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[Qemu-devel] [PATCH] spapr-vlan: Don't touch last entry in buffer list
From: |
Anton Blanchard |
Subject: |
[Qemu-devel] [PATCH] spapr-vlan: Don't touch last entry in buffer list |
Date: |
Fri, 22 Aug 2014 11:50:57 +1000 |
The last 8 bytes of the buffer list is defined to contain the number
of dropped frames. At the moment we use it to store rx entries,
which trips up ethtool -S:
rx_no_buffer: 9223380832981355136
Fix this by skipping the last buffer list entry.
Signed-off-by: Anton Blanchard <address@hidden>
---
diff --git a/hw/net/spapr_llan.c b/hw/net/spapr_llan.c
index 2d47df6..23c47d3 100644
--- a/hw/net/spapr_llan.c
+++ b/hw/net/spapr_llan.c
@@ -72,7 +72,14 @@ typedef uint64_t vlan_bd_t;
#define VLAN_RXQ_BD_OFF 0
#define VLAN_FILTER_BD_OFF 8
#define VLAN_RX_BDS_OFF 16
-#define VLAN_MAX_BUFS ((SPAPR_TCE_PAGE_SIZE - VLAN_RX_BDS_OFF) / 8)
+/*
+ * The final 8 bytes of the buffer list is a counter of frames dropped
+ * because there was not a buffer in the buffer list capable of holding
+ * the frame. We must avoid it, or the operating system will report garbage
+ * for this statistic.
+ */
+#define VLAN_RX_BDS_LEN (SPAPR_TCE_PAGE_SIZE - VLAN_RX_BDS_OFF - 8)
+#define VLAN_MAX_BUFS (VLAN_RX_BDS_LEN / 8)
#define TYPE_VIO_SPAPR_VLAN_DEVICE "spapr-vlan"
#define VIO_SPAPR_VLAN_DEVICE(obj) \
@@ -119,7 +126,7 @@ static ssize_t spapr_vlan_receive(NetClientState *nc, const
uint8_t *buf,
do {
buf_ptr += 8;
- if (buf_ptr >= SPAPR_TCE_PAGE_SIZE) {
+ if (buf_ptr >= (VLAN_RX_BDS_LEN + VLAN_RX_BDS_OFF)) {
buf_ptr = VLAN_RX_BDS_OFF;
}
@@ -397,7 +404,7 @@ static target_ulong h_add_logical_lan_buffer(PowerPCCPU
*cpu,
do {
dev->add_buf_ptr += 8;
- if (dev->add_buf_ptr >= SPAPR_TCE_PAGE_SIZE) {
+ if (dev->add_buf_ptr >= (VLAN_RX_BDS_LEN + VLAN_RX_BDS_OFF)) {
dev->add_buf_ptr = VLAN_RX_BDS_OFF;
}
- [Qemu-devel] [PATCH] spapr-vlan: Don't touch last entry in buffer list,
Anton Blanchard <=