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

[Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>]

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