[Qemu-devel] [PULL 17/21] serial: fixing vmstate for save/restore

[Paolo Bonzini <pbonzini@redhat.com>]

From: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>

Some fields were added to VMState by this patch to preserve correct
loading of the serial port controller state.
Updating FCR value while loading was also modified to disable generating
an interrupt by loadvm.

Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 hw/char/serial.c | 225 +++++++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 195 insertions(+), 30 deletions(-)

diff --git a/hw/char/serial.c b/hw/char/serial.c
index 764e184..a668249 100644
--- a/hw/char/serial.c
+++ b/hw/char/serial.c
@@ -272,6 +272,36 @@ static gboolean serial_xmit(GIOChannel *chan, GIOCondition cond, void *opaque)
 }
 
 
+/* Setter for FCR.
+   is_load flag means, that value is set while loading VM state
+   and interrupt should not be invoked */
+static void serial_write_fcr(SerialState *s, uint8_t val)
+{
+    /* Set fcr - val only has the bits that are supposed to "stick" */
+    s->fcr = val;
+
+    if (val & UART_FCR_FE) {
+        s->iir |= UART_IIR_FE;
+        /* Set recv_fifo trigger Level */
+        switch (val & 0xC0) {
+        case UART_FCR_ITL_1:
+            s->recv_fifo_itl = 1;
+            break;
+        case UART_FCR_ITL_2:
+            s->recv_fifo_itl = 4;
+            break;
+        case UART_FCR_ITL_3:
+            s->recv_fifo_itl = 8;
+            break;
+        case UART_FCR_ITL_4:
+            s->recv_fifo_itl = 14;
+            break;
+        }
+    } else {
+        s->iir &= ~UART_IIR_FE;
+    }
+}
+
 static void serial_ioport_write(void *opaque, hwaddr addr, uint64_t val,
                                 unsigned size)
 {
@@ -327,20 +357,16 @@ static void serial_ioport_write(void *opaque, hwaddr addr, uint64_t val,
         }
         break;
     case 2:
-        val = val & 0xFF;
-
-        if (s->fcr == val)
-            break;
-
         /* Did the enable/disable flag change? If so, make sure FIFOs get flushed */
-        if ((val ^ s->fcr) & UART_FCR_FE)
+        if ((val ^ s->fcr) & UART_FCR_FE) {
             val |= UART_FCR_XFR | UART_FCR_RFR;
+        }
 
         /* FIFO clear */
 
         if (val & UART_FCR_RFR) {
             timer_del(s->fifo_timeout_timer);
-            s->timeout_ipending=0;
+            s->timeout_ipending = 0;
             fifo8_reset(&s->recv_fifo);
         }
 
@@ -348,28 +374,7 @@ static void serial_ioport_write(void *opaque, hwaddr addr, uint64_t val,
             fifo8_reset(&s->xmit_fifo);
         }
 
-        if (val & UART_FCR_FE) {
-            s->iir |= UART_IIR_FE;
-            /* Set recv_fifo trigger Level */
-            switch (val & 0xC0) {
-            case UART_FCR_ITL_1:
-                s->recv_fifo_itl = 1;
-                break;
-            case UART_FCR_ITL_2:
-                s->recv_fifo_itl = 4;
-                break;
-            case UART_FCR_ITL_3:
-                s->recv_fifo_itl = 8;
-                break;
-            case UART_FCR_ITL_4:
-                s->recv_fifo_itl = 14;
-                break;
-            }
-        } else
-            s->iir &= ~UART_IIR_FE;
-
-        /* Set fcr - or at least the bits in it that are supposed to "stick" */
-        s->fcr = val & 0xC9;
+        serial_write_fcr(s, val & 0xC9);
         serial_update_irq(s);
         break;
     case 3:
@@ -590,6 +595,14 @@ static void serial_pre_save(void *opaque)
     s->fcr_vmstate = s->fcr;
 }
 
+static int serial_pre_load(void *opaque)
+{
+    SerialState *s = opaque;
+    s->thr_ipending = -1;
+    s->poll_msl = -1;
+    return 0;
+}
+
 static int serial_post_load(void *opaque, int version_id)
 {
     SerialState *s = opaque;
@@ -597,17 +610,139 @@ static int serial_post_load(void *opaque, int version_id)
     if (version_id < 3) {
         s->fcr_vmstate = 0;
     }
+    if (s->thr_ipending == -1) {
+        s->thr_ipending = ((s->iir & UART_IIR_ID) == UART_IIR_THRI);
+    }
+    s->last_break_enable = (s->lcr >> 6) & 1;
     /* Initialize fcr via setter to perform essential side-effects */
-    serial_ioport_write(s, 0x02, s->fcr_vmstate, 1);
+    serial_write_fcr(s, s->fcr_vmstate);
     serial_update_parameters(s);
     return 0;
 }
 
