net: netvsc: Add Isolation VM support for netvsc driver

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 <Tianyu.Lan@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20211213071407.314309-6-ltykernel@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>

diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
index 69c7a57..2b99411 100644 (file)
--- 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 7be173a..3c5cb1f 100644 (file)
--- 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 315278a..cf69da0 100644 (file)
--- 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 396bc1c..ea2d867 100644 (file)
--- 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.
+ */
+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;
+               }
+
+               /* 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 7e66ae1..1795853 100644 (file)
--- 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 f6c9c2a..448fcc3 100644 (file)
--- 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 3e2248a..94e73ba 100644 (file)
--- 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 650a057..f565a89 100644 (file)
--- 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,