[V6,5/5] net: netvsc: Add Isolation VM support for netvsc driver

Commit Message

Tianyu Lan Dec. 7, 2021, 7:56 a.m. UTC

From: Tianyu Lan <[e-mail]>

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 address 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 <[e-mail]>
---
Change since v3:
       * Replace HV_HYP_PAGE_SIZE with PAGE_SIZE and virt_to_hvpfn()
         with vmalloc_to_pfn() in the hv_map_memory()

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(-)

Comments

Haiyang Zhang Dec. 8, 2021, 8:14 p.m. UTC | #1

> -----Original Message-----
> From: Tianyu Lan <[e-mail]>
> Sent: Tuesday, December 7, 2021 2:56 AM
> To: KY Srinivasan <[e-mail]>; Haiyang Zhang <[e-mail]>; Stephen
> Hemminger <[e-mail]>; [e-mail]; Dexuan Cui <[e-mail]>;
> [e-mail]; [e-mail]; [e-mail]; [e-mail];
> [e-mail]; [e-mail]; [e-mail]; [e-mail]; [e-mail];
> [e-mail]; [e-mail]; [e-mail]; [e-mail];
> [e-mail]; Tianyu Lan <[e-mail]>; [e-mail];
> Michael Kelley (LINUX) <[e-mail]>
> Cc: [e-mail]; [e-mail]; linux-
> [e-mail]; [e-mail]; [e-mail];
> [e-mail]; vkuznets <[e-mail]>; [e-mail];
> [e-mail]; [e-mail]; [e-mail]; [e-mail];
> [e-mail]
> Subject: [PATCH V6 5/5] net: netvsc: Add Isolation VM support for netvsc driver
> 
> From: Tianyu Lan <[e-mail]>
> 
> 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 address 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 <[e-mail]>
> ---
> Change since v3:
>        * Replace HV_HYP_PAGE_SIZE with PAGE_SIZE and virt_to_hvpfn()
>          with vmalloc_to_pfn() in the hv_map_memory()
> 
> 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..2b994117581e 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 / PAGE_SIZE,
> +				      sizeof(unsigned long), GFP_KERNEL);
> +	void *vaddr;
> +	int i;
> +
> +	if (!pfns)
> +		return NULL;
> +
> +	for (i = 0; i < size / PAGE_SIZE; i++)
> +		pfns[i] = vmalloc_to_pfn(addr + i * PAGE_SIZE) +
> +			(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;
> +		}

Returning EAGAIN will let the upper network layer busy retry, 
which may make things worse.
I suggest to return ENOSPC here like another place in this 
function, which will just drop the packet, and let the network 
protocol/app layer decide how to recover.

Thanks,
- Haiyang

Tianyu Lan Dec. 9, 2021, 8:08 a.m. UTC | #2

On 12/9/2021 4:14 AM, Haiyang Zhang wrote:
>> From: Tianyu Lan <[e-mail]>
>> Sent: Tuesday, December 7, 2021 2:56 AM
>> To: KY Srinivasan <[e-mail]>; Haiyang Zhang <[e-mail]>; Stephen
>> Hemminger <[e-mail]>; [e-mail]; Dexuan Cui <[e-mail]>;
>> [e-mail]; [e-mail]; [e-mail]; [e-mail];
>> [e-mail]; [e-mail]; [e-mail]; [e-mail]; [e-mail];
>> [e-mail]; [e-mail]; [e-mail]; [e-mail];
>> [e-mail]; Tianyu Lan <[e-mail]>; [e-mail];
>> Michael Kelley (LINUX) <[e-mail]>
>> Cc: [e-mail]; [e-mail]; linux-
>> [e-mail]; [e-mail]; [e-mail];
>> [e-mail]; vkuznets <[e-mail]>; [e-mail];
>> [e-mail]; [e-mail]; [e-mail]; [e-mail];
>> [e-mail]
>> Subject: [PATCH V6 5/5] net: netvsc: Add Isolation VM support for netvsc driver
>>
>> From: Tianyu Lan <[e-mail]>
>>
>> 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 address 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 <[e-mail]>
>> ---
>> Change since v3:
>>         * Replace HV_HYP_PAGE_SIZE with PAGE_SIZE and virt_to_hvpfn()
>>           with vmalloc_to_pfn() in the hv_map_memory()
>>
>> 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..2b994117581e 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 / PAGE_SIZE,
>> +				      sizeof(unsigned long), GFP_KERNEL);
>> +	void *vaddr;
>> +	int i;
>> +
>> +	if (!pfns)
>> +		return NULL;
>> +
>> +	for (i = 0; i < size / PAGE_SIZE; i++)
>> +		pfns[i] = vmalloc_to_pfn(addr + i * PAGE_SIZE) +
>> +			(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;
>> +		}
> 
> Returning EAGAIN will let the upper network layer busy retry,
> which may make things worse.
> I suggest to return ENOSPC here like another place in this
> function, which will just drop the packet, and let the network
> protocol/app layer decide how to recover.
> 

Yes, agree. Will update in the next version. Thanks.

