e1000: Mask registers when writing

When a register has effective bits fewer than their width, the old code
inconsistently masked when writing or reading. Make the code consistent
by always masking when writing, and remove some code duplication.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
diff --git a/hw/net/e1000.c b/hw/net/e1000.c
index 9619a2e..0925a99 100644
--- a/hw/net/e1000.c
+++ b/hw/net/e1000.c
@@ -1063,30 +1063,6 @@
 }
 
 static uint32_t
-mac_low4_read(E1000State *s, int index)
-{
-    return s->mac_reg[index] & 0xf;
-}
-
-static uint32_t
-mac_low11_read(E1000State *s, int index)
-{
-    return s->mac_reg[index] & 0x7ff;
-}
-
-static uint32_t
-mac_low13_read(E1000State *s, int index)
-{
-    return s->mac_reg[index] & 0x1fff;
-}
-
-static uint32_t
-mac_low16_read(E1000State *s, int index)
-{
-    return s->mac_reg[index] & 0xffff;
-}
-
-static uint32_t
 mac_icr_read(E1000State *s, int index)
 {
     uint32_t ret = s->mac_reg[ICR];
@@ -1138,11 +1114,17 @@
     }
 }
 
-static void
-set_16bit(E1000State *s, int index, uint32_t val)
-{
-    s->mac_reg[index] = val & 0xffff;
-}
+#define LOW_BITS_SET_FUNC(num)                             \
+    static void                                            \
+    set_##num##bit(E1000State *s, int index, uint32_t val) \
+    {                                                      \
+        s->mac_reg[index] = val & (BIT(num) - 1);          \
+    }
+
+LOW_BITS_SET_FUNC(4)
+LOW_BITS_SET_FUNC(11)
+LOW_BITS_SET_FUNC(13)
+LOW_BITS_SET_FUNC(16)
 
 static void
 set_dlen(E1000State *s, int index, uint32_t val)
@@ -1196,7 +1178,9 @@
     getreg(XONRXC),   getreg(XONTXC),   getreg(XOFFRXC),  getreg(XOFFTXC),
     getreg(RFC),      getreg(RJC),      getreg(RNBC),     getreg(TSCTFC),
     getreg(MGTPRC),   getreg(MGTPDC),   getreg(MGTPTC),   getreg(GORCL),
-    getreg(GOTCL),
+    getreg(GOTCL),    getreg(RDFH),     getreg(RDFT),     getreg(RDFHS),
+    getreg(RDFTS),    getreg(RDFPC),    getreg(TDFH),     getreg(TDFT),
+    getreg(TDFHS),    getreg(TDFTS),    getreg(TDFPC),    getreg(AIT),
 
     [TOTH]    = mac_read_clr8,      [TORH]    = mac_read_clr8,
     [GOTCH]   = mac_read_clr8,      [GORCH]   = mac_read_clr8,
@@ -1214,22 +1198,15 @@
     [MPTC]    = mac_read_clr4,
     [ICR]     = mac_icr_read,       [EECD]    = get_eecd,
     [EERD]    = flash_eerd_read,
-    [RDFH]    = mac_low13_read,     [RDFT]    = mac_low13_read,
-    [RDFHS]   = mac_low13_read,     [RDFTS]   = mac_low13_read,
-    [RDFPC]   = mac_low13_read,
-    [TDFH]    = mac_low11_read,     [TDFT]    = mac_low11_read,
-    [TDFHS]   = mac_low13_read,     [TDFTS]   = mac_low13_read,
-    [TDFPC]   = mac_low13_read,
-    [AIT]     = mac_low16_read,
 
