On 10/04/2011 03:47 PM, Christian Borntraeger wrote:
Something like the following?
s390: Fix cpu shutdown for KVM
On s390 a shutdown is the state of all CPUs being either stopped
or disabled (for interrupts) waiting. We have to track this number
to call the shutdown sequence accordingly. This patch implements
the counting and shutdown handling for the kvm path in qemu.
Signed-off-by: Christian Borntraeger<borntrae...@de.ibm.com>
---
hw/s390-virtio.c | 21 +++++++++++++++++++++
target-s390x/cpu.h | 12 ++++++++++++
target-s390x/kvm.c | 21 +++++++++++++++++----
3 files changed, 50 insertions(+), 4 deletions(-)
Index: b/hw/s390-virtio.c
===================================================================
--- a/hw/s390-virtio.c
+++ b/hw/s390-virtio.c
@@ -130,6 +130,26 @@ int s390_virtio_hypercall(CPUState *env,
return r;
}
+/*
+ * The number of running CPUs. On s390 a shutdown is the state of all CPUs
+ * being either stopped or disabled (for interrupts) waiting. We have to
+ * track this number to call the shutdown sequence accordingly. This
+ * number is modified either on startup or while holding the big qemu lock.
+ */
+static unsigned s390_running_cpus;
+
+void kvm_s390_add_running_cpu(CPUState *env)
+{
+ assert(env->halted == 0);
+ s390_running_cpus++;
+}
+
+unsigned kvm_s390_del_running_cpu(CPUState *env)
+{
+ assert(s390_running_cpus>= 1);
+ return --s390_running_cpus;
+}
Almost. It has nothing to do with KVM though. Please keep the
abstraction intact!
+
/* PC hardware initialisation */
static void s390_init(ram_addr_t my_ram_size,
const char *boot_device,
@@ -189,6 +209,7 @@ static void s390_init(ram_addr_t my_ram_
env->halted = 0;
env->exception_index = 0;
+ kvm_s390_add_running_cpu(env);
if (kernel_filename) {
kernel_size = load_image(kernel_filename, qemu_get_ram_ptr(0));
Index: b/target-s390x/cpu.h
===================================================================
--- a/target-s390x/cpu.h
+++ b/target-s390x/cpu.h
@@ -292,6 +292,8 @@ void kvm_s390_interrupt(CPUState *env, i
void kvm_s390_virtio_irq(CPUState *env, int config_change, uint64_t token);
void kvm_s390_interrupt_internal(CPUState *env, int type, uint32_t parm,
uint64_t parm64, int vm);
+void kvm_s390_add_running_cpu(CPUState *env);
+unsigned kvm_s390_del_running_cpu(CPUState *env);
#else
static inline void kvm_s390_interrupt(CPUState *env, int type, uint32_t code)
{
@@ -307,6 +309,16 @@ static inline void kvm_s390_interrupt_in
int vm)
{
}
+
+static inline void kvm_s390_add_running_cpu(CPUState *env)
+{
+}
+
+static inline unsigned kvm_s390_del_running_cpu(CPUState *env)
+{
+ return 0;
+}
The functions are defined in s390-virtio.c and thus are available
anywhere now. No need to special-case KVM anywhere.
+
#endif
CPUState *s390_cpu_addr2state(uint16_t cpu_addr);
Index: b/target-s390x/kvm.c
===================================================================
--- a/target-s390x/kvm.c
+++ b/target-s390x/kvm.c
@@ -185,6 +185,12 @@ void kvm_s390_interrupt_internal(CPUStat
return;
}
+ /*
+ * We can only deliver interrupts to (interrupt) enabled CPUs.
+ * We dont call kvm_s390_add_running_cpu here, since CPUs in enabled wait
+ * will wait inside the kernel (no exit). Therefore, the targeted
+ * CPUs was neither disabled waiting or stopped for qemu.
+ */
env->halted = 0;
env->exception_index = -1;
qemu_cpu_kick(env);
@@ -301,6 +307,7 @@ static int s390_cpu_restart(CPUState *en
kvm_s390_interrupt(env, KVM_S390_RESTART, 0);
env->halted = 0;
env->exception_index = -1;
+ kvm_s390_add_running_cpu(env);
Hrm. Is add_running correct here? Maybe we should add a wrapper around
the halted = 0 parts in s390-virtio.c and do the increase of the counter
there? That way we can make sure that transitioning from 0 -> 0 doesn't
increase the counter.
Alex
