It's a little odd to use signals to raise a notification on a file descriptor
when we can just work directly with a file descriptor instead. This patch
converts the SIGUSR1 based notification in the io-thread to instead use an
eventfd file descriptor.
Signed-off-by: Anthony Liguori <[EMAIL PROTECTED]>
diff --git a/qemu/qemu-kvm.c b/qemu/qemu-kvm.c
index 9a9bf59..7134e56 100644
--- a/qemu/qemu-kvm.c
+++ b/qemu/qemu-kvm.c
@@ -15,6 +15,8 @@ int kvm_pit = 1;
#include <string.h>
#include "hw/hw.h"
#include "sysemu.h"
+#include "qemu-common.h"
+#include "console.h"
#include "qemu-kvm.h"
#include <libkvm.h>
@@ -61,6 +63,7 @@ struct vcpu_info {
} vcpu_info[256];
pthread_t io_thread;
+static int io_thread_fd = -1;
static inline unsigned long kvm_get_thread_id(void)
{
@@ -213,7 +216,7 @@ static int kvm_eat_signal(struct qemu_kvm_signal_table
*waitset, CPUState *env,
if (env && vcpu_info[env->cpu_index].stop) {
vcpu_info[env->cpu_index].stop = 0;
vcpu_info[env->cpu_index].stopped = 1;
- pthread_kill(io_thread, SIGUSR1);
+ qemu_kvm_notify_work();
}
pthread_mutex_unlock(&qemu_mutex);
@@ -418,7 +421,6 @@ static void qemu_kvm_init_signal_tables(void)
kvm_add_signal(&io_signal_table, SIGIO);
kvm_add_signal(&io_signal_table, SIGALRM);
- kvm_add_signal(&io_signal_table, SIGUSR1);
kvm_add_signal(&io_signal_table, SIGUSR2);
kvm_add_signal(&vcpu_signal_table, SIG_IPI);
@@ -440,8 +442,51 @@ int kvm_init_ap(void)
void qemu_kvm_notify_work(void)
{
- if (io_thread)
- pthread_kill(io_thread, SIGUSR1);
+ uint64_t value = 1;
+ char buffer[8];
+ size_t offset = 0;
+
+ if (io_thread_fd == -1)
+ return;
+
+ memcpy(buffer, &value, sizeof(value));
+
+ while (offset < 8) {
+ ssize_t len;
+
+ len = write(io_thread_fd, buffer + offset, 8 - offset);
+ if (len == -1 && errno == EINTR)
+ continue;
+
+ if (len <= 0)
+ break;
+
+ offset += len;
+ }
+
+ if (offset != 8)
+ fprintf(stderr, "failed to notify io thread\n");
+}
+
+/* Used to break IO thread out of select */
+static void io_thread_wakeup(void *opaque)
+{
+ int fd = (unsigned long)opaque;
+ char buffer[8];
+ size_t offset = 0;
+
+ while (offset < 8) {
+ ssize_t len;
+
+ len = read(fd, buffer + offset, 8 - offset);
+ if (len == -1 && errno == EINTR)
+ continue;
+
+ if (len <= 0)
+ break;
+
+ offset += len;
+ }
}
/*
@@ -452,8 +497,20 @@ void qemu_kvm_notify_work(void)
int kvm_main_loop(void)
{
+ int fds[2];
+
io_thread = pthread_self();
qemu_system_ready = 1;
+
+ if (kvm_eventfd(fds) == -1) {
+ fprintf(stderr, "failed to create eventfd\n");
+ return -errno;
+ }
+
+ qemu_set_fd_handler2(fds[0], NULL, io_thread_wakeup, NULL,
+ (void *)(unsigned long)fds[0]);
+
+ io_thread_fd = fds[1];
pthread_mutex_unlock(&qemu_mutex);
pthread_cond_broadcast(&qemu_system_cond);
-------------------------------------------------------------------------
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