[PATCH 0/8] [GIT PULL] qemu-kvm.git uq/master queue

[PATCH 0/8] [GIT PULL] qemu-kvm.git uq/master queue

[Marcelo Tosatti]

The following changes since commit bf76bafa5ade434ef2747ceeeeaa95510ecb7946:
  Edgar E. Iglesias (1):
        crisv10: Prettify.

are available in the git repository at:

  git://git.kernel.org/pub/scm/virt/kvm/qemu-kvm.git uq/master

Jan Kiszka (1):
      kvm: Fix eflags corruption in kvm mode

Jes Sorensen (1):
      kvm: Kill CR3_CACHE feature references

Marcelo Tosatti (5):
      block SIGCHLD in vcpu thread(s)
      kvm specific wait_io_event
      kvm: consume internal signal with sigtimedwait
      kvm: remove pre-entry exit_request check with iothread enabled
      kvm-all.c: define smp_wmb and use it for coalesced mmio

Paolo Bonzini (1):
      use eventfd for iothread

 cpu-exec.c        |   12 +++--
 kvm-all.c         |   24 ++++++++++-
 kvm.h             |    1 +
 osdep.c           |   32 ++++++++++++++
 qemu-barrier.h    |    7 +++
 qemu-common.h     |    1 +
 target-i386/kvm.c |    3 -
 vl.c              |  123 ++++++++++++++++++++++++++++++++++++++++++++---------
 8 files changed, 173 insertions(+), 30 deletions(-)
 create mode 100644 qemu-barrier.h

[PATCH 1/8] use eventfd for iothread

[Marcelo Tosatti]

From: Paolo Bonzini <pbonzini@redhat.com>

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
 osdep.c       |   32 ++++++++++++++++++++++++++++++++
 qemu-common.h |    1 +
 vl.c          |    9 +++++----
 3 files changed, 38 insertions(+), 4 deletions(-)

diff --git a/osdep.c b/osdep.c
index 9059f01..9e4b17b 100644
--- a/osdep.c
+++ b/osdep.c
@@ -37,6 +37,10 @@
 #include <sys/statvfs.h>
 #endif
 
+#ifdef CONFIG_EVENTFD
+#include <sys/eventfd.h>
+#endif
+
 #ifdef _WIN32
 #include <windows.h>
 #elif defined(CONFIG_BSD)
@@ -281,6 +285,34 @@ ssize_t qemu_write_full(int fd, const void *buf, size_t count)
 
 #ifndef _WIN32
 /*
+ * Creates an eventfd that looks like a pipe and has EFD_CLOEXEC set.
+ */
+int qemu_eventfd(int fds[2])
+{
+    int ret;
+
+#ifdef CONFIG_EVENTFD
+    ret = eventfd(0, 0);
+    if (ret >= 0) {
+        fds[0] = ret;
+        qemu_set_cloexec(ret);
+        if ((fds[1] = dup(ret)) == -1) {
+            close(ret);
+            return -1;
+        }
+        qemu_set_cloexec(fds[1]);
+        return 0;
+    }
+
+    if (errno != ENOSYS) {
+        return -1;
+    }
+#endif
+
+    return qemu_pipe(fds);
+}
+
+/*
  * Creates a pipe with FD_CLOEXEC set on both file descriptors
  */
 int qemu_pipe(int pipefd[2])
diff --git a/qemu-common.h b/qemu-common.h
index b09f717..c941006 100644
--- a/qemu-common.h
+++ b/qemu-common.h
@@ -170,6 +170,7 @@ ssize_t qemu_write_full(int fd, const void *buf, size_t count)
 void qemu_set_cloexec(int fd);
 
 #ifndef _WIN32
+int qemu_eventfd(int pipefd[2]);
 int qemu_pipe(int pipefd[2]);
 #endif
 
diff --git a/vl.c b/vl.c
index 98918ac..1957018 100644
--- a/vl.c
+++ b/vl.c
@@ -3211,14 +3211,15 @@ static int io_thread_fd = -1;
 
 static void qemu_event_increment(void)
 {
-    static const char byte = 0;
+    /* Write 8 bytes to be compatible with eventfd.  */
+    static uint64_t val = 1;
     ssize_t ret;
 
     if (io_thread_fd == -1)
         return;
 
     do {
-        ret = write(io_thread_fd, &byte, sizeof(byte));
+        ret = write(io_thread_fd, &val, sizeof(val));
     } while (ret < 0 && errno == EINTR);
 
     /* EAGAIN is fine, a read must be pending.  */
@@ -3235,7 +3236,7 @@ static void qemu_event_read(void *opaque)
     ssize_t len;
     char buffer[512];
 
