[PATCH V5 12/12] net: netvsc: Add Isolation VM support for netvsc driver

Tianyu Lan
2021-09-14T13:41:31Z

From: Tianyu Lan <Tianyu.Lan@microsoft.com>

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 alloc_pages() in Isolation VM and map
these pages via vmap(). After calling vmbus_establish_gpadl() which
marks these pages visible to host, unmap these pages to release the
virtual address mapped with physical address below shared_gpa_boundary
and map them in the extra address space via vmap_pfn().

Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
---
Change since v4:
* Allocate rx/tx ring buffer via alloc_pages() in Isolation VM
* Map pages after calling vmbus_establish_gpadl().
* set dma_set_min_align_mask for netvsc driver.

Change since v3:
* Add comment to explain why not to use dma_map_sg()
* Fix some error handle.
---
drivers/net/hyperv/hyperv_net.h | 7 +
drivers/net/hyperv/netvsc.c | 287 +++++++++++++++++++++++++++++-
drivers/net/hyperv/netvsc_drv.c | 1 +
drivers/net/hyperv/rndis_filter.c | 2 +
include/linux/hyperv.h | 5 +
5 files changed, 296 insertions(+), 6 deletions(-)

diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index 315278a7cf88..87e8c74398a5 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 +1075,8 @@ struct netvsc_device {

/* Receive buffer allocated by us but manages by NetVSP */
void *recv_buf;
+ struct page **recv_pages;
+ u32 recv_page_count;
u32 recv_buf_size; /* allocated bytes */
struct vmbus_gpadl recv_buf_gpadl_handle;
u32 recv_section_cnt;
@@ -1082,6 +1085,8 @@ struct netvsc_device {

/* Send buffer allocated by us */
void *send_buf;
+ struct page **send_pages;
+ u32 send_page_count;
u32 send_buf_size;
struct vmbus_gpadl send_buf_gpadl_handle;
u32 send_section_cnt;
@@ -1731,4 +1736,6 @@ 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 1f87e570ed2b..7d5254bf043e 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>
@@ -150,11 +151,33 @@ static void free_netvsc_device(struct rcu_head *head)
{
struct netvsc_device *nvdev
= container_of(head, struct netvsc_device, rcu);
+ unsigned int alloc_unit;
int i;

kfree(nvdev->extension);
- vfree(nvdev->recv_buf);
- vfree(nvdev->send_buf);
+
+ if (nvdev->recv_pages) {
+ alloc_unit = (nvdev->recv_buf_size /
+ nvdev->recv_page_count) >> PAGE_SHIFT;
+
+ vunmap(nvdev->recv_buf);
+ for (i = 0; i < nvdev->recv_page_count; i++)
+ __free_pages(nvdev->recv_pages[i], alloc_unit);
+ } else {
+ vfree(nvdev->recv_buf);
+ }
+
+ if (nvdev->send_pages) {
+ alloc_unit = (nvdev->send_buf_size /
+ nvdev->send_page_count) >> PAGE_SHIFT;
+
+ vunmap(nvdev->send_buf);
+ for (i = 0; i < nvdev->send_page_count; i++)
+ __free_pages(nvdev->send_pages[i], alloc_unit);
+ } else {
+ vfree(nvdev->send_buf);
+ }
+
kfree(nvdev->send_section_map);

for (i = 0; i < VRSS_CHANNEL_MAX; i++) {
@@ -330,6 +353,108 @@ int netvsc_alloc_recv_comp_ring(struct netvsc_device *net_device, u32 q_idx)
return nvchan->mrc.slots ? 0 : -ENOMEM;
}

