[PATCH] hv_sock: use HV_HYP_PAGE_SIZE instead of PAGE_SIZE_4K

[Himadri Pandya <himadrispandya@gmail.com>]

Older windows hosts require the hv_sock ring buffer to be defined
using 4K pages. This was achieved by using the symbol PAGE_SIZE_4K
defined specifically for this purpose. But now we have a new symbol
HV_HYP_PAGE_SIZE defined in hyperv-tlfs which can be used for this.

This patch removes the definition of symbol PAGE_SIZE_4K and replaces
its usage with the symbol HV_HYP_PAGE_SIZE. This patch also aligns
sndbuf and rcvbuf to hyper-v specific page size using HV_HYP_PAGE_SIZE
instead of the guest page size(PAGE_SIZE) as hyper-v expects the page
size to be 4K and it might not be the case on ARM64 architecture.

Signed-off-by: Himadri Pandya <himadri18.07@gmail.com>
---
 net/vmw_vsock/hyperv_transport.c | 21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/net/vmw_vsock/hyperv_transport.c b/net/vmw_vsock/hyperv_transport.c
index f2084e3f7aa4..ecb5d72d8010 100644
--- a/net/vmw_vsock/hyperv_transport.c
+++ b/net/vmw_vsock/hyperv_transport.c
@@ -13,15 +13,16 @@
 #include <linux/hyperv.h>
 #include <net/sock.h>
 #include <net/af_vsock.h>
+#include <asm/hyperv-tlfs.h>
 
 /* Older (VMBUS version 'VERSION_WIN10' or before) Windows hosts have some
- * stricter requirements on the hv_sock ring buffer size of six 4K pages. Newer
- * hosts don't have this limitation; but, keep the defaults the same for compat.
+ * stricter requirements on the hv_sock ring buffer size of six 4K pages.
+ * hyperv-tlfs defines HV_HYP_PAGE_SIZE as 4K. Newer hosts don't have this
+ * limitation; but, keep the defaults the same for compat.
  */
-#define PAGE_SIZE_4K		4096
-#define RINGBUFFER_HVS_RCV_SIZE (PAGE_SIZE_4K * 6)
-#define RINGBUFFER_HVS_SND_SIZE (PAGE_SIZE_4K * 6)
-#define RINGBUFFER_HVS_MAX_SIZE (PAGE_SIZE_4K * 64)
+#define RINGBUFFER_HVS_RCV_SIZE (HV_HYP_PAGE_SIZE * 6)
+#define RINGBUFFER_HVS_SND_SIZE (HV_HYP_PAGE_SIZE * 6)
+#define RINGBUFFER_HVS_MAX_SIZE (HV_HYP_PAGE_SIZE * 64)
 
 /* The MTU is 16KB per the host side's design */
 #define HVS_MTU_SIZE		(1024 * 16)
@@ -54,7 +55,7 @@ struct hvs_recv_buf {
  * ringbuffer APIs that allow us to directly copy data from userspace buffer
  * to VMBus ringbuffer.
  */
-#define HVS_SEND_BUF_SIZE (PAGE_SIZE_4K - sizeof(struct vmpipe_proto_header))
+#define HVS_SEND_BUF_SIZE (HV_HYP_PAGE_SIZE - sizeof(struct vmpipe_proto_header))
 
 struct hvs_send_buf {
 	/* The header before the payload data */
@@ -388,10 +389,10 @@ static void hvs_open_connection(struct vmbus_channel *chan)
 	} else {
 		sndbuf = max_t(int, sk->sk_sndbuf, RINGBUFFER_HVS_SND_SIZE);
 		sndbuf = min_t(int, sndbuf, RINGBUFFER_HVS_MAX_SIZE);
-		sndbuf = ALIGN(sndbuf, PAGE_SIZE);
+		sndbuf = ALIGN(sndbuf, HV_HYP_PAGE_SIZE);
 		rcvbuf = max_t(int, sk->sk_rcvbuf, RINGBUFFER_HVS_RCV_SIZE);
 		rcvbuf = min_t(int, rcvbuf, RINGBUFFER_HVS_MAX_SIZE);
-		rcvbuf = ALIGN(rcvbuf, PAGE_SIZE);
+		rcvbuf = ALIGN(rcvbuf, HV_HYP_PAGE_SIZE);
 	}
 
 	ret = vmbus_open(chan, sndbuf, rcvbuf, NULL, 0, hvs_channel_cb,
@@ -662,7 +663,7 @@ static ssize_t hvs_stream_enqueue(struct vsock_sock *vsk, struct msghdr *msg,
 	ssize_t ret = 0;
 	ssize_t bytes_written = 0;
 
-	BUILD_BUG_ON(sizeof(*send_buf) != PAGE_SIZE_4K);
+	BUILD_BUG_ON(sizeof(*send_buf) != HV_HYP_PAGE_SIZE);
 
 	send_buf = kmalloc(sizeof(*send_buf), GFP_KERNEL);
 	if (!send_buf)
-- 
2.17.1