RE: [PATCH V2 5/6] net: netvsc: Add Isolation VM support for netvsc driver

From: Michael Kelley (LINUX)
Date: Tue Nov 23 2021 - 12:55:59 EST

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In reply to: Tianyu Lan: "[PATCH V2 5/6] net: netvsc: Add Isolation VM support for netvsc driver"
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From: Tianyu Lan <ltykernel@xxxxxxxxx> Sent: Tuesday, November 23, 2021 6:31 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 address will be returned. The swiotlb bounce buffer
> has been masked to be visible to host during boot up.
>
> Allocate rx/tx ring buffer via dma_alloc_noncontiguous() in Isolation
> VM. After calling vmbus_establish_gpadl() which marks these pages visible
> to host, map these pages unencrypted addes space via dma_vmap_noncontiguous().
>
> Signed-off-by: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>
> ---
> drivers/net/hyperv/hyperv_net.h | 5 +
> drivers/net/hyperv/netvsc.c | 192 +++++++++++++++++++++++++++---
> drivers/net/hyperv/rndis_filter.c | 2 +
> include/linux/hyperv.h | 6 +
> 4 files changed, 190 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
> index 315278a7cf88..31c77a00d01e 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;
> + struct sg_table *recv_sgt;
> 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;
> + struct sg_table *send_sgt;
> 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..9cdc71930830 100644
> --- a/drivers/net/hyperv/netvsc.c
> +++ b/drivers/net/hyperv/netvsc.c
> @@ -20,6 +20,7 @@
> #include <linux/vmalloc.h>
> #include <linux/rtnetlink.h>
> #include <linux/prefetch.h>
> +#include <linux/gfp.h>
>
> #include <asm/sync_bitops.h>
> #include <asm/mshyperv.h>
> @@ -146,15 +147,39 @@ static struct netvsc_device *alloc_net_device(void)
> return net_device;
> }
>
> +static struct hv_device *netvsc_channel_to_device(struct vmbus_channel *channel)
> +{
> + struct vmbus_channel *primary = channel->primary_channel;
> +
> + return primary ? primary->device_obj : channel->device_obj;
> +}
> +
> static void free_netvsc_device(struct rcu_head *head)
> {
> struct netvsc_device *nvdev
> = container_of(head, struct netvsc_device, rcu);
> + struct hv_device *dev =
> + netvsc_channel_to_device(nvdev->chan_table[0].channel);
> int i;
>
> kfree(nvdev->extension);
> - vfree(nvdev->recv_buf);
> - vfree(nvdev->send_buf);
> +
> + if (nvdev->recv_sgt) {
> + dma_vunmap_noncontiguous(&dev->device, nvdev->recv_buf);
> + dma_free_noncontiguous(&dev->device, nvdev->recv_buf_size,
> + nvdev->recv_sgt, DMA_FROM_DEVICE);
> + } else {
> + vfree(nvdev->recv_buf);
> + }
> +
> + if (nvdev->send_sgt) {
> + dma_vunmap_noncontiguous(&dev->device, nvdev->send_buf);
> + dma_free_noncontiguous(&dev->device, nvdev->send_buf_size,
> + nvdev->send_sgt, DMA_TO_DEVICE);
> + } else {
> + vfree(nvdev->send_buf);
> + }
> +
> kfree(nvdev->send_section_map);
>
> for (i = 0; i < VRSS_CHANNEL_MAX; i++) {
> @@ -348,7 +373,21 @@ static int netvsc_init_buf(struct hv_device *device,
> buf_size = min_t(unsigned int, buf_size,
> NETVSC_RECEIVE_BUFFER_SIZE_LEGACY);
>
> - net_device->recv_buf = vzalloc(buf_size);
> + if (hv_isolation_type_snp()) {
> + net_device->recv_sgt =
> + dma_alloc_noncontiguous(&device->device, buf_size,
> + DMA_FROM_DEVICE, GFP_KERNEL, 0);
> + if (!net_device->recv_sgt) {
> + pr_err("Fail to allocate recv buffer buf_size %d.\n.", buf_size);
> + ret = -ENOMEM;
> + goto cleanup;
> + }
> +
> + net_device->recv_buf = (void *)net_device->recv_sgt->sgl->dma_address;

Use sg_dma_address() macro.

