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From 768dddfbe60ecc3a9a920101aa755804f8a5700e Mon Sep 17 00:00:00 2001
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From: Fam Zheng <famz@redhat.com>
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Date: Thu, 18 May 2017 09:21:31 +0200
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Subject: [PATCH 18/18] serial: remove watch on reset
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RH-Author: Fam Zheng <famz@redhat.com>
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Message-id: <20170518092131.16571-19-famz@redhat.com>
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Patchwork-id: 75308
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O-Subject: [RHEL-7.4 qemu-kvm PATCH v3 18/18] serial: remove watch on reset
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Bugzilla: 1451470
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RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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RH-Acked-by: Eduardo Habkost <ehabkost@redhat.com>
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From: Paolo Bonzini <pbonzini@redhat.com>
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Otherwise, this can cause serial_xmit to be entered with LSR.TEMT=0,
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which is invalid and causes an assertion failure.
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Reported-by: Bret Ketchum <bcketchum@gmail.com>
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Tested-by: Bret Ketchum <bcketchum@gmail.com>
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Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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(cherry picked from commit a1df76da57aa8772a75e7c49f8e3829d07b4c46c)
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Signed-off-by: Fam Zheng <famz@redhat.com>
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 hw/char/serial.c         | 16 ++++++++++++----
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 include/hw/char/serial.h |  1 +
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 2 files changed, 13 insertions(+), 4 deletions(-)
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diff --git a/hw/char/serial.c b/hw/char/serial.c
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index 69fefb2..39de1ca 100644
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--- a/hw/char/serial.c
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+++ b/hw/char/serial.c
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@@ -224,6 +224,7 @@ static gboolean serial_watch_cb(GIOChannel *chan, GIOCondition cond,
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                                 void *opaque)
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 {
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     SerialState *s = opaque;
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+    s->watch_tag = 0;
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     serial_xmit(s);
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     return FALSE;
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 }
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@@ -254,10 +255,12 @@ static void serial_xmit(SerialState *s)
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         if (s->mcr & UART_MCR_LOOP) {
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             /* in loopback mode, say that we just received a char */
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             serial_receive1(s, &s->tsr, 1);
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-        } else if (qemu_chr_fe_write(s->chr, &s->tsr, 1) != 1) {
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-            if (s->tsr_retry < MAX_XMIT_RETRY &&
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-                qemu_chr_fe_add_watch(s->chr, G_IO_OUT|G_IO_HUP,
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-                                      serial_watch_cb, s) > 0) {
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+        } else if (qemu_chr_fe_write(s->chr, &s->tsr, 1) != 1 &&
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+                   s->tsr_retry < MAX_XMIT_RETRY) {
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+            assert(s->watch_tag == 0);
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+            s->watch_tag = qemu_chr_fe_add_watch(s->chr, G_IO_OUT|G_IO_HUP,
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+                                                 serial_watch_cb, s);
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+            if (s->watch_tag > 0) {
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                 s->tsr_retry++;
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                 return;
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             }
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@@ -656,6 +659,11 @@ static void serial_reset(void *opaque)
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 {
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     SerialState *s = opaque;
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+    if (s->watch_tag > 0) {
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+        g_source_remove(s->watch_tag);
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+        s->watch_tag = 0;
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+    }
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+
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     s->rbr = 0;
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     s->ier = 0;
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     s->iir = UART_IIR_NO_INT;
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diff --git a/include/hw/char/serial.h b/include/hw/char/serial.h
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index 2661f8c..19c7763 100644
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--- a/include/hw/char/serial.h
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+++ b/include/hw/char/serial.h
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@@ -56,6 +56,7 @@ struct SerialState {
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     int it_shift;
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     int baudbase;
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     uint32_t tsr_retry;
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+    guint watch_tag;
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     uint32_t wakeup;
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     /* Time when the last byte was successfully sent out of the tsr */
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-- 
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1.8.3.1
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