, buf_size / HV_HYP_PAGE_SIZE, PAGE_KERNEL_IO);
> + kfree(pfns);
> + if (!vaddr)
> + goto cleanup;
> + net_device->recv_original_buf = net_device->recv_buf;
> + net_device->recv_buf = vaddr;
> + }
> +
> /* Notify the NetVsp of the gpadl handle */
> init_packet = &net_device->channel_init_pkt;
> memset(init_packet, 0, sizeof(struct nvsp_message));
> @@ -477,6 +507,23 @@ static int netvsc_init_buf(struct hv_device *device,
> goto cleanup;
> }
>
> + if (hv_isolation_type_snp()) {
> + pfns = kcalloc(buf_size / HV_HYP_PAGE_SIZE, sizeof(unsigned long),
> + GFP_KERNEL);
> +
> + for (i = 0; i < buf_size / HV_HYP_PAGE_SIZE; i++)
> + pfns[i] = virt_to_hvpfn(net_device->send_buf + i * HV_HYP_PAGE_SIZE)
> + + (ms_hyperv.shared_gpa_boundary >> HV_HYP_PAGE_SHIFT);
> +
> + vaddr = vmap_pfn(pfns, buf_size / HV_HYP_PAGE_SIZE, PAGE_KERNEL_IO);
> + kfree(pfns);
> + if (!vaddr)
> + goto cleanup;
> +
> + net_device->send_original_buf = net_device->send_buf;
> + net_device->send_buf = vaddr;
> + }
> +
> /* Notify the NetVsp of the gpadl handle */
> init_packet = &net_device->channel_init_pkt;
> memset(init_packet, 0, sizeof(struct nvsp_message));
> @@ -767,7 +814,7 @@ static void netvsc_send_tx_complete(struct net_device *ndev,
>
> /* Notify the layer above us */
> if (likely(skb)) {
> - const struct hv_netvsc_packet *packet
> + struct hv_netvsc_packet *packet
> = (struct hv_netvsc_packet *)skb->cb;
> u32 send_index = packet->send_buf_index;
> struct netvsc_stats *tx_stats;
> @@ -783,6 +830,7 @@ static void netvsc_send_tx_complete(struct net_device *ndev,
> tx_stats->bytes += packet->total_bytes;
> u64_stats_update_end(&tx_stats->syncp);
>
> + netvsc_dma_unmap(ndev_ctx->device_ctx, packet);
> napi_consume_skb(skb, budget);
> }
>
> @@ -947,6 +995,63 @@ static void netvsc_copy_to_send_buf(struct netvsc_device *net_device,
> memset(dest, 0, padding);
> }
>
> +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 (!packet->dma_range)
> + return;
> +
> + for (i = 0; i < page_count; i++)
> + dma_unmap_single(&hv_dev->device, packet->dma_range[i].dma,
> + packet->dma_range[i].mapping_size,
> + DMA_TO_DEVICE);
> +
> + kfree(packet->dma_range);
> +}
> +
> +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;
> + dma_addr_t dma;
> + int i;
> +
> + packet->dma_range = kcalloc(page_count,
> + sizeof(*packet->dma_range),
> + 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)) {
> + kfree(packet->dma_range);
> + return -ENOMEM;
> + }
> +
> + packet->dma_range[i].dma = dma;
> + packet->dma_range[i].mapping_size = len;
> + pb[i].pfn = dma >> HV_HYP_PAGE_SHIFT;
> + pb[i].offset = offset_in_hvpage(dma);
> + pb[i].len = len;
> + }
> +
> + return 0;
> +}
> +
> static inline int netvsc_send_pkt(
> struct hv_device *device,
> struct hv_netvsc_packet *packet,
> @@ -987,14 +1092,22 @@ static inline int netvsc_send_pkt(
>
> trace_nvsp_send_pkt(ndev, out_channel, rpkt);
>
> + packet->dma_range = NULL;
> if (packet->page_buf_cnt) {
> if (packet->cp_partial)
> pb += packet->rmsg_pgcnt;
>
> + ret = netvsc_dma_map(ndev_ctx->device_ctx, packet, pb);
> + if (ret)
> + return ret;
> +
> ret = vmbus_sendpacket_pagebuffer(out_channel,
> - pb, packet->page_buf_cnt,
> - &nvmsg, sizeof(nvmsg),
> - req_id);
> + pb, packet->page_buf_cnt,
> + &nvmsg, sizeof(nvmsg),
> + req_id);

Nitpick: stray change?

> +
> + if (ret)
> + netvsc_dma_unmap(ndev_ctx->device_ctx, packet);
> } else {
> ret = vmbus_sendpacket(out_channel,
> &nvmsg, sizeof(nvmsg),
> diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c
> index 983bf362466a..448c1ee39246 100644
> --- a/drivers/net/hyperv/rndis_filter.c
> +++ b/drivers/net/hyperv/rndis_filter.c
> @@ -293,6 +293,8 @@ static void rndis_filter_receive_response(struct net_device *ndev,
> u32 *req_id = &resp->msg.init_complete.req_id;
> struct rndis_device *dev = nvdev->extension;
> struct rndis_request *request = NULL;
> + struct hv_device *hv_dev = ((struct net_device_context *)
> + netdev_priv(ndev))->device_ctx;
> bool found = false;
> unsigned long flags;
>
> @@ -361,6 +363,7 @@ static void rndis_filter_receive_response(struct net_device *ndev,
> }
> }
>
> + netvsc_dma_unmap(hv_dev, &request->pkt);
> complete(&request->wait_event);
> } else {
> netdev_err(ndev,
> diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
> index babbe19f57e2..90abff664495 100644
> --- a/include/linux/hyperv.h
> +++ b/include/linux/hyperv.h
> @@ -1616,6 +1616,11 @@ struct hyperv_service_callback {
> void (*callback)(void *context);
> };
>
> +struct hv_dma_range {
> + dma_addr_t dma;
> + u32 mapping_size;
> +};
> +
> #define MAX_SRV_VER 0x7ffffff
> extern bool vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp, u8 *buf, u32 buflen,
> const int *fw_version, int fw_vercnt,

--
Vitaly