-    /* Drain the notify pipe */
+    /* Drain the notify pipe.  For eventfd, only 8 bytes will be read.  */
     do {
         len = read(fd, buffer, sizeof(buffer));
     } while ((len == -1 && errno == EINTR) || len == sizeof(buffer));
@@ -3246,7 +3247,7 @@ static int qemu_event_init(void)
     int err;
     int fds[2];
 
-    err = qemu_pipe(fds);
+    err = qemu_eventfd(fds);
     if (err == -1)
         return -errno;
 
-- 
1.6.6

Re: [PATCH 1/8] use eventfd for iothread

[Pierre Riteau]

When this was merged in qemu-kvm/master (commit 6249f61a891b6b003531ca4e459c3a553faa82bc) it removed Avi's compile fix when !CONFIG_EVENTFD (db311e8619d310bd7729637b702581d3d8565049).
So current master fails to build:
  CC    osdep.o
cc1: warnings being treated as errors
osdep.c: In function 'qemu_eventfd':
osdep.c:296: error: unused variable 'ret'
make: *** [osdep.o] Error 1

On 22 févr. 2010, at 22:26, Marcelo Tosatti wrote:

> From: Paolo Bonzini <pbonzini@redhat.com>
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Avi Kivity <avi@redhat.com>
> ---
> osdep.c       |   32 ++++++++++++++++++++++++++++++++
> qemu-common.h |    1 +
> vl.c          |    9 +++++----
> 3 files changed, 38 insertions(+), 4 deletions(-)
> 
> diff --git a/osdep.c b/osdep.c
> index 9059f01..9e4b17b 100644
> --- a/osdep.c
> +++ b/osdep.c
> @@ -37,6 +37,10 @@
> #include <sys/statvfs.h>
> #endif
> 
> +#ifdef CONFIG_EVENTFD
> +#include <sys/eventfd.h>
> +#endif
> +
> #ifdef _WIN32
> #include <windows.h>
> #elif defined(CONFIG_BSD)
> @@ -281,6 +285,34 @@ ssize_t qemu_write_full(int fd, const void *buf, size_t count)
> 
> #ifndef _WIN32
> /*
> + * Creates an eventfd that looks like a pipe and has EFD_CLOEXEC set.
> + */
> +int qemu_eventfd(int fds[2])
> +{
> +    int ret;
> +
> +#ifdef CONFIG_EVENTFD
> +    ret = eventfd(0, 0);
> +    if (ret >= 0) {
> +        fds[0] = ret;
> +        qemu_set_cloexec(ret);
> +        if ((fds[1] = dup(ret)) == -1) {
> +            close(ret);
> +            return -1;
> +        }
> +        qemu_set_cloexec(fds[1]);
> +        return 0;
> +    }
> +
> +    if (errno != ENOSYS) {
> +        return -1;
> +    }
> +#endif
> +
> +    return qemu_pipe(fds);
> +}
> +
> +/*
>  * Creates a pipe with FD_CLOEXEC set on both file descriptors
>  */
> int qemu_pipe(int pipefd[2])
> diff --git a/qemu-common.h b/qemu-common.h
> index b09f717..c941006 100644
> --- a/qemu-common.h
> +++ b/qemu-common.h
> @@ -170,6 +170,7 @@ ssize_t qemu_write_full(int fd, const void *buf, size_t count)
> void qemu_set_cloexec(int fd);
> 
> #ifndef _WIN32
> +int qemu_eventfd(int pipefd[2]);
> int qemu_pipe(int pipefd[2]);
> #endif
> 
> diff --git a/vl.c b/vl.c
> index 98918ac..1957018 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -3211,14 +3211,15 @@ static int io_thread_fd = -1;
> 
> static void qemu_event_increment(void)
> {
> -    static const char byte = 0;
> +    /* Write 8 bytes to be compatible with eventfd.  */
> +    static uint64_t val = 1;
>     ssize_t ret;
> 
>     if (io_thread_fd == -1)
>         return;
> 
>     do {
> -        ret = write(io_thread_fd, &byte, sizeof(byte));
> +        ret = write(io_thread_fd, &val, sizeof(val));
>     } while (ret < 0 && errno == EINTR);
> 
>     /* EAGAIN is fine, a read must be pending.  */
> @@ -3235,7 +3236,7 @@ static void qemu_event_read(void *opaque)
>     ssize_t len;
>     char buffer[512];
> 
> -    /* Drain the notify pipe */
> +    /* Drain the notify pipe.  For eventfd, only 8 bytes will be read.  */
>     do {
>         len = read(fd, buffer, sizeof(buffer));
>     } while ((len == -1 && errno == EINTR) || len == sizeof(buffer));
> @@ -3246,7 +3247,7 @@ static int qemu_event_init(void)
>     int err;
>     int fds[2];
> 
> -    err = qemu_pipe(fds);
> +    err = qemu_eventfd(fds);
>     if (err == -1)
>         return -errno;
> 
> -- 
> 1.6.6
> 
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