> + } else {
> + net_device->recv_buf = vzalloc(buf_size);
> + }
> +
> if (!net_device->recv_buf) {
> netdev_err(ndev,
> "unable to allocate receive buffer of size %u\n",
> @@ -357,8 +396,6 @@ static int netvsc_init_buf(struct hv_device *device,
> goto cleanup;
> }
>
> - net_device->recv_buf_size = buf_size;
> -
> /*
> * Establish the gpadl handle for this buffer on this
> * channel. Note: This call uses the vmbus connection rather
> @@ -373,6 +410,19 @@ static int netvsc_init_buf(struct hv_device *device,
> goto cleanup;
> }
>
> + if (net_device->recv_sgt) {
> + net_device->recv_buf =
> + dma_vmap_noncontiguous(&device->device, buf_size,
> + net_device->recv_sgt);
> + if (!net_device->recv_buf) {
> + pr_err("Fail to vmap recv buffer.\n");
> + ret = -ENOMEM;
> + goto cleanup;
> + }
> + }
> +
> + net_device->recv_buf_size = buf_size;
> +
> /* Notify the NetVsp of the gpadl handle */
> init_packet = &net_device->channel_init_pkt;
> memset(init_packet, 0, sizeof(struct nvsp_message));
> @@ -454,14 +504,27 @@ static int netvsc_init_buf(struct hv_device *device,
> buf_size = device_info->send_sections * device_info->send_section_size;
> buf_size = round_up(buf_size, PAGE_SIZE);
>
> - net_device->send_buf = vzalloc(buf_size);
> + if (hv_isolation_type_snp()) {
> + net_device->send_sgt =
> + dma_alloc_noncontiguous(&device->device, buf_size,
> + DMA_TO_DEVICE, GFP_KERNEL, 0);
> + if (!net_device->send_sgt) {
> + pr_err("Fail to allocate send buffer buf_size %d.\n.", buf_size);
> + ret = -ENOMEM;
> + goto cleanup;
> + }
> +
> + net_device->send_buf = (void *)net_device->send_sgt->sgl->dma_address;

Use sg_dma_address() macro.

> + } else {
> + net_device->send_buf = vzalloc(buf_size);
> + }
> +
> if (!net_device->send_buf) {
> netdev_err(ndev, "unable to allocate send buffer of size %u\n",
> buf_size);
> ret = -ENOMEM;
> goto cleanup;
> }
> - net_device->send_buf_size = buf_size;
>
> /* Establish the gpadl handle for this buffer on this
> * channel. Note: This call uses the vmbus connection rather
> @@ -476,6 +539,19 @@ static int netvsc_init_buf(struct hv_device *device,
> goto cleanup;
> }
>
> + if (net_device->send_sgt) {
> + net_device->send_buf =
> + dma_vmap_noncontiguous(&device->device, buf_size,
> + net_device->send_sgt);
> + if (!net_device->send_buf) {
> + pr_err("Fail to vmap send buffer.\n");
> + ret = -ENOMEM;
> + goto cleanup;
> + }
> + }
> +
> + net_device->send_buf_size = buf_size;
> +
> /* Notify the NetVsp of the gpadl handle */
> init_packet = &net_device->channel_init_pkt;
> memset(init_packet, 0, sizeof(struct nvsp_message));
> @@ -766,7 +842,7 @@ 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 +858,7 @@ 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 +1023,87 @@ 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.
> + */
> +static 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;
> + }
> +
> + 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;

As noted in comments on an earlier version of this patch, the
pb[i].len and .offset fields should not be changed by doing
dma_map_single(). So there's no need to set them again here. Adding
a comment to that effect might be good.

> + }
> +
> + return 0;
> +}
> +
> static inline int netvsc_send_pkt(
> struct hv_device *device,
> struct hv_netvsc_packet *packet,
> @@ -986,14 +1144,24 @@ 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 +1169,7 @@ static inline int netvsc_send_pkt(
> VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
> }
>
> +exit:
> if (ret == 0) {
> atomic_inc_return(&nvchan->queue_sends);
>
> @@ -1515,13 +1684,6 @@ static int netvsc_process_raw_pkt(struct hv_device *device,
> return 0;
> }
>
> -static struct hv_device *netvsc_channel_to_device(struct vmbus_channel *channel)
> -{
> - struct vmbus_channel *primary = channel->primary_channel;
> -
> - return primary ? primary->device_obj : channel->device_obj;
> -}
> -
> /* Network processing softirq
> * Process data in incoming ring buffer from host
> * Stops when ring is empty or budget is met or exceeded.
> 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/linux/hyperv.h b/include/linux/hyperv.h
> index 4d44fb3b3f1c..8882e46d1070 100644
> --- a/include/linux/hyperv.h
> +++ b/include/linux/hyperv.h
> @@ -25,6 +25,7 @@
> #include <linux/interrupt.h>
> #include <linux/reciprocal_div.h>
> #include <asm/hyperv-tlfs.h>
> +#include <linux/dma-map-ops.h>
>
> #define MAX_PAGE_BUFFER_COUNT 32
> #define MAX_MULTIPAGE_BUFFER_COUNT 32 /* 128K */
> @@ -1583,6 +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

Next message: Suren Baghdasaryan: "Re: [PATCH 1/2] mm: protect free_pgtables with mmap_lock write lock in exit_mmap"
Previous message: Marc Zyngier: "[PATCH v3 0/3] PCI: apple: Assorted #PERST fixes"
In reply to: Tianyu Lan: "[PATCH V2 5/6] net: netvsc: Add Isolation VM support for netvsc driver"
Next in thread: Tianyu Lan: "[PATCH V2 6/6] scsi: storvsc: Add Isolation VM support for storvsc driver"
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