+static bool serial_thr_ipending_needed(void *opaque)
+{
+    SerialState *s = opaque;
+    bool expected_value = ((s->iir & UART_IIR_ID) == UART_IIR_THRI);
+    return s->thr_ipending != expected_value;
+}
+
+const VMStateDescription vmstate_serial_thr_ipending = {
+    .name = "serial/thr_ipending",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_INT32(thr_ipending, SerialState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static bool serial_tsr_needed(void *opaque)
+{
+    SerialState *s = (SerialState *)opaque;
+    return s->tsr_retry != 0;
+}
+
+const VMStateDescription vmstate_serial_tsr = {
+    .name = "serial/tsr",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_INT32(tsr_retry, SerialState),
+        VMSTATE_UINT8(thr, SerialState),
+        VMSTATE_UINT8(tsr, SerialState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static bool serial_recv_fifo_needed(void *opaque)
+{
+    SerialState *s = (SerialState *)opaque;
+    return !fifo8_is_empty(&s->recv_fifo);
+
+}
+
+const VMStateDescription vmstate_serial_recv_fifo = {
+    .name = "serial/recv_fifo",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_STRUCT(recv_fifo, SerialState, 1, vmstate_fifo8, Fifo8),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static bool serial_xmit_fifo_needed(void *opaque)
+{
+    SerialState *s = (SerialState *)opaque;
+    return !fifo8_is_empty(&s->xmit_fifo);
+}
+
+const VMStateDescription vmstate_serial_xmit_fifo = {
+    .name = "serial/xmit_fifo",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_STRUCT(xmit_fifo, SerialState, 1, vmstate_fifo8, Fifo8),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static bool serial_fifo_timeout_timer_needed(void *opaque)
+{
+    SerialState *s = (SerialState *)opaque;
+    return timer_pending(s->fifo_timeout_timer);
+}
+
+const VMStateDescription vmstate_serial_fifo_timeout_timer = {
+    .name = "serial/fifo_timeout_timer",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_TIMER(fifo_timeout_timer, SerialState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static bool serial_timeout_ipending_needed(void *opaque)
+{
+    SerialState *s = (SerialState *)opaque;
+    return s->timeout_ipending != 0;
+}
+
+const VMStateDescription vmstate_serial_timeout_ipending = {
+    .name = "serial/timeout_ipending",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_INT32(timeout_ipending, SerialState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static bool serial_poll_needed(void *opaque)
+{
+    SerialState *s = (SerialState *)opaque;
+    return s->poll_msl >= 0;
+}
+
+const VMStateDescription vmstate_serial_poll = {
+    .name = "serial/poll",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_INT32(poll_msl, SerialState),
+        VMSTATE_TIMER(modem_status_poll, SerialState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 const VMStateDescription vmstate_serial = {
     .name = "serial",
     .version_id = 3,
     .minimum_version_id = 2,
     .pre_save = serial_pre_save,
+    .pre_load = serial_pre_load,
     .post_load = serial_post_load,
     .fields = (VMStateField[]) {
         VMSTATE_UINT16_V(divider, SerialState, 2),
@@ -621,6 +756,32 @@ const VMStateDescription vmstate_serial = {
         VMSTATE_UINT8(scr, SerialState),
         VMSTATE_UINT8_V(fcr_vmstate, SerialState, 3),
         VMSTATE_END_OF_LIST()
+    },
+    .subsections = (VMStateSubsection[]) {
+        {
+            .vmsd = &vmstate_serial_thr_ipending,
+            .needed = &serial_thr_ipending_needed,
+        } , {
+            .vmsd = &vmstate_serial_tsr,
+            .needed = &serial_tsr_needed,
+        } , {
+            .vmsd = &vmstate_serial_recv_fifo,
+            .needed = &serial_recv_fifo_needed,
+        } , {
+            .vmsd = &vmstate_serial_xmit_fifo,
+            .needed = &serial_xmit_fifo_needed,
+        } , {
+            .vmsd = &vmstate_serial_fifo_timeout_timer,
+            .needed = &serial_fifo_timeout_timer_needed,
+        } , {
+            .vmsd = &vmstate_serial_timeout_ipending,
+            .needed = &serial_timeout_ipending_needed,
+        } , {
+            .vmsd = &vmstate_serial_poll,
+            .needed = &serial_poll_needed,
+        } , {
+            /* empty */
+        }
     }
 };
 
@@ -642,6 +803,10 @@ static void serial_reset(void *opaque)
     s->char_transmit_time = (get_ticks_per_sec() / 9600) * 10;
     s->poll_msl = 0;
 
+    s->timeout_ipending = 0;
+    timer_del(s->fifo_timeout_timer);
+    timer_del(s->modem_status_poll);
+
     fifo8_reset(&s->recv_fifo);
     fifo8_reset(&s->xmit_fifo);
 
-- 
2.1.0