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authorAnton Blanchard <anton@samba.org>2014-08-22 11:50:57 +1000
committerAlexander Graf <agraf@suse.de>2014-09-08 12:50:52 +0200
commit439ce1401bac1687c711cb6acf4ee8f3f457c05e (patch)
tree3192a4e751af6404bcb3de01c35fe2aa2db6da0b /hw/net
parent32420522482ffc20f8e9423af4f41f4e05ce3a56 (diff)
downloadqemu-439ce1401bac1687c711cb6acf4ee8f3f457c05e.tar.gz
spapr-vlan: Don't touch last entry in buffer list
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 <anton@samba.org> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Alexander Graf <agraf@suse.de>
Diffstat (limited to 'hw/net')
-rw-r--r--hw/net/spapr_llan.c13
1 files changed, 10 insertions, 3 deletions
diff --git a/hw/net/spapr_llan.c b/hw/net/spapr_llan.c
index 2d47df6930..23c47d397c 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;
}