Re: [PATCH] do not enter vcpu again if it was stopped during IO
On 06/21/2010 12:01 PM, Gleb Natapov wrote: To prevent reentering vcpu after IO completion it is not enough to set env-stopped since it is checked only in main loop but control will not get there until next non-IO exit since kvm_run() will reenter vcpu to complete IO instruction. Solve this by sending self-signal to request exit after IO instruction completion. Applied, thanks. Does uq/master need such a patch? -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line unsubscribe kvm in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] do not enter vcpu again if it was stopped during IO
On Wed, Jun 23, 2010 at 11:22:15AM +0300, Avi Kivity wrote: On 06/21/2010 12:01 PM, Gleb Natapov wrote: To prevent reentering vcpu after IO completion it is not enough to set env-stopped since it is checked only in main loop but control will not get there until next non-IO exit since kvm_run() will reenter vcpu to complete IO instruction. Solve this by sending self-signal to request exit after IO instruction completion. Applied, thanks. Does uq/master need such a patch? The code is very different there. I looks to me broken too, but the fix will be different. -- Gleb. -- To unsubscribe from this list: send the line unsubscribe kvm in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] do not enter vcpu again if it was stopped during IO
Gleb Natapov wrote:
To prevent reentering vcpu after IO completion it is not enough
to set env-stopped since it is checked only in main loop but control
will not get there until next non-IO exit since kvm_run() will reenter
vcpu to complete IO instruction. Solve this by sending self-signal to
request exit after IO instruction completion.
Signed-off-by: Gleb Natapov g...@redhat.com
diff --git a/qemu-kvm.c b/qemu-kvm.c
index be1dac2..4f7cf6d 100644
--- a/qemu-kvm.c
+++ b/qemu-kvm.c
@@ -603,6 +603,10 @@ int kvm_run(CPUState *env)
r = pre_kvm_run(kvm, env);
if (r)
return r;
+if (env-exit_request) {
+env-exit_request = 0;
+pthread_kill(env-kvm_cpu_state.thread, SIG_IPI);
+}
r = ioctl(fd, KVM_RUN, 0);
if (r == -1 errno != EINTR errno != EAGAIN) {
diff --git a/vl.c b/vl.c
index 9e9c176..dcfab13 100644
--- a/vl.c
+++ b/vl.c
@@ -1817,6 +1817,7 @@ void qemu_system_reset_request(void)
}
if (cpu_single_env) {
cpu_single_env-stopped = 1;
+cpu_exit(cpu_single_env);
}
qemu_notify_event();
}
What does this second hunk do, specifically in the context of I/O
processing? The changelog does not mention it explicitly (or I'm missing
the obvious).
Jan
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Re: [PATCH] do not enter vcpu again if it was stopped during IO
On Wed, Jun 23, 2010 at 12:16:46PM +0200, Jan Kiszka wrote:
Gleb Natapov wrote:
To prevent reentering vcpu after IO completion it is not enough
to set env-stopped since it is checked only in main loop but control
will not get there until next non-IO exit since kvm_run() will reenter
vcpu to complete IO instruction. Solve this by sending self-signal to
request exit after IO instruction completion.
Signed-off-by: Gleb Natapov g...@redhat.com
diff --git a/qemu-kvm.c b/qemu-kvm.c
index be1dac2..4f7cf6d 100644
--- a/qemu-kvm.c
+++ b/qemu-kvm.c
@@ -603,6 +603,10 @@ int kvm_run(CPUState *env)
r = pre_kvm_run(kvm, env);
if (r)
return r;
+if (env-exit_request) {
+env-exit_request = 0;
+pthread_kill(env-kvm_cpu_state.thread, SIG_IPI);
+}
r = ioctl(fd, KVM_RUN, 0);
if (r == -1 errno != EINTR errno != EAGAIN) {
diff --git a/vl.c b/vl.c
index 9e9c176..dcfab13 100644
--- a/vl.c
+++ b/vl.c
@@ -1817,6 +1817,7 @@ void qemu_system_reset_request(void)
}
if (cpu_single_env) {
cpu_single_env-stopped = 1;
+cpu_exit(cpu_single_env);
}
qemu_notify_event();
}
What does this second hunk do, specifically in the context of I/O
processing? The changelog does not mention it explicitly (or I'm missing
the obvious).
It sets env-exit_request. If qemu_system_reset_request() inside io
handler (happens during S3) we should not return to vcpu till resume,
or terrible things will happen. You are probably right that it should
have been send as different patch.
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Re: [PATCH] do not enter vcpu again if it was stopped during IO
On Tue, Jun 22, 2010 at 08:18:14AM +0300, Gleb Natapov wrote:
On Mon, Jun 21, 2010 at 05:43:04PM -0300, Marcelo Tosatti wrote:
On Mon, Jun 21, 2010 at 12:01:52PM +0300, Gleb Natapov wrote:
To prevent reentering vcpu after IO completion it is not enough
to set env-stopped since it is checked only in main loop but control
will not get there until next non-IO exit since kvm_run() will reenter
vcpu to complete IO instruction. Solve this by sending self-signal to
request exit after IO instruction completion.