-- 
Pierre Riteau -- PhD student, Myriads team, IRISA, Rennes, France
http://perso.univ-rennes1.fr/pierre.riteau/

[PATCH 2/8] kvm: Fix eflags corruption in kvm mode

[Marcelo Tosatti]

From: Jan Kiszka <jan.kiszka@siemens.com>

This should explain a lot of the weird breakages of upstream KVM we've
seen recently (actually we should have seen it much earlier):

Stop translating eflags into TCG format when in kvm mode as we never
translate it back and rather sync this broken state into the kernel.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
 cpu-exec.c |   12 +++++++-----
 1 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/cpu-exec.c b/cpu-exec.c
index 6a290fd..4029ea2 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -228,11 +228,13 @@ int cpu_exec(CPUState *env1)
     env = env1;
 
 #if defined(TARGET_I386)
-    /* put eflags in CPU temporary format */
-    CC_SRC = env->eflags & (CC_O | CC_S | CC_Z | CC_A | CC_P | CC_C);
-    DF = 1 - (2 * ((env->eflags >> 10) & 1));
-    CC_OP = CC_OP_EFLAGS;
-    env->eflags &= ~(DF_MASK | CC_O | CC_S | CC_Z | CC_A | CC_P | CC_C);
+    if (!kvm_enabled()) {
+        /* put eflags in CPU temporary format */
+        CC_SRC = env->eflags & (CC_O | CC_S | CC_Z | CC_A | CC_P | CC_C);
+        DF = 1 - (2 * ((env->eflags >> 10) & 1));
+        CC_OP = CC_OP_EFLAGS;
+        env->eflags &= ~(DF_MASK | CC_O | CC_S | CC_Z | CC_A | CC_P | CC_C);
+    }
 #elif defined(TARGET_SPARC)
 #elif defined(TARGET_M68K)
     env->cc_op = CC_OP_FLAGS;
-- 
1.6.6

[PATCH 3/8] kvm: Kill CR3_CACHE feature references

[Marcelo Tosatti]

From: Jes Sorensen <Jes.Sorensen@redhat.com>

Remove all references to KVM_CR3_CACHE as it was never implemented.

Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
 target-i386/kvm.c |    3 ---
 1 files changed, 0 insertions(+), 3 deletions(-)

diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index 0d08cd5..5d9aecc 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -158,9 +158,6 @@ struct kvm_para_features {
 #ifdef KVM_CAP_PV_MMU
         { KVM_CAP_PV_MMU, KVM_FEATURE_MMU_OP },
 #endif
-#ifdef KVM_CAP_CR3_CACHE
-        { KVM_CAP_CR3_CACHE, KVM_FEATURE_CR3_CACHE },
-#endif
         { -1, -1 }
 };
 
-- 
1.6.6

[PATCH 4/8] block SIGCHLD in vcpu thread(s)

[Marcelo Tosatti]

Otherwise a vcpu thread can run the sigchild handler causing
waitpid() from iothread to fail.

Signed-off-by: Marcelo Tosatti <mtosa...@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
 vl.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/vl.c b/vl.c
index 1957018..3bc618d 100644
--- a/vl.c
+++ b/vl.c
@@ -3515,6 +3515,7 @@ static void block_io_signals(void)
     sigaddset(&set, SIGUSR2);
     sigaddset(&set, SIGIO);
     sigaddset(&set, SIGALRM);
+    sigaddset(&set, SIGCHLD);
     pthread_sigmask(SIG_BLOCK, &set, NULL);
 
     sigemptyset(&set);
-- 
1.6.6

[PATCH 5/8] kvm specific wait_io_event

[Marcelo Tosatti]

In KVM mode the global mutex is released when vcpus are executing,
which means acquiring the fairness mutex is not required.

Also for KVM there is one thread per vcpu, so tcg_has_work is meaningless.

Add a new qemu_wait_io_event_common function to hold common code
between TCG/KVM.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
 vl.c |   26 ++++++++++++++++++++------
 1 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/vl.c b/vl.c
index 3bc618d..af198c1 100644
--- a/vl.c
+++ b/vl.c
@@ -3383,6 +3383,7 @@ static QemuCond qemu_pause_cond;
 static void block_io_signals(void);
 static void unblock_io_signals(void);
 static int tcg_has_work(void);
+static int cpu_has_work(CPUState *env);
 
 static int qemu_init_main_loop(void)
 {
@@ -3403,6 +3404,15 @@ static int qemu_init_main_loop(void)
     return 0;
 }
 
