Resetting guests used to be racy, deadlock-prone, or simply broken (for
SMP). This patch fixes the issues, following Marcelo's suggestion to
consolidate the reset activity in the I/O thread. All vcpus are cleanly
stopped before the emulated hardware is reset, and kvm_arch_cpu_reset is
introduced and invoked to ensure that non-boot cpus are put into the
right state on x86. Note that other arch may need to look into this
service as well to get SMP reset right.
Moreover, a safety check is added to pause/resume_all_threads to ensure
that they are only invoked in I/O thread context.
Signed-off-by: Jan Kiszka <[EMAIL PROTECTED]>
---
qemu/qemu-kvm-ia64.c | 4 ++++
qemu/qemu-kvm-powerpc.c | 4 ++++
qemu/qemu-kvm-x86.c | 16 ++++++++++++++++
qemu/qemu-kvm.c | 34 +++++++++++++++++-----------------
qemu/qemu-kvm.h | 1 +
qemu/vl.c | 6 +-----
6 files changed, 43 insertions(+), 22 deletions(-)
Index: b/qemu/qemu-kvm-ia64.c
===================================================================
--- a/qemu/qemu-kvm-ia64.c
+++ b/qemu/qemu-kvm-ia64.c
@@ -61,3 +61,7 @@ int kvm_arch_try_push_interrupts(void *o
void kvm_arch_update_regs_for_sipi(CPUState *env)
{
}
+
+void kvm_arch_cpu_reset(CPUState *env)
+{
+}
Index: b/qemu/qemu-kvm-powerpc.c
===================================================================
--- a/qemu/qemu-kvm-powerpc.c
+++ b/qemu/qemu-kvm-powerpc.c
@@ -213,3 +213,7 @@ int handle_powerpc_dcr_write(int vcpu, u
return 0; /* XXX ignore failed DCR ops */
}
+
+void kvm_arch_cpu_reset(CPUState *env)
+{
+}
Index: b/qemu/qemu-kvm-x86.c
===================================================================
--- a/qemu/qemu-kvm-x86.c
+++ b/qemu/qemu-kvm-x86.c
@@ -671,3 +671,19 @@ int handle_tpr_access(void *opaque, int
kvm_tpr_access_report(cpu_single_env, rip, is_write);
return 0;
}
+
+void kvm_arch_cpu_reset(CPUState *env)
+{
+ struct kvm_mp_state mp_state = { .mp_state = KVM_MP_STATE_UNINITIALIZED };
+
+ kvm_arch_load_regs(env);
+ if (env->cpu_index != 0) {
+ if (kvm_irqchip_in_kernel(kvm_context))
+ kvm_set_mpstate(kvm_context, env->cpu_index, &mp_state);
+ else {
+ env->interrupt_request &= ~CPU_INTERRUPT_HARD;
+ env->hflags |= HF_HALTED_MASK;
+ env->exception_index = EXCP_HLT;
+ }
+ }
+}
Index: b/qemu/qemu-kvm.c
===================================================================
--- a/qemu/qemu-kvm.c
+++ b/qemu/qemu-kvm.c
@@ -32,8 +32,6 @@ kvm_context_t kvm_context;
extern int smp_cpus;
-static int qemu_kvm_reset_requested;
-
pthread_mutex_t qemu_mutex = PTHREAD_MUTEX_INITIALIZER;
pthread_cond_t qemu_aio_cond = PTHREAD_COND_INITIALIZER;
pthread_cond_t qemu_vcpu_cond = PTHREAD_COND_INITIALIZER;
@@ -53,7 +51,6 @@ struct vcpu_info {
int signalled;
int stop;
int stopped;
- int reload_regs;
int created;
} vcpu_info[256];
@@ -251,6 +248,8 @@ static void pause_all_threads(void)
{
int i;
+ assert(!cpu_single_env);
+
for (i = 0; i < smp_cpus; ++i) {
vcpu_info[i].stop = 1;
pthread_kill(vcpu_info[i].thread, SIG_IPI);
@@ -263,6 +262,8 @@ static void resume_all_threads(void)
{
int i;
+ assert(!cpu_single_env);
+
for (i = 0; i < smp_cpus; ++i) {
vcpu_info[i].stop = 0;
vcpu_info[i].stopped = 0;
@@ -307,15 +308,18 @@ static void setup_kernel_sigmask(CPUStat
kvm_set_signal_mask(kvm_context, env->cpu_index, &set);
}
-void qemu_kvm_system_reset_request(void)
+void qemu_kvm_system_reset(void)
{
int i;
- for (i = 0; i < smp_cpus; ++i) {
- vcpu_info[i].reload_regs = 1;
- pthread_kill(vcpu_info[i].thread, SIG_IPI);
- }
+ pause_all_threads();
+
qemu_system_reset();
+
+ for (i = 0; i < smp_cpus; ++i)
+ kvm_arch_cpu_reset(vcpu_info[i].env);
+
+ resume_all_threads();
}
static int kvm_main_loop_cpu(CPUState *env)
@@ -348,11 +352,6 @@ static int kvm_main_loop_cpu(CPUState *e
kvm_cpu_exec(env);
env->interrupt_request &= ~CPU_INTERRUPT_EXIT;
kvm_main_loop_wait(env, 0);
- if (info->reload_regs) {
- info->reload_regs = 0;
- if (env->cpu_index == 0) /* ap needs to be placed in INIT */
- kvm_arch_load_regs(env);
- }
}
pthread_mutex_unlock(&qemu_mutex);
return 0;
@@ -535,10 +534,8 @@ int kvm_main_loop(void)
break;
else if (qemu_powerdown_requested())
qemu_system_powerdown();
- else if (qemu_reset_requested()) {
- pthread_kill(vcpu_info[0].thread, SIG_IPI);
- qemu_kvm_reset_requested = 1;
- }
+ else if (qemu_reset_requested())
+ qemu_kvm_system_reset();
}
pause_all_threads();
@@ -647,6 +644,9 @@ static int kvm_halt(void *opaque, int vc
static int kvm_shutdown(void *opaque, int vcpu)
{
+ /* stop the current vcpu from going back to guest mode */
+ vcpu_info[cpu_single_env->cpu_index].stopped = 1;
+
qemu_system_reset_request();
return 1;
}
Index: b/qemu/qemu-kvm.h
===================================================================
--- a/qemu/qemu-kvm.h
+++ b/qemu/qemu-kvm.h
@@ -59,6 +59,7 @@ void kvm_arch_post_kvm_run(void *opaque,
int kvm_arch_has_work(CPUState *env);
int kvm_arch_try_push_interrupts(void *opaque);
void kvm_arch_update_regs_for_sipi(CPUState *env);
+void kvm_arch_cpu_reset(CPUState *env);
CPUState *qemu_kvm_cpu_env(int index);
Index: b/qemu/vl.c
===================================================================
--- a/qemu/vl.c
+++ b/qemu/vl.c
@@ -7302,11 +7302,7 @@ void qemu_system_reset_request(void)
}
if (cpu_single_env)
cpu_interrupt(cpu_single_env, CPU_INTERRUPT_EXIT);
-#ifdef USE_KVM
- if (kvm_allowed)
- if (!no_reboot)
- qemu_kvm_system_reset_request();
-#endif
+ main_loop_break();
}
void qemu_system_shutdown_request(void)
-------------------------------------------------------------------------
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