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>

hw/net/e1000.c

@@ -1062,30 +1062,6 @@ mac_readreg(E1000State *s, int index)
     return s->mac_reg[index];
 }
 
-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)
 {
@@ -1138,11 +1114,17 @@ set_rdt(E1000State *s, int index, uint32_t val)
     }
 }
 
-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 @@ static const readops macreg_readops[] = {
     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 @@ static const readops macreg_readops[] = {
     [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 @@ static const writeops macreg_writeops[] = {
     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),
-
-    [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,
+    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,  [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,
 };