+static void qemu_wait_io_event_common(CPUState *env)
+{
+    if (env->stop) {
+        env->stop = 0;
+        env->stopped = 1;
+        qemu_cond_signal(&qemu_pause_cond);
+    }
+}
+
 static void qemu_wait_io_event(CPUState *env)
 {
     while (!tcg_has_work())
@@ -3419,11 +3429,15 @@ static void qemu_wait_io_event(CPUState *env)
     qemu_mutex_unlock(&qemu_fair_mutex);
 
     qemu_mutex_lock(&qemu_global_mutex);
-    if (env->stop) {
-        env->stop = 0;
-        env->stopped = 1;
-        qemu_cond_signal(&qemu_pause_cond);
-    }
+    qemu_wait_io_event_common(env);
+}
+
+static void qemu_kvm_wait_io_event(CPUState *env)
+{
+    while (!cpu_has_work(env))
+        qemu_cond_timedwait(env->halt_cond, &qemu_global_mutex, 1000);
+
+    qemu_wait_io_event_common(env);
 }
 
 static int qemu_cpu_exec(CPUState *env);
@@ -3449,7 +3463,7 @@ static void *kvm_cpu_thread_fn(void *arg)
     while (1) {
         if (cpu_can_run(env))
             qemu_cpu_exec(env);
-        qemu_wait_io_event(env);
+        qemu_kvm_wait_io_event(env);
     }
 
     return NULL;
-- 
1.6.6

[PATCH 6/8] kvm: consume internal signal with sigtimedwait

[Marcelo Tosatti]

Change the way the internal qemu signal, used for communication between
iothread and vcpus, is handled.

Block and consume it with sigtimedwait on the outer vcpu loop, which
allows more precise timing control.

Change from standard signal (SIGUSR1) to real-time one, so multiple
signals are not collapsed.

Set the signal number on KVM's in-kernel allowed sigmask.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
 kvm-all.c |   19 +++++++++++++
 kvm.h     |    1 +
 vl.c      |   89 ++++++++++++++++++++++++++++++++++++++++++++++++++++--------
 3 files changed, 97 insertions(+), 12 deletions(-)

diff --git a/kvm-all.c b/kvm-all.c
index 79345b2..38c372f 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -771,6 +771,7 @@ int kvm_cpu_exec(CPUState *env)
         kvm_arch_post_run(env, run);
 
         if (ret == -EINTR || ret == -EAGAIN) {
+            cpu_exit(env);
             dprintf("io window exit\n");
             ret = 0;
             break;
@@ -1116,3 +1117,21 @@ void kvm_remove_all_breakpoints(CPUState *current_env)
 {
 }
 #endif /* !KVM_CAP_SET_GUEST_DEBUG */
+
+int kvm_set_signal_mask(CPUState *env, const sigset_t *sigset)
+{
+    struct kvm_signal_mask *sigmask;
+    int r;
+
+    if (!sigset)
+        return kvm_vcpu_ioctl(env, KVM_SET_SIGNAL_MASK, NULL);
+
+    sigmask = qemu_malloc(sizeof(*sigmask) + sizeof(*sigset));
+
+    sigmask->len = 8;
+    memcpy(sigmask->sigset, sigset, sizeof(*sigset));
+    r = kvm_vcpu_ioctl(env, KVM_SET_SIGNAL_MASK, sigmask);
+    free(sigmask);
+
+    return r;
+}
diff --git a/kvm.h b/kvm.h
index e24bbde..9a9cdd5 100644
--- a/kvm.h
+++ b/kvm.h
@@ -53,6 +53,7 @@ int kvm_remove_breakpoint(CPUState *current_env, target_ulong addr,
                           target_ulong len, int type);
 void kvm_remove_all_breakpoints(CPUState *current_env);
 int kvm_update_guest_debug(CPUState *env, unsigned long reinject_trap);
+int kvm_set_signal_mask(CPUState *env, const sigset_t *sigset);
 
 int kvm_pit_in_kernel(void);
 int kvm_irqchip_in_kernel(void);
diff --git a/vl.c b/vl.c
index af198c1..dc05da3 100644
--- a/vl.c
+++ b/vl.c
@@ -271,6 +271,12 @@ uint8_t qemu_uuid[16];
 static QEMUBootSetHandler *boot_set_handler;
 static void *boot_set_opaque;
 
+#ifdef SIGRTMIN
+#define SIG_IPI (SIGRTMIN+4)
+#else
+#define SIG_IPI SIGUSR1
+#endif
+
 static int default_serial = 1;
 static int default_parallel = 1;
 static int default_virtcon = 1;
@@ -3380,7 +3386,8 @@ static QemuCond qemu_cpu_cond;
 static QemuCond qemu_system_cond;
 static QemuCond qemu_pause_cond;
 
-static void block_io_signals(void);
+static void tcg_block_io_signals(void);
+static void kvm_block_io_signals(CPUState *env);
 static void unblock_io_signals(void);
 static int tcg_has_work(void);
 static int cpu_has_work(CPUState *env);
@@ -3432,11 +3439,36 @@ static void qemu_wait_io_event(CPUState *env)
     qemu_wait_io_event_common(env);
 }
 
