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hv_netvsc: Use vmbus_sendpacket_mpb_desc() to send VMBus messages

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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>
This commit is contained in:
Michael Kelley
2025-05-12 17:06:01 -07:00
committed by Greg Kroah-Hartman
parent c9d2b9a80d
commit da5d5bc3ad
1 changed files with 45 additions and 5 deletions
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50
drivers/net/hyperv/netvsc.c
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@@ -1047,6 +1047,42 @@ static int netvsc_dma_map(struct hv_device *hv_dev,
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,
@@ -1089,6 +1125,9 @@ 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;
@@ -1098,11 +1137,12 @@ 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 {