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From bf9b8d36996ecbe78f1561404a355af6f7c5d4f6 Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Tue, 21 Jan 2014 11:25:17 -0500
Subject: [PATCH 6/6] qxl: replace pipe signaling with bottom half

Message-id: <1390303517-20167-3-git-send-email-kraxel@redhat.com>
Patchwork-id: 56865
O-Subject: [RHEL-7 qemu-kvm PATCH 2/2] qxl: replace pipe signaling with bottom half
Bugzilla: 1009297
RH-Acked-by: Laszlo Ersek <lersek@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>

qxl creates a pipe, then writes something to it to wake up the iothread
from the spice server thread to raise an irq.  These days qemu bottom
halves can be scheduled from threads and signals, so there is no reason
to do this any more.  Time to clean it up.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
(cherry picked from commit 4a46c99c8118586f19894fe66fc6e353f159d4d9)
---
 hw/display/qxl.c | 33 +++------------------------------
 hw/display/qxl.h |  3 +--
 2 files changed, 4 insertions(+), 32 deletions(-)

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 hw/display/qxl.c | 33 +++------------------------------
 hw/display/qxl.h |  3 +--
 2 files changed, 4 insertions(+), 32 deletions(-)

diff --git a/hw/display/qxl.c b/hw/display/qxl.c
index 830b3c5..4381d97 100644
--- a/hw/display/qxl.c
+++ b/hw/display/qxl.c
@@ -1702,15 +1702,9 @@ static const MemoryRegionOps qxl_io_ops = {
     },
 };
 
-static void pipe_read(void *opaque)
+static void qxl_update_irq_bh(void *opaque)
 {
     PCIQXLDevice *d = opaque;
-    char dummy;
-    int len;
-
-    do {
-        len = read(d->pipe[0], &dummy, sizeof(dummy));
-    } while (len == sizeof(dummy));
     qxl_update_irq(d);
 }
 
@@ -1731,28 +1725,7 @@ static void qxl_send_events(PCIQXLDevice *d, uint32_t events)
     if ((old_pending & le_events) == le_events) {
         return;
     }
-    if (qemu_thread_is_self(&d->main)) {
-        qxl_update_irq(d);
-    } else {
-        if (write(d->pipe[1], d, 1) != 1) {
-            dprint(d, 1, "%s: write to pipe failed\n", __func__);
-        }
-    }
-}
-
-static void init_pipe_signaling(PCIQXLDevice *d)
-{
-    if (pipe(d->pipe) < 0) {
-        fprintf(stderr, "%s:%s: qxl pipe creation failed\n",
-                __FILE__, __func__);
-        exit(1);
-    }
-    fcntl(d->pipe[0], F_SETFL, O_NONBLOCK);
-    fcntl(d->pipe[1], F_SETFL, O_NONBLOCK);
-    fcntl(d->pipe[0], F_SETOWN, getpid());
-
-    qemu_thread_get_self(&d->main);
-    qemu_set_fd_handler(d->pipe[0], pipe_read, NULL, d);
+    qemu_bh_schedule(d->update_irq);
 }
 
 /* graphics console */
@@ -2044,7 +2017,7 @@ static int qxl_init_common(PCIQXLDevice *qxl)
     }
     qemu_add_vm_change_state_handler(qxl_vm_change_state_handler, qxl);
 
-    init_pipe_signaling(qxl);
+    qxl->update_irq = qemu_bh_new(qxl_update_irq_bh, qxl);
     qxl_reset_state(qxl);
 
     qxl->update_area_bh = qemu_bh_new(qxl_render_update_area_bh, qxl);
diff --git a/hw/display/qxl.h b/hw/display/qxl.h
index 8e9b0c2..5da33e2 100644
--- a/hw/display/qxl.h
+++ b/hw/display/qxl.h
@@ -78,8 +78,7 @@ typedef struct PCIQXLDevice {
     QemuMutex          track_lock;
 
     /* thread signaling */
-    QemuThread         main;
-    int                pipe[2];
+    QEMUBH             *update_irq;
 
     /* ram pci bar */
     QXLRam             *ram;
-- 
1.8.3.1