+static void qemu_kvm_eat_signal(CPUState *env, int timeout)
+{
+    struct timespec ts;
+    int r, e;
+    siginfo_t siginfo;
+    sigset_t waitset;
+
+    ts.tv_sec = timeout / 1000;
+    ts.tv_nsec = (timeout % 1000) * 1000000;
+
+    sigemptyset(&waitset);
+    sigaddset(&waitset, SIG_IPI);
+
+    qemu_mutex_unlock(&qemu_global_mutex);
+    r = sigtimedwait(&waitset, &siginfo, &ts);
+    e = errno;
+    qemu_mutex_lock(&qemu_global_mutex);
+
+    if (r == -1 && !(e == EAGAIN || e == EINTR)) {
+        fprintf(stderr, "sigtimedwait: %s\n", strerror(e));
+        exit(1);
+    }
+}
+
 static void qemu_kvm_wait_io_event(CPUState *env)
 {
     while (!cpu_has_work(env))
         qemu_cond_timedwait(env->halt_cond, &qemu_global_mutex, 1000);
 
+    qemu_kvm_eat_signal(env, 0);
     qemu_wait_io_event_common(env);
 }
 
@@ -3446,11 +3478,12 @@ static void *kvm_cpu_thread_fn(void *arg)
 {
     CPUState *env = arg;
 
-    block_io_signals();
     qemu_thread_self(env->thread);
     if (kvm_enabled())
         kvm_init_vcpu(env);
 
+    kvm_block_io_signals(env);
+
     /* signal CPU creation */
     qemu_mutex_lock(&qemu_global_mutex);
     env->created = 1;
@@ -3475,7 +3508,7 @@ static void *tcg_cpu_thread_fn(void *arg)
 {
     CPUState *env = arg;
 
-    block_io_signals();
+    tcg_block_io_signals();
     qemu_thread_self(env->thread);
 
     /* signal CPU creation */
@@ -3501,7 +3534,7 @@ void qemu_cpu_kick(void *_env)
     CPUState *env = _env;
     qemu_cond_broadcast(env->halt_cond);
     if (kvm_enabled())
-        qemu_thread_signal(env->thread, SIGUSR1);
+        qemu_thread_signal(env->thread, SIG_IPI);
 }
 
 int qemu_cpu_self(void *_env)
@@ -3520,7 +3553,7 @@ static void cpu_signal(int sig)
         cpu_exit(cpu_single_env);
 }
 
-static void block_io_signals(void)
+static void tcg_block_io_signals(void)
 {
     sigset_t set;
     struct sigaction sigact;
@@ -3533,12 +3566,44 @@ static void block_io_signals(void)
     pthread_sigmask(SIG_BLOCK, &set, NULL);
 
     sigemptyset(&set);
-    sigaddset(&set, SIGUSR1);
+    sigaddset(&set, SIG_IPI);
     pthread_sigmask(SIG_UNBLOCK, &set, NULL);
 
     memset(&sigact, 0, sizeof(sigact));
     sigact.sa_handler = cpu_signal;
-    sigaction(SIGUSR1, &sigact, NULL);
+    sigaction(SIG_IPI, &sigact, NULL);
+}
+
+static void dummy_signal(int sig)
+{
+}
+
+static void kvm_block_io_signals(CPUState *env)
+{
+    int r;
+    sigset_t set;
+    struct sigaction sigact;
+
+    sigemptyset(&set);
+    sigaddset(&set, SIGUSR2);
+    sigaddset(&set, SIGIO);
+    sigaddset(&set, SIGALRM);
+    sigaddset(&set, SIGCHLD);
+    sigaddset(&set, SIG_IPI);
+    pthread_sigmask(SIG_BLOCK, &set, NULL);
+
+    pthread_sigmask(SIG_BLOCK, NULL, &set);
+    sigdelset(&set, SIG_IPI);
+
+    memset(&sigact, 0, sizeof(sigact));
+    sigact.sa_handler = dummy_signal;
+    sigaction(SIG_IPI, &sigact, NULL);
+
+    r = kvm_set_signal_mask(env, &set);
+    if (r) {
+        fprintf(stderr, "kvm_set_signal_mask: %s\n", strerror(r));
+        exit(1);
+    }
 }
 
 static void unblock_io_signals(void)
@@ -3552,7 +3617,7 @@ static void unblock_io_signals(void)
     pthread_sigmask(SIG_UNBLOCK, &set, NULL);
 
     sigemptyset(&set);
-    sigaddset(&set, SIGUSR1);
+    sigaddset(&set, SIG_IPI);
     pthread_sigmask(SIG_BLOCK, &set, NULL);
 }
 
