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

Tianyu Lan
2021-11-23T14:37:16Z

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@microsoft.com>
---
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;
+ } 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;
+ } 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;
+ }
+
+ 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