Michael Kelley (LINUX) Dec. 9, 2021, 7:54 p.m. UTC | #3

From: Haiyang Zhang <[e-mail]> Sent: Wednesday, December 8, 2021 12:14 PM
> > From: Tianyu Lan <[e-mail]>
> > Sent: Tuesday, December 7, 2021 2:56 AM

[snip]

> >  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;
> > +		}
> 
> Returning EAGAIN will let the upper network layer busy retry,
> which may make things worse.
> I suggest to return ENOSPC here like another place in this
> function, which will just drop the packet, and let the network
> protocol/app layer decide how to recover.
> 
> Thanks,
> - Haiyang

I made the original suggestion to return -EAGAIN here.   A
DMA mapping failure should occur only if swiotlb bounce
buffer space is unavailable, which is a transient condition.
The existing code already stops the queue and returns
-EAGAIN when the ring buffer is full, which is also a transient
condition.  My sense is that the two conditions should be
handled the same way.  Or is there a reason why a ring
buffer full condition should stop the queue and retry, while
a mapping failure should drop the packet?

Michael

Haiyang Zhang Dec. 9, 2021, 8:40 p.m. UTC | #4

> -----Original Message-----
> From: Michael Kelley (LINUX) <[e-mail]>
> Sent: Thursday, December 9, 2021 2:54 PM
> To: Haiyang Zhang <[e-mail]>; Tianyu Lan <[e-mail]>; KY
> Srinivasan <[e-mail]>; Stephen Hemminger <[e-mail]>;
> [e-mail]; Dexuan Cui <[e-mail]>; [e-mail]; [e-mail];
> [e-mail]; [e-mail]; [e-mail]; [e-mail];
> [e-mail]; [e-mail]; [e-mail]; [e-mail];
> [e-mail]; [e-mail]; [e-mail]; [e-mail]; Tianyu
> Lan <[e-mail]>; [e-mail]
> Cc: [e-mail]; [e-mail]; linux-
> [e-mail]; [e-mail]; [e-mail];
> [e-mail]; vkuznets <[e-mail]>; [e-mail];
> [e-mail]; [e-mail]; [e-mail]; [e-mail];
> [e-mail]
> Subject: RE: [PATCH V6 5/5] net: netvsc: Add Isolation VM support for netvsc driver
> 
> From: Haiyang Zhang <[e-mail]> Sent: Wednesday, December 8, 2021 12:14 PM
> > > From: Tianyu Lan <[e-mail]>
> > > Sent: Tuesday, December 7, 2021 2:56 AM
> 
> [snip]
> 
> > >  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;
> > > +		}
> >
> > Returning EAGAIN will let the upper network layer busy retry,
> > which may make things worse.
> > I suggest to return ENOSPC here like another place in this
> > function, which will just drop the packet, and let the network
> > protocol/app layer decide how to recover.
> >
> > Thanks,
> > - Haiyang
> 
> I made the original suggestion to return -EAGAIN here.   A
> DMA mapping failure should occur only if swiotlb bounce
> buffer space is unavailable, which is a transient condition.
> The existing code already stops the queue and returns
> -EAGAIN when the ring buffer is full, which is also a transient
> condition.  My sense is that the two conditions should be
> handled the same way.  Or is there a reason why a ring
> buffer full condition should stop the queue and retry, while
> a mapping failure should drop the packet?

The netvsc_dma_map() fails in these two places. The dma_map_single() 
is doing the maping with swiotlb bounce buffer, correct? And it will 
become successful after the previous packets are unmapped?

+	packet->dma_range = kcalloc(page_count,
+				    sizeof(*packet->dma_range),
+				    GFP_KERNEL);

+		dma = dma_map_single(&hv_dev->device, src, len,
+				     DMA_TO_DEVICE);

I recalled your previous suggestion now, and agree with you that 
we can treat it the same way (return -EAGAIN) in this case. And 
the existing code will stop the queue temporarily.

Thanks,
- Haiyang

Patch

diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
index 69c7a57f3307..2b994117581e 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 / PAGE_SIZE,
+				      sizeof(unsigned long), GFP_KERNEL);
+	void *vaddr;
+	int i;
+
+	if (!pfns)
+		return NULL;
+
+	for (i = 0; i < size / PAGE_SIZE; i++)
+		pfns[i] = vmalloc_to_pfn(addr + i * PAGE_SIZE) +
+			(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,