6.14-stable review patch. If anyone has any objections, please let me know.
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From: Michael Kelley mhklinux@outlook.com
commit 4f98616b855cb0e3b5917918bb07b44728eb96ea upstream.
netvsc currently uses vmbus_sendpacket_pagebuffer() to send VMBus messages. This function creates a series of GPA ranges, each of which contains a single PFN. However, if the rndis header in the VMBus message crosses a page boundary, the netvsc protocol with the host requires that both PFNs for the rndis header must be in a single "GPA range" data structure, which isn't possible with vmbus_sendpacket_pagebuffer(). As the first step in fixing this, add a new function netvsc_build_mpb_array() to build a VMBus message with multiple GPA ranges, each of which may contain multiple PFNs. Use vmbus_sendpacket_mpb_desc() to send this VMBus message to the host.
There's no functional change since higher levels of netvsc don't maintain or propagate knowledge of contiguous PFNs. Based on its input, netvsc_build_mpb_array() still produces a separate GPA range for each PFN and the behavior is the same as with vmbus_sendpacket_pagebuffer(). But the groundwork is laid for a subsequent patch to provide the necessary grouping.
Cc: stable@vger.kernel.org # 6.1.x Signed-off-by: Michael Kelley mhklinux@outlook.com Link: https://patch.msgid.link/20250513000604.1396-3-mhklinux@outlook.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/hyperv/netvsc.c | 50 +++++++++++++++++++++++++++++++++++++++----- 1 file changed, 45 insertions(+), 5 deletions(-)
--- a/drivers/net/hyperv/netvsc.c +++ b/drivers/net/hyperv/netvsc.c @@ -1055,6 +1055,42 @@ static int netvsc_dma_map(struct hv_devi return 0; }
+/* Build an "array" of mpb entries describing the data to be transferred + * over VMBus. After the desc header fields, each "array" entry is variable + * size, and each entry starts after the end of the previous entry. The + * "offset" and "len" fields for each entry imply the size of the entry. + * + * The pfns are in HV_HYP_PAGE_SIZE, because all communication with Hyper-V + * uses that granularity, even if the system page size of the guest is larger. + * Each entry in the input "pb" array must describe a contiguous range of + * guest physical memory so that the pfns are sequential if the range crosses + * a page boundary. The offset field must be < HV_HYP_PAGE_SIZE. + */ +static inline void netvsc_build_mpb_array(struct hv_page_buffer *pb, + u32 page_buffer_count, + struct vmbus_packet_mpb_array *desc, + u32 *desc_size) +{ + struct hv_mpb_array *mpb_entry = &desc->range; + int i, j; + + for (i = 0; i < page_buffer_count; i++) { + u32 offset = pb[i].offset; + u32 len = pb[i].len; + + mpb_entry->offset = offset; + mpb_entry->len = len; + + for (j = 0; j < HVPFN_UP(offset + len); j++) + mpb_entry->pfn_array[j] = pb[i].pfn + j; + + mpb_entry = (struct hv_mpb_array *)&mpb_entry->pfn_array[j]; + } + + desc->rangecount = page_buffer_count; + *desc_size = (char *)mpb_entry - (char *)desc; +} + static inline int netvsc_send_pkt( struct hv_device *device, struct hv_netvsc_packet *packet, @@ -1097,6 +1133,9 @@ static inline int netvsc_send_pkt(
packet->dma_range = NULL; if (packet->page_buf_cnt) { + struct vmbus_channel_packet_page_buffer desc; + u32 desc_size; + if (packet->cp_partial) pb += packet->rmsg_pgcnt;
@@ -1106,11 +1145,12 @@ static inline int netvsc_send_pkt( goto exit; }
- ret = vmbus_sendpacket_pagebuffer(out_channel, - pb, packet->page_buf_cnt, - &nvmsg, sizeof(nvmsg), - req_id); - + netvsc_build_mpb_array(pb, packet->page_buf_cnt, + (struct vmbus_packet_mpb_array *)&desc, + &desc_size); + ret = vmbus_sendpacket_mpb_desc(out_channel, + (struct vmbus_packet_mpb_array *)&desc, + desc_size, &nvmsg, sizeof(nvmsg), req_id); if (ret) netvsc_dma_unmap(ndev_ctx->device_ctx, packet); } else {