@@ -3561,7 +3626,7 @@ static void qemu_signal_lock(unsigned int msecs)
     qemu_mutex_lock(&qemu_fair_mutex);
 
     while (qemu_mutex_trylock(&qemu_global_mutex)) {
-        qemu_thread_signal(tcg_cpu_thread, SIGUSR1);
+        qemu_thread_signal(tcg_cpu_thread, SIG_IPI);
         if (!qemu_mutex_timedlock(&qemu_global_mutex, msecs))
             break;
     }
@@ -3602,7 +3667,7 @@ static void pause_all_vcpus(void)
 
     while (penv) {
         penv->stop = 1;
-        qemu_thread_signal(penv->thread, SIGUSR1);
+        qemu_thread_signal(penv->thread, SIG_IPI);
         qemu_cpu_kick(penv);
         penv = (CPUState *)penv->next_cpu;
     }
@@ -3611,7 +3676,7 @@ static void pause_all_vcpus(void)
         qemu_cond_timedwait(&qemu_pause_cond, &qemu_global_mutex, 100);
         penv = first_cpu;
         while (penv) {
-            qemu_thread_signal(penv->thread, SIGUSR1);
+            qemu_thread_signal(penv->thread, SIG_IPI);
             penv = (CPUState *)penv->next_cpu;
         }
     }
@@ -3624,7 +3689,7 @@ static void resume_all_vcpus(void)
     while (penv) {
         penv->stop = 0;
         penv->stopped = 0;
-        qemu_thread_signal(penv->thread, SIGUSR1);
+        qemu_thread_signal(penv->thread, SIG_IPI);
         qemu_cpu_kick(penv);
         penv = (CPUState *)penv->next_cpu;
     }
-- 
1.6.6

Re: [Qemu-devel] [PATCH 6/8] kvm: consume internal signal with sigtimedwait

[Andreas Färber]

Hello,

Am 22.02.2010 um 22:26 schrieb Marcelo Tosatti:

> Change the way the internal qemu signal, used for communication  
> between
> iothread and vcpus, is handled.
>
> Block and consume it with sigtimedwait on the outer vcpu loop, which
> allows more precise timing control.

Mac OS X v10.5 does not seem to support sigtimedwait():

   CC    arm-softmmu/cpus.o
/Users/andreas/QEMU/qemu/cpus.c: In function ‘qemu_kvm_eat_signals’:
/Users/andreas/QEMU/qemu/cpus.c:379: warning: implicit declaration of  
function ‘sigtimedwait’
/Users/andreas/QEMU/qemu/cpus.c:379: warning: nested extern  
declaration of ‘sigtimedwait’
/Users/andreas/QEMU/qemu/cpus.c:388: warning: implicit declaration of  
function ‘sigbus_reraise’
/Users/andreas/QEMU/qemu/cpus.c:388: warning: nested extern  
declaration of ‘sigbus_reraise’

Could you please add some #ifdef? It used to be an optional POSIX  
extension.

Thanks,
Andreas

> Change from standard signal (SIGUSR1) to real-time one, so multiple
> signals are not collapsed.
>
> Set the signal number on KVM's in-kernel allowed sigmask.
>
> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
> Signed-off-by: Avi Kivity <avi@redhat.com>
> ---
> kvm-all.c |   19 +++++++++++++
> kvm.h     |    1 +
> vl.c      |   89 +++++++++++++++++++++++++++++++++++++++++++++++++++ 
> +--------
> 3 files changed, 97 insertions(+), 12 deletions(-)

> diff --git a/vl.c b/vl.c
> index af198c1..dc05da3 100644
> --- a/vl.c
> +++ b/vl.c

> @@ -3432,11 +3439,36 @@ static void qemu_wait_io_event(CPUState *env)
>     qemu_wait_io_event_common(env);
> }
>
> +static void qemu_kvm_eat_signal(CPUState *env, int timeout)
> +{
> +    struct timespec ts;
> +    int r, e;
> +    siginfo_t siginfo;
> +    sigset_t waitset;
> +
> +    ts.tv_sec = timeout / 1000;
> +    ts.tv_nsec = (timeout % 1000) * 1000000;
> +
> +    sigemptyset(&waitset);
> +    sigaddset(&waitset, SIG_IPI);
> +
> +    qemu_mutex_unlock(&qemu_global_mutex);
> +    r = sigtimedwait(&waitset, &siginfo, &ts);
> +    e = errno;
> +    qemu_mutex_lock(&qemu_global_mutex);
> +
> +    if (r == -1 && !(e == EAGAIN || e == EINTR)) {
> +        fprintf(stderr, "sigtimedwait: %s\n", strerror(e));
> +        exit(1);
> +    }
> +}

[PATCH] Implement qemu_kvm_eat_signals only for CONFIG_LINUX

[Jan Kiszka]

