From d549db5a732ef2ec145b84c5008a7585cf17cf67 Mon Sep 17 00:00:00 2001 From: Glauber Costa Date: Wed, 7 Oct 2009 16:38:03 -0300 Subject: [PATCH] unlock iothread mutex before running kvm ioctl Without this, kvm will hold the mutex while it issues its run ioctl, and never be able to step out of it, causing a deadlock. Patchworks-ID: 35359 Signed-off-by: Glauber Costa Signed-off-by: Anthony Liguori --- kvm-all.c | 2 ++ qemu-common.h | 3 +++ vl.c | 8 ++++---- 3 files changed, 9 insertions(+), 4 deletions(-) diff --git a/kvm-all.c b/kvm-all.c index 5ea0dd8b1e..48ae26caed 100644 --- a/kvm-all.c +++ b/kvm-all.c @@ -605,7 +605,9 @@ int kvm_cpu_exec(CPUState *env) } kvm_arch_pre_run(env, run); + qemu_mutex_unlock_iothread(); ret = kvm_vcpu_ioctl(env, KVM_RUN, 0); + qemu_mutex_lock_iothread(); kvm_arch_post_run(env, run); if (ret == -EINTR || ret == -EAGAIN) { diff --git a/qemu-common.h b/qemu-common.h index 12e7dd0ada..820dd37a5d 100644 --- a/qemu-common.h +++ b/qemu-common.h @@ -146,6 +146,9 @@ char *qemu_strndup(const char *str, size_t size); void *get_mmap_addr(unsigned long size); +void qemu_mutex_lock_iothread(void); +void qemu_mutex_unlock_iothread(void); + /* Error handling. */ void QEMU_NORETURN hw_error(const char *fmt, ...) diff --git a/vl.c b/vl.c index 374f85be33..afe01af9d7 100644 --- a/vl.c +++ b/vl.c @@ -3560,8 +3560,8 @@ void qemu_notify_event(void) } } -#define qemu_mutex_lock_iothread() do { } while (0) -#define qemu_mutex_unlock_iothread() do { } while (0) +void qemu_mutex_lock_iothread(void) {} +void qemu_mutex_unlock_iothread(void) {} void vm_stop(int reason) { @@ -3760,7 +3760,7 @@ static void qemu_signal_lock(unsigned int msecs) qemu_mutex_unlock(&qemu_fair_mutex); } -static void qemu_mutex_lock_iothread(void) +void qemu_mutex_lock_iothread(void) { if (kvm_enabled()) { qemu_mutex_lock(&qemu_fair_mutex); @@ -3770,7 +3770,7 @@ static void qemu_mutex_lock_iothread(void) qemu_signal_lock(100); } -static void qemu_mutex_unlock_iothread(void) +void qemu_mutex_unlock_iothread(void) { qemu_mutex_unlock(&qemu_global_mutex); }