     [CRCERRS ... MPC]     = &mac_readreg,
     [IP6AT ... IP6AT + 3] = &mac_readreg,    [IP4AT ... IP4AT + 6] = &mac_readreg,
-    [FFLT ... FFLT + 6]   = &mac_low11_read,
+    [FFLT ... FFLT + 6]   = &mac_readreg,
     [RA ... RA + 31]      = &mac_readreg,
     [WUPM ... WUPM + 31]  = &mac_readreg,
     [MTA ... MTA + 127]   = &mac_readreg,
     [VFTA ... VFTA + 127] = &mac_readreg,
-    [FFMT ... FFMT + 254] = &mac_low4_read,
+    [FFMT ... FFMT + 254] = &mac_readreg,
     [FFVT ... FFVT + 254] = &mac_readreg,
     [PBM ... PBM + 16383] = &mac_readreg,
 };
@@ -1241,26 +1218,27 @@
     putreg(PBA),      putreg(EERD),     putreg(SWSM),     putreg(WUFC),
     putreg(TDBAL),    putreg(TDBAH),    putreg(TXDCTL),   putreg(RDBAH),
     putreg(RDBAL),    putreg(LEDCTL),   putreg(VET),      putreg(FCRUC),
-    putreg(TDFH),     putreg(TDFT),     putreg(TDFHS),    putreg(TDFTS),
-    putreg(TDFPC),    putreg(RDFH),     putreg(RDFT),     putreg(RDFHS),
-    putreg(RDFTS),    putreg(RDFPC),    putreg(IPAV),     putreg(WUC),
-    putreg(WUS),      putreg(AIT),
+    putreg(IPAV),     putreg(WUC),
+    putreg(WUS),
 
-    [TDLEN]  = set_dlen,   [RDLEN]  = set_dlen,       [TCTL] = set_tctl,
-    [TDT]    = set_tctl,   [MDIC]   = set_mdic,       [ICS]  = set_ics,
-    [TDH]    = set_16bit,  [RDH]    = set_16bit,      [RDT]  = set_rdt,
-    [IMC]    = set_imc,    [IMS]    = set_ims,        [ICR]  = set_icr,
-    [EECD]   = set_eecd,   [RCTL]   = set_rx_control, [CTRL] = set_ctrl,
-    [RDTR]   = set_16bit,  [RADV]   = set_16bit,      [TADV] = set_16bit,
-    [ITR]    = set_16bit,
+    [TDLEN]  = set_dlen,   [RDLEN]  = set_dlen,       [TCTL]  = set_tctl,
+    [TDT]    = set_tctl,   [MDIC]   = set_mdic,       [ICS]   = set_ics,
+    [TDH]    = set_16bit,  [RDH]    = set_16bit,      [RDT]   = set_rdt,
+    [IMC]    = set_imc,    [IMS]    = set_ims,        [ICR]   = set_icr,
+    [EECD]   = set_eecd,   [RCTL]   = set_rx_control, [CTRL]  = set_ctrl,
+    [RDTR]   = set_16bit,  [RADV]   = set_16bit,      [TADV]  = set_16bit,
+    [ITR]    = set_16bit,  [TDFH]   = set_11bit,      [TDFT]  = set_11bit,
+    [TDFHS]  = set_13bit,  [TDFTS]  = set_13bit,      [TDFPC] = set_13bit,
+    [RDFH]   = set_13bit,  [RDFT]   = set_13bit,      [RDFHS] = set_13bit,
+    [RDFTS]  = set_13bit,  [RDFPC]  = set_13bit,      [AIT]   = set_16bit,
 
     [IP6AT ... IP6AT + 3] = &mac_writereg, [IP4AT ... IP4AT + 6] = &mac_writereg,
-    [FFLT ... FFLT + 6]   = &mac_writereg,
+    [FFLT ... FFLT + 6]   = &set_11bit,
     [RA ... RA + 31]      = &mac_writereg,
     [WUPM ... WUPM + 31]  = &mac_writereg,
     [MTA ... MTA + 127]   = &mac_writereg,
     [VFTA ... VFTA + 127] = &mac_writereg,
-    [FFMT ... FFMT + 254] = &mac_writereg, [FFVT ... FFVT + 254] = &mac_writereg,
+    [FFMT ... FFMT + 254] = &set_4bit,     [FFVT ... FFVT + 254] = &mac_writereg,
     [PBM ... PBM + 16383] = &mac_writereg,
 };