On 2011-03-06 18:46, Andreas Färber wrote:
> Hello,
> 
> Am 22.02.2010 um 22:26 schrieb Marcelo Tosatti:
> 
>> Change the way the internal qemu signal, used for communication between
>> iothread and vcpus, is handled.
>>
>> Block and consume it with sigtimedwait on the outer vcpu loop, which
>> allows more precise timing control.
> 
> Mac OS X v10.5 does not seem to support sigtimedwait():
> 
>   CC    arm-softmmu/cpus.o
> /Users/andreas/QEMU/qemu/cpus.c: In function ‘qemu_kvm_eat_signals’:
> /Users/andreas/QEMU/qemu/cpus.c:379: warning: implicit declaration of
> function ‘sigtimedwait’
> /Users/andreas/QEMU/qemu/cpus.c:379: warning: nested extern declaration
> of ‘sigtimedwait’
> /Users/andreas/QEMU/qemu/cpus.c:388: warning: implicit declaration of
> function ‘sigbus_reraise’
> /Users/andreas/QEMU/qemu/cpus.c:388: warning: nested extern declaration
> of ‘sigbus_reraise’
> 
> Could you please add some #ifdef? It used to be an optional POSIX
> extension.

This should fix it.

Jan

------8<-------

From: Jan Kiszka <jan.kiszka@siemens.com>

qemu_kvm_eat_signals requires POSIX support with realtime extensions for
sigtimedwait. Not all our target platforms provide this.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
 cpus.c |   94 ++++++++++++++++++++++++++++++++--------------------------------
 1 files changed, 47 insertions(+), 47 deletions(-)

diff --git a/cpus.c b/cpus.c
index 94af696..a10559d 100644
--- a/cpus.c
+++ b/cpus.c
@@ -235,11 +235,58 @@ static void qemu_init_sigbus(void)
     prctl(PR_MCE_KILL, PR_MCE_KILL_SET, PR_MCE_KILL_EARLY, 0, 0);
 }
 
+static void qemu_kvm_eat_signals(CPUState *env)
+{
+    struct timespec ts = { 0, 0 };
+    siginfo_t siginfo;
+    sigset_t waitset;
+    sigset_t chkset;
+    int r;
+
+    sigemptyset(&waitset);
+    sigaddset(&waitset, SIG_IPI);
+    sigaddset(&waitset, SIGBUS);
+
+    do {
+        r = sigtimedwait(&waitset, &siginfo, &ts);
+        if (r == -1 && !(errno == EAGAIN || errno == EINTR)) {
+            perror("sigtimedwait");
+            exit(1);
+        }
+
+        switch (r) {
+        case SIGBUS:
+            if (kvm_on_sigbus_vcpu(env, siginfo.si_code, siginfo.si_addr)) {
+                sigbus_reraise();
+            }
+            break;
+        default:
+            break;
+        }
+
+        r = sigpending(&chkset);
+        if (r == -1) {
+            perror("sigpending");
+            exit(1);
+        }
+    } while (sigismember(&chkset, SIG_IPI) || sigismember(&chkset, SIGBUS));
+
+#ifndef CONFIG_IOTHREAD
+    if (sigismember(&chkset, SIGIO) || sigismember(&chkset, SIGALRM)) {
+        qemu_notify_event();
+    }
+#endif
+}
+
 #else /* !CONFIG_LINUX */
 
 static void qemu_init_sigbus(void)
 {
 }
+
+static void qemu_kvm_eat_signals(CPUState *env)
+{
+}
 #endif /* !CONFIG_LINUX */
 
 #ifndef _WIN32
@@ -364,49 +411,6 @@ static int qemu_signalfd_init(sigset_t mask)
     return 0;
 }
 
-static void qemu_kvm_eat_signals(CPUState *env)
-{
-    struct timespec ts = { 0, 0 };
-    siginfo_t siginfo;
-    sigset_t waitset;
-    sigset_t chkset;
-    int r;
-
-    sigemptyset(&waitset);
-    sigaddset(&waitset, SIG_IPI);
-    sigaddset(&waitset, SIGBUS);
-
-    do {
-        r = sigtimedwait(&waitset, &siginfo, &ts);
-        if (r == -1 && !(errno == EAGAIN || errno == EINTR)) {
-            perror("sigtimedwait");
-            exit(1);
-        }
-
-        switch (r) {
-        case SIGBUS:
-            if (kvm_on_sigbus_vcpu(env, siginfo.si_code, siginfo.si_addr)) {
-                sigbus_reraise();
-            }
-            break;
-        default:
-            break;
-        }
-
-        r = sigpending(&chkset);
-        if (r == -1) {
-            perror("sigpending");
-            exit(1);
-        }
-    } while (sigismember(&chkset, SIG_IPI) || sigismember(&chkset, SIGBUS));
-
-#ifndef CONFIG_IOTHREAD
-    if (sigismember(&chkset, SIGIO) || sigismember(&chkset, SIGALRM)) {
-        qemu_notify_event();
-    }
-#endif
-}
-
 #else /* _WIN32 */
 
