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RE: [PATCH V3 5/5] hv_netvsc: Add Isolation VM support for netvsc driver



From: Tianyu Lan <ltykernel@xxxxxxxxx> Sent: Wednesday, December 1, 2021 8:03 AM
> 
> 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() stills need to be handled. Use DMA API to map/umap
> these memory during sending/receiving packet and Hyper-V swiotlb
> bounce buffer dma adress will be returned. The swiotlb bounce buffer
> has been masked to be visible to host during boot up.
> 
> rx/tx ring buffer is allocated via vzalloc() and they need to be
> mapped into unencrypted address space(above vTOM) before sharing
> with host and accessing. Add hv_map/unmap_memory() to map/umap rx
> /tx ring buffer.
> 
> Signed-off-by: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>
> ---
> Change since v2:
>        * Add hv_map/unmap_memory() to map/umap rx/tx ring buffer.
> ---
>  arch/x86/hyperv/ivm.c             |  28 ++++++
>  drivers/hv/hv_common.c            |  11 +++
>  drivers/net/hyperv/hyperv_net.h   |   5 ++
>  drivers/net/hyperv/netvsc.c       | 136 +++++++++++++++++++++++++++++-
>  drivers/net/hyperv/netvsc_drv.c   |   1 +
>  drivers/net/hyperv/rndis_filter.c |   2 +
>  include/asm-generic/mshyperv.h    |   2 +
>  include/linux/hyperv.h            |   5 ++
>  8 files changed, 187 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
> index 69c7a57f3307..9f78d8f67ea3 100644
> --- a/arch/x86/hyperv/ivm.c
> +++ b/arch/x86/hyperv/ivm.c
> @@ -287,3 +287,31 @@ int hv_set_mem_host_visibility(unsigned long kbuffer, 
> int pagecount, bool visibl
>       kfree(pfn_array);
>       return ret;
>  }
> +
> +/*
> + * hv_map_memory - map memory to extra space in the AMD SEV-SNP Isolation VM.
> + */
> +void *hv_map_memory(void *addr, unsigned long size)
> +{
> +     unsigned long *pfns = kcalloc(size / HV_HYP_PAGE_SIZE,

This should be just PAGE_SIZE, as this code is unrelated to communication
with Hyper-V.

> +                                   sizeof(unsigned long), GFP_KERNEL);
> +     void *vaddr;
> +     int i;
> +
> +     if (!pfns)
> +             return NULL;
> +
> +     for (i = 0; i < size / PAGE_SIZE; i++)
> +             pfns[i] = virt_to_hvpfn(addr + i * PAGE_SIZE) +

Same here:  Use virt_to_pfn().

