From 1882bb1a0967e7d513b0d5bd060fa214bc44efcb Mon Sep 17 00:00:00 2001
From: Fam Zheng <famz@redhat.com>
Date: Fri, 19 May 2017 00:35:15 +0200
Subject: [PATCH 10/18] serial: check if backed by a physical serial port at
 realize time

RH-Author: Fam Zheng <famz@redhat.com>
Message-id: <20170519003523.21163-11-famz@redhat.com>
Patchwork-id: 75366
O-Subject: [RHEL-7.3.z qemu-kvm PATCH 10/18] serial: check if backed by a physical serial port at realize time
Bugzilla: 1452332
RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
RH-Acked-by: Laurent Vivier <lvivier@redhat.com>
RH-Acked-by: Eduardo Habkost <ehabkost@redhat.com>

From: Paolo Bonzini <pbonzini@redhat.com>

Right now, s->poll_msl may linger at "0" value for an arbitrarily long
time, until serial_update_msl is called for the first time.  This is
unnecessary, and will lead to the s->poll_msl field being unnecessarily
migrated.

We can call serial_update_msl immediately at realize time (via
serial_reset) and be done with it.  The memory-mapped UART was already
doing that, but not the ISA and PCI variants.

Regarding the delta bits, be consistent with what serial_reset does when
the serial port is not backed by a physical serial port, and always clear
them at reset time.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit a30cf8760f4a59797fc060c3c5a13b7749551d0c)
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 hw/char/serial.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/hw/char/serial.c b/hw/char/serial.c
index 33e06fb..5ef9b95 100644
--- a/hw/char/serial.c
+++ b/hw/char/serial.c
@@ -650,6 +650,9 @@ static void serial_reset(void *opaque)
     s->thr_ipending = 0;
     s->last_break_enable = 0;
     qemu_irq_lower(s->irq);
+
+    serial_update_msl(s);
+    s->msr &= ~UART_MSR_ANY_DELTA;
 }
 
 void serial_init_core(SerialState *s)
@@ -768,7 +771,5 @@ SerialState *serial_mm_init(MemoryRegion *address_space,
     memory_region_init_io(&s->io, &serial_mm_ops[end], s,
                           "serial", 8 << it_shift);
     memory_region_add_subregion(address_space, base, &s->io);
-
-    serial_update_msl(s);
     return s;
 }
-- 
1.8.3.1