 HANDLE qemu_event_handle;
@@ -434,10 +438,6 @@ static void qemu_event_increment(void)
         exit (1);
     }
 }
-
-static void qemu_kvm_eat_signals(CPUState *env)
-{
-}
 #endif /* _WIN32 */
 
 #ifndef CONFIG_IOTHREAD

[PATCH 7/8] kvm: remove pre-entry exit_request check with iothread enabled

[Marcelo Tosatti]

With SIG_IPI blocked vcpu loop exit notification happens via -EAGAIN
from KVM_RUN.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
 kvm-all.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/kvm-all.c b/kvm-all.c
index 38c372f..91d3cbd 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -753,11 +753,13 @@ int kvm_cpu_exec(CPUState *env)
     dprintf("kvm_cpu_exec()\n");
 
     do {
+#ifndef CONFIG_IOTHREAD
         if (env->exit_request) {
             dprintf("interrupt exit requested\n");
             ret = 0;
             break;
         }
+#endif
 
         if (env->kvm_vcpu_dirty) {
             kvm_arch_put_registers(env);
-- 
1.6.6

[PATCH 8/8] kvm-all.c: define smp_wmb and use it for coalesced mmio

[Marcelo Tosatti]

Acked-by: "Michael S. Tsirkin" <mst@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
 kvm-all.c      |    3 ++-
 qemu-barrier.h |    7 +++++++
 2 files changed, 9 insertions(+), 1 deletions(-)
 create mode 100644 qemu-barrier.h

diff --git a/kvm-all.c b/kvm-all.c
index 91d3cbd..1a02076 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -21,6 +21,7 @@
 #include <linux/kvm.h>
 
 #include "qemu-common.h"
+#include "qemu-barrier.h"
 #include "sysemu.h"
 #include "hw/hw.h"
 #include "gdbstub.h"
@@ -730,7 +731,7 @@ void kvm_flush_coalesced_mmio_buffer(void)
             ent = &ring->coalesced_mmio[ring->first];
 
             cpu_physical_memory_write(ent->phys_addr, ent->data, ent->len);
-            /* FIXME smp_wmb() */
+            smp_wmb();
             ring->first = (ring->first + 1) % KVM_COALESCED_MMIO_MAX;
         }
     }
diff --git a/qemu-barrier.h b/qemu-barrier.h
new file mode 100644
index 0000000..3bd1075
--- /dev/null
+++ b/qemu-barrier.h
@@ -0,0 +1,7 @@
+#ifndef __QEMU_BARRIER_H
+#define __QEMU_BARRIER_H 1
+
+/* FIXME: arch dependant, x86 version */
+#define smp_wmb()   asm volatile("" ::: "memory")
+
+#endif
-- 
1.6.6

Re: [PATCH 0/8] [GIT PULL] qemu-kvm.git uq/master queue

[Anthony Liguori]

On 02/22/2010 03:26 PM, Marcelo Tosatti wrote:
> The following changes since commit bf76bafa5ade434ef2747ceeeeaa95510ecb7946:
>    Edgar E. Iglesias (1):
>          crisv10: Prettify.
>
> are available in the git repository at:
>
>    git://git.kernel.org/pub/scm/virt/kvm/qemu-kvm.git uq/master
>
> Jan Kiszka (1):
>        kvm: Fix eflags corruption in kvm mode
>
> Jes Sorensen (1):
>        kvm: Kill CR3_CACHE feature references
>
> Marcelo Tosatti (5):
>        block SIGCHLD in vcpu thread(s)
>        kvm specific wait_io_event
>        kvm: consume internal signal with sigtimedwait
>        kvm: remove pre-entry exit_request check with iothread enabled
>        kvm-all.c: define smp_wmb and use it for coalesced mmio
>
> Paolo Bonzini (1):
>        use eventfd for iothread
>    

Pulled, thanks.

In the future, could you just use a [PULL] tag?  That's what others are 
using.

Regards,

Anthony Liguori

>   cpu-exec.c        |   12 +++--
>   kvm-all.c         |   24 ++++++++++-
>   kvm.h             |    1 +
>   osdep.c           |   32 ++++++++++++++
>   qemu-barrier.h    |    7 +++
>   qemu-common.h     |    1 +
>   target-i386/kvm.c |    3 -
>   vl.c              |  123 ++++++++++++++++++++++++++++++++++++++++++++---------
>   8 files changed, 173 insertions(+), 30 deletions(-)
>   create mode 100644 qemu-barrier.h
>