[PATCH v4 1/3] hw/net: e1000: Correct the initial value of VET register

[Bin Meng]

From: Christina Wang <christina.wang@windriver.com>

The initial value of VLAN Ether Type (VET) register is 0x8100, as per
the manual and real hardware.

While Linux e1000 driver always writes VET register to 0x8100, it is
not always the case for everyone. Drivers relying on the reset value
of VET won't be able to transmit and receive VLAN frames in QEMU.

Reported-by: Markus Carlstedt <markus.carlstedt@windriver.com>
Signed-off-by: Christina Wang <christina.wang@windriver.com>
Signed-off-by: Bin Meng <bin.meng@windriver.com>

---

Changes in v4:
- Only keep hw_compat_6_0[] changes
- Use e1000_vet_init_need() instead of touching other flags

Changes in v3:
- add a "init-vet" property for versioned machines

 hw/core/machine.c |  1 +
 hw/net/e1000.c    | 17 +++++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/hw/core/machine.c b/hw/core/machine.c
index 775add0795..f98a797e43 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -41,6 +41,7 @@ GlobalProperty hw_compat_6_0[] = {
     { "gpex-pcihost", "allow-unmapped-accesses", "false" },
     { "i8042", "extended-state", "false"},
     { "nvme-ns", "eui64-default", "off"},
+    { "e1000", "init-vet", "off" },
 };
 const size_t hw_compat_6_0_len = G_N_ELEMENTS(hw_compat_6_0);
 
diff --git a/hw/net/e1000.c b/hw/net/e1000.c
index 4f75b44cfc..a30546c5d5 100644
--- a/hw/net/e1000.c
+++ b/hw/net/e1000.c
@@ -29,6 +29,7 @@
 #include "hw/pci/pci.h"
 #include "hw/qdev-properties.h"
 #include "migration/vmstate.h"
+#include "net/eth.h"
 #include "net/net.h"
 #include "net/checksum.h"
 #include "sysemu/sysemu.h"
@@ -130,10 +131,13 @@ struct E1000State_st {
 #define E1000_FLAG_MIT_BIT 1
 #define E1000_FLAG_MAC_BIT 2
 #define E1000_FLAG_TSO_BIT 3
+#define E1000_FLAG_VET_BIT 4
 #define E1000_FLAG_AUTONEG (1 << E1000_FLAG_AUTONEG_BIT)
 #define E1000_FLAG_MIT (1 << E1000_FLAG_MIT_BIT)
 #define E1000_FLAG_MAC (1 << E1000_FLAG_MAC_BIT)
 #define E1000_FLAG_TSO (1 << E1000_FLAG_TSO_BIT)
+#define E1000_FLAG_VET (1 << E1000_FLAG_VET_BIT)
+
     uint32_t compat_flags;
     bool received_tx_tso;
     bool use_tso_for_migration;
@@ -361,6 +365,13 @@ e1000_autoneg_timer(void *opaque)
     }
 }
 
+static bool e1000_vet_init_need(void *opaque)
+{
+    E1000State *s = opaque;
+
+    return chkflag(VET);
+}
+
 static void e1000_reset(void *opaque)
 {
     E1000State *d = opaque;
@@ -386,6 +397,10 @@ static void e1000_reset(void *opaque)
     }
 
     e1000x_reset_mac_addr(d->nic, d->mac_reg, macaddr);
+
+    if (e1000_vet_init_need(d)) {
+        d->mac_reg[VET] = ETH_P_VLAN;
+    }
 }
 
 static void
@@ -1737,6 +1752,8 @@ static Property e1000_properties[] = {
                     compat_flags, E1000_FLAG_MAC_BIT, true),
     DEFINE_PROP_BIT("migrate_tso_props", E1000State,
                     compat_flags, E1000_FLAG_TSO_BIT, true),
+    DEFINE_PROP_BIT("init-vet", E1000State,
+                    compat_flags, E1000_FLAG_VET_BIT, true),
     DEFINE_PROP_END_OF_LIST(),
 };
 
-- 
2.25.1