Signed-off-by: Gleb Natapov g...@redhat.com
diff --git a/qemu-kvm.c b/qemu-kvm.c
index be1dac2..4f7cf6d 100644
--- a/qemu-kvm.c
+++ b/qemu-kvm.c
@@ -603,6 +603,10 @@ int kvm_run(CPUState *env)
r = pre_kvm_run(kvm, env);
if (r)
return r;
+if (env-exit_request) {
+env-exit_request = 0;
+pthread_kill(env-kvm_cpu_state.thread, SIG_IPI);
+}
r = ioctl(fd, KVM_RUN, 0);
Can't you check for env-stopped instead?
Why it would be better? exit_request is used exactly for purpose to
notify cpu loop that is should exit. Sometimes it may be useful to
request cpu exit without stopping the cpu. I see gdbstub uses it, haven't
check if it applicable to kvm though.
Makes sense.
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[PATCH] do not enter vcpu again if it was stopped during IO
To prevent reentering vcpu after IO completion it is not enough
to set env-stopped since it is checked only in main loop but control
will not get there until next non-IO exit since kvm_run() will reenter
vcpu to complete IO instruction. Solve this by sending self-signal to
request exit after IO instruction completion.
Signed-off-by: Gleb Natapov g...@redhat.com
diff --git a/qemu-kvm.c b/qemu-kvm.c
index be1dac2..4f7cf6d 100644
--- a/qemu-kvm.c
+++ b/qemu-kvm.c
@@ -603,6 +603,10 @@ int kvm_run(CPUState *env)
r = pre_kvm_run(kvm, env);
if (r)
return r;
+if (env-exit_request) {
+env-exit_request = 0;
+pthread_kill(env-kvm_cpu_state.thread, SIG_IPI);
+}
r = ioctl(fd, KVM_RUN, 0);
if (r == -1 errno != EINTR errno != EAGAIN) {
diff --git a/vl.c b/vl.c
index 9e9c176..dcfab13 100644
--- a/vl.c
+++ b/vl.c
@@ -1817,6 +1817,7 @@ void qemu_system_reset_request(void)
}
if (cpu_single_env) {
cpu_single_env-stopped = 1;
+cpu_exit(cpu_single_env);
}
qemu_notify_event();
}
--
Gleb.
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Re: [PATCH] do not enter vcpu again if it was stopped during IO
On Mon, Jun 21, 2010 at 12:01:52PM +0300, Gleb Natapov wrote:
To prevent reentering vcpu after IO completion it is not enough
to set env-stopped since it is checked only in main loop but control
will not get there until next non-IO exit since kvm_run() will reenter
vcpu to complete IO instruction. Solve this by sending self-signal to
request exit after IO instruction completion.
Signed-off-by: Gleb Natapov g...@redhat.com
diff --git a/qemu-kvm.c b/qemu-kvm.c
index be1dac2..4f7cf6d 100644
--- a/qemu-kvm.c
+++ b/qemu-kvm.c
@@ -603,6 +603,10 @@ int kvm_run(CPUState *env)
r = pre_kvm_run(kvm, env);
if (r)
return r;
+if (env-exit_request) {
+env-exit_request = 0;
+pthread_kill(env-kvm_cpu_state.thread, SIG_IPI);
+}
r = ioctl(fd, KVM_RUN, 0);
Can't you check for env-stopped instead?
if (r == -1 errno != EINTR errno != EAGAIN) {
diff --git a/vl.c b/vl.c
index 9e9c176..dcfab13 100644
--- a/vl.c
+++ b/vl.c
@@ -1817,6 +1817,7 @@ void qemu_system_reset_request(void)
}
if (cpu_single_env) {
cpu_single_env-stopped = 1;
+cpu_exit(cpu_single_env);
}
qemu_notify_event();
}
--
Gleb.
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Re: [PATCH] do not enter vcpu again if it was stopped during IO
On Mon, Jun 21, 2010 at 05:43:04PM -0300, Marcelo Tosatti wrote:
On Mon, Jun 21, 2010 at 12:01:52PM +0300, Gleb Natapov wrote:
To prevent reentering vcpu after IO completion it is not enough
to set env-stopped since it is checked only in main loop but control
will not get there until next non-IO exit since kvm_run() will reenter
vcpu to complete IO instruction. Solve this by sending self-signal to
request exit after IO instruction completion.
Signed-off-by: Gleb Natapov g...@redhat.com
diff --git a/qemu-kvm.c b/qemu-kvm.c
index be1dac2..4f7cf6d 100644
--- a/qemu-kvm.c
+++ b/qemu-kvm.c
@@ -603,6 +603,10 @@ int kvm_run(CPUState *env)
r = pre_kvm_run(kvm, env);
if (r)
return r;
+if (env-exit_request) {
+env-exit_request = 0;
+pthread_kill(env-kvm_cpu_state.thread, SIG_IPI);
+}
r = ioctl(fd, KVM_RUN, 0);
Can't you check for env-stopped instead?
Why it would be better? exit_request is used exactly for purpose to
notify cpu loop that is should exit. Sometimes it may be useful to
request cpu exit without stopping the cpu. I see gdbstub uses it, haven't
check if it applicable to kvm though.
if (r == -1 errno != EINTR errno != EAGAIN) {
diff --git a/vl.c b/vl.c
index 9e9c176..dcfab13 100644
--- a/vl.c
+++ b/vl.c
@@ -1817,6 +1817,7 @@ void qemu_system_reset_request(void)
}
if (cpu_single_env) {
cpu_single_env-stopped = 1;
+cpu_exit(cpu_single_env);
}
qemu_notify_event();
}
--
Gleb.
--
Gleb.
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