+void *netvsc_alloc_pages(struct page ***pages_array, unsigned int *array_len,
+ unsigned long size)
+{
+ struct page *page, **pages, **vmap_pages;
+ unsigned long pg_count = size >> PAGE_SHIFT;
+ int alloc_unit = MAX_ORDER_NR_PAGES;
+ int i, j, vmap_page_index = 0;
+ void *vaddr;
+
+ if (pg_count < alloc_unit)
+ alloc_unit = 1;
+
+ /* vmap() accepts page array with PAGE_SIZE as unit while try to
+ * allocate high order pages here in order to save page array space.
+ * vmap_pages[] is used as input parameter of vmap(). pages[] is to
+ * store allocated pages and map them later.
+ */
+ vmap_pages = kmalloc_array(pg_count, sizeof(*vmap_pages), GFP_KERNEL);
+ if (!vmap_pages)
+ return NULL;
+
+retry:
+ *array_len = pg_count / alloc_unit;
+ pages = kmalloc_array(*array_len, sizeof(*pages), GFP_KERNEL);
+ if (!pages)
+ goto cleanup;
+
+ for (i = 0; i < *array_len; i++) {
+ page = alloc_pages(GFP_KERNEL | __GFP_ZERO,
+ get_order(alloc_unit << PAGE_SHIFT));
+ if (!page) {
+ /* Try allocating small pages if high order pages are not available. */
+ if (alloc_unit == 1) {
+ goto cleanup;
+ } else {
+ memset(vmap_pages, 0,
+ sizeof(*vmap_pages) * vmap_page_index);
+ vmap_page_index = 0;
+
+ for (j = 0; j < i; j++)
+ __free_pages(pages[j], alloc_unit);
+
+ kfree(pages);
+ alloc_unit = 1;
+ goto retry;
+ }
+ }
+
+ pages[i] = page;
+ for (j = 0; j < alloc_unit; j++)
+ vmap_pages[vmap_page_index++] = page++;
+ }
+
+ vaddr = vmap(vmap_pages, vmap_page_index, VM_MAP, PAGE_KERNEL);
+ kfree(vmap_pages);
+
+ *pages_array = pages;
+ return vaddr;
+
+cleanup:
+ for (j = 0; j < i; j++)
+ __free_pages(pages[i], alloc_unit);
+
+ kfree(pages);
+ kfree(vmap_pages);
+ return NULL;
+}
+
+static void *netvsc_map_pages(struct page **pages, int count, int alloc_unit)
+{
+ int pg_count = count * alloc_unit;
+ struct page *page;
+ unsigned long *pfns;
+ int pfn_index = 0;
+ void *vaddr;
+ int i, j;
+
+ if (!pages)
+ return NULL;
+
+ pfns = kcalloc(pg_count, sizeof(*pfns), GFP_KERNEL);
+ if (!pfns)
+ return NULL;
+
+ for (i = 0; i < count; i++) {
+ page = pages[i];
+ if (!page) {
+ pr_warn("page is not available %d.\n", i);
+ return NULL;
+ }
+
+ for (j = 0; j < alloc_unit; j++) {
+ pfns[pfn_index++] = page_to_pfn(page++) +
+ (ms_hyperv.shared_gpa_boundary >> PAGE_SHIFT);
+ }
+ }
+
+ vaddr = vmap_pfn(pfns, pg_count, PAGE_KERNEL_IO);
+ kfree(pfns);
+ return vaddr;
+}
+
static int netvsc_init_buf(struct hv_device *device,
struct netvsc_device *net_device,
const struct netvsc_device_info *device_info)
@@ -337,7 +462,7 @@ static int netvsc_init_buf(struct hv_device *device,
struct nvsp_1_message_send_receive_buffer_complete *resp;
struct net_device *ndev = hv_get_drvdata(device);
struct nvsp_message *init_packet;
- unsigned int buf_size;
+ unsigned int buf_size, alloc_unit;
size_t map_words;
int i, ret = 0;

@@ -350,7 +475,14 @@ 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_buf =
+ netvsc_alloc_pages(&net_device->recv_pages,
+ &net_device->recv_page_count,
+ buf_size);
+ 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",
@@ -375,6 +507,27 @@ static int netvsc_init_buf(struct hv_device *device,
goto cleanup;
}

+ if (hv_isolation_type_snp()) {
+ alloc_unit = (buf_size / net_device->recv_page_count)
+ >> PAGE_SHIFT;
+
+ /* Unmap previous virtual address and map pages in the extra
+ * address space(above shared gpa boundary) in Isolation VM.
+ */
+ vunmap(net_device->recv_buf);
+ net_device->recv_buf =
+ netvsc_map_pages(net_device->recv_pages,
+ net_device->recv_page_count,
+ alloc_unit);
+ if (!net_device->recv_buf) {
+ netdev_err(ndev,
+ "unable to allocate receive buffer of size %u\n",
+ buf_size);
+ ret = -ENOMEM;
+ goto cleanup;
+ }
+ }
+
/* Notify the NetVsp of the gpadl handle */
init_packet = &net_device->channel_init_pkt;
memset(init_packet, 0, sizeof(struct nvsp_message));
@@ -456,13 +609,21 @@ 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_buf =
+ netvsc_alloc_pages(&net_device->send_pages,
+ &net_device->send_page_count,
+ buf_size);
+ 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
@@ -478,6 +639,27 @@ static int netvsc_init_buf(struct hv_device *device,
goto cleanup;
}

+ if (hv_isolation_type_snp()) {
+ alloc_unit = (buf_size / net_device->send_page_count)
+ >> PAGE_SHIFT;
+
+ /* Unmap previous virtual address and map pages in the extra
+ * address space(above shared gpa boundary) in Isolation VM.
+ */
+ vunmap(net_device->send_buf);
+ net_device->send_buf =
+ netvsc_map_pages(net_device->send_pages,
+ net_device->send_page_count,
+ alloc_unit);
+ if (!net_device->send_buf) {
+ netdev_err(ndev,
+ "unable to allocate receive buffer of size %u\n",
+ buf_size);
+ ret = -ENOMEM;
+ goto cleanup;
+ }
+ }
+
/* Notify the NetVsp of the gpadl handle */
init_packet = &net_device->channel_init_pkt;
memset(init_packet, 0, sizeof(struct nvsp_message));
@@ -768,7 +950,7 @@ 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;
@@ -784,6 +966,7 @@ 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);
}

@@ -948,6 +1131,87 @@ 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,
@@ -988,14 +1252,24 @@ 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),
@@ -1003,6 +1277,7 @@ 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 382bebc2420d..c3dc884b31e3 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -2577,6 +2577,7 @@ static int netvsc_probe(struct hv_device *dev,
list_add(&net_device_ctx->list, &netvsc_dev_list);
rtnl_unlock();

+ dma_set_min_align_mask(&dev->device, HV_HYP_PAGE_SIZE - 1);
netvsc_devinfo_put(device_info);
return 0;

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 c94c534a944e..81e58dd582dc 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -1597,6 +1597,11 @@ 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