> +                     (ms_hyperv.shared_gpa_boundary >> PAGE_SHIFT);
> +
> +     vaddr = vmap_pfn(pfns, size / PAGE_SIZE, PAGE_KERNEL_IO);
> +     kfree(pfns);
> +
> +     return vaddr;
> +}
> +
> +void hv_unmap_memory(void *addr)
> +{
> +     vunmap(addr);
> +}
> diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
> index 7be173a99f27..3c5cb1f70319 100644
> --- a/drivers/hv/hv_common.c
> +++ b/drivers/hv/hv_common.c
> @@ -295,3 +295,14 @@ u64 __weak hv_ghcb_hypercall(u64 control, void *input, 
> void *output, u32 input_s
>       return HV_STATUS_INVALID_PARAMETER;
>  }
>  EXPORT_SYMBOL_GPL(hv_ghcb_hypercall);
> +
> +void __weak *hv_map_memory(void *addr, unsigned long size)
> +{
> +     return NULL;
> +}
> +EXPORT_SYMBOL_GPL(hv_map_memory);
> +
> +void __weak hv_unmap_memory(void *addr)
> +{
> +}
> +EXPORT_SYMBOL_GPL(hv_unmap_memory);
> diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
> index 315278a7cf88..cf69da0e296c 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 */
>       struct vmbus_gpadl recv_buf_gpadl_handle;
>       u32 recv_section_cnt;
> @@ -1082,6 +1084,7 @@ struct netvsc_device {
> 
>       /* Send buffer allocated by us */
>       void *send_buf;
> +     void *send_original_buf;
>       u32 send_buf_size;
>       struct vmbus_gpadl send_buf_gpadl_handle;
>       u32 send_section_cnt;
> @@ -1731,4 +1734,6 @@ 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 396bc1c204e6..b7ade735a806 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) {
> +             hv_unmap_memory(nvdev->recv_buf);
> +             vfree(nvdev->recv_original_buf);
> +     } else {
> +             vfree(nvdev->recv_buf);
> +     }
> +
> +     if (nvdev->send_original_buf) {
> +             hv_unmap_memory(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++) {
> @@ -338,6 +351,7 @@ static int netvsc_init_buf(struct hv_device *device,
>       unsigned int buf_size;
>       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;
> @@ -373,6 +387,17 @@ static int netvsc_init_buf(struct hv_device *device,
>               goto cleanup;
>       }
> 
> +     if (hv_isolation_type_snp()) {
> +             vaddr = hv_map_memory(net_device->recv_buf, buf_size);
> +             if (!vaddr) {
> +                     ret = -ENOMEM;
> +                     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));
> @@ -476,6 +501,17 @@ static int netvsc_init_buf(struct hv_device *device,
>               goto cleanup;
>       }
> 
> +     if (hv_isolation_type_snp()) {
> +             vaddr = hv_map_memory(net_device->send_buf, buf_size);
> +             if (!vaddr) {
> +                     ret = -ENOMEM;
> +                     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));
> @@ -766,7 +802,7 @@ 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;
> @@ -782,6 +818,7 @@ 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);
>       }
> 
> @@ -946,6 +983,88 @@ 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 (!hv_is_isolation_supported())
> +             return;
> +
> +     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);
> +}
> +
> +/* netvsc_dma_map - Map swiotlb bounce buffer with data page of
> + * packet sent by vmbus_sendpacket_pagebuffer() in the Isolation
> + * VM.
> + *
> + * In isolation VM, netvsc send buffer has been marked visible to
> + * host and so the data copied to send buffer doesn't need to use
> + * bounce buffer. The data pages handled by vmbus_sendpacket_pagebuffer()
> + * may not be copied to send buffer and so these pages need to be
> + * mapped with swiotlb bounce buffer. netvsc_dma_map() is to do
> + * that. The pfns in the struct hv_page_buffer need to be converted
> + * to bounce buffer's pfn. The loop here is necessary because the
> + * entries in the page buffer array are not necessarily full
> + * pages of data.  Each entry in the array has a separate offset and
> + * len that may be non-zero, even for entries in the middle of the
> + * array.  And the entries are not physically contiguous.  So each
> + * entry must be individually mapped rather than as a contiguous unit.
> + * So not use dma_map_sg() here.
> + */
> +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;
> +
> +     if (!hv_is_isolation_supported())
> +             return 0;
> +
> +     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;
> +             }
> +
> +             /* pb[].offset and pb[].len are not changed during dma mapping
> +              * and so not reassign.
> +              */
> +             packet->dma_range[i].dma = dma;
> +             packet->dma_range[i].mapping_size = len;
> +             pb[i].pfn = dma >> HV_HYP_PAGE_SHIFT;
> +     }
> +
> +     return 0;
> +}
> +
>  static inline int netvsc_send_pkt(
>       struct hv_device *device,
>       struct hv_netvsc_packet *packet,
> @@ -986,14 +1105,24 @@ 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) {
> +                     ret = -EAGAIN;
> +                     goto exit;
> +             }
> +
>               ret = vmbus_sendpacket_pagebuffer(out_channel,
>                                                 pb, packet->page_buf_cnt,
>                                                 &nvmsg, sizeof(nvmsg),
>                                                 req_id);
> +
> +             if (ret)
> +                     netvsc_dma_unmap(ndev_ctx->device_ctx, packet);
>       } else {
>               ret = vmbus_sendpacket(out_channel,
>                                      &nvmsg, sizeof(nvmsg),
> @@ -1001,6 +1130,7 @@ static inline int netvsc_send_pkt(
>                                      
> VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
>       }
> 
> +exit:
>       if (ret == 0) {
>               atomic_inc_return(&nvchan->queue_sends);
> 
> diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
> index 7e66ae1d2a59..17958533bf30 100644
> --- a/drivers/net/hyperv/netvsc_drv.c
> +++ b/drivers/net/hyperv/netvsc_drv.c
> @@ -2512,6 +2512,7 @@ static int netvsc_probe(struct hv_device *dev,
>       net->netdev_ops = &device_ops;
>       net->ethtool_ops = &ethtool_ops;
>       SET_NETDEV_DEV(net, &dev->device);
> +     dma_set_min_align_mask(&dev->device, HV_HYP_PAGE_SIZE - 1);
> 
>       /* We always need headroom for rndis header */
>       net->needed_headroom = RNDIS_AND_PPI_SIZE;
> diff --git a/drivers/net/hyperv/rndis_filter.c 
> b/drivers/net/hyperv/rndis_filter.c
> index f6c9c2a670f9..448fcc325ed7 100644
> --- a/drivers/net/hyperv/rndis_filter.c
> +++ b/drivers/net/hyperv/rndis_filter.c
> @@ -361,6 +361,8 @@ static void rndis_filter_receive_response(struct 
> net_device *ndev,
>                       }
>               }
> 
> +             netvsc_dma_unmap(((struct net_device_context *)
> +                     netdev_priv(ndev))->device_ctx, &request->pkt);
>               complete(&request->wait_event);
>       } else {
>               netdev_err(ndev,
> diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
> index 3e2248ac328e..94e73ba129c5 100644
> --- a/include/asm-generic/mshyperv.h
> +++ b/include/asm-generic/mshyperv.h
> @@ -269,6 +269,8 @@ bool hv_isolation_type_snp(void);
>  u64 hv_ghcb_hypercall(u64 control, void *input, void *output, u32 
> input_size);
>  void hyperv_cleanup(void);
>  bool hv_query_ext_cap(u64 cap_query);
> +void *hv_map_memory(void *addr, unsigned long size);
> +void hv_unmap_memory(void *addr);
>  #else /* CONFIG_HYPERV */
>  static inline bool hv_is_hyperv_initialized(void) { return false; }
>  static inline bool hv_is_hibernation_supported(void) { return false; }
> diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
> index 74f5e92f91a0..b53cfc4163af 100644
> --- a/include/linux/hyperv.h
> +++ b/include/linux/hyperv.h
> @@ -1584,6 +1584,11 @@ 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,
> --
> 2.25.1




 


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