On 2013-04-25 11:06, Alexander Graf wrote:
> On PPC, we don't support MP state. So far it's not necessary and I'm
> not convinced yet that we really need to support it ever.
>
> However, the current idle logic in QEMU assumes that an in-kernel PIC
> also means we support MP state. This assumption is not true anymore.
>
> Let's split up the two cases into two different variables. That way
> PPC can expose an in-kernel PIC, while not implementing MP state.
>
> Signed-off-by: Alexander Graf <ag...@suse.de>
> CC: Jan Kiszka <jan.kis...@siemens.com>
>
> ---
>
> v1 -> v2:
>
> - use kvm_halt_in_kernel() instead
> ---
> cpus.c | 2 +-
> include/sysemu/kvm.h | 10 ++++++++++
> kvm-all.c | 2 ++
> 3 files changed, 13 insertions(+), 1 deletions(-)
>
> diff --git a/cpus.c b/cpus.c
> index e919dd7..e626f7e 100644
> --- a/cpus.c
> +++ b/cpus.c
> @@ -73,7 +73,7 @@ static bool cpu_thread_is_idle(CPUArchState *env)
> return true;
> }
> if (!cpu->halted || qemu_cpu_has_work(cpu) ||
> - kvm_async_interrupts_enabled()) {
> + kvm_halt_in_kernel()) {
> return false;
> }
> return true;
> diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
> index 8a9ebda..07375bf 100644
> --- a/include/sysemu/kvm.h
> +++ b/include/sysemu/kvm.h
> @@ -42,6 +42,7 @@
> extern bool kvm_allowed;
> extern bool kvm_kernel_irqchip;
> extern bool kvm_async_interrupts_allowed;
> +extern bool kvm_halt_in_kernel_allowed;
> extern bool kvm_irqfds_allowed;
> extern bool kvm_msi_via_irqfd_allowed;
> extern bool kvm_gsi_routing_allowed;
> @@ -72,6 +73,14 @@ extern bool kvm_gsi_routing_allowed;
> #define kvm_async_interrupts_enabled() (kvm_async_interrupts_allowed)
>
> /**
> + * kvm_supports_mpstate:
> + *
> + * Returns: true if the kvm side supports MP states which is
> + * required to indicate to kvm that a vcpu is currently halted"...and make KVM wait for resumption inside the kernel instead for reporting halt to userspace." Or so. That's why I asked for calling this helper differently: to express the concept behind it, not the implementation detail "mpstate" (which is an x86-caused misnomer). > + */ > +#define kvm_halt_in_kernel() (kvm_halt_in_kernel_allowed) > + > +/** > * kvm_irqfds_enabled: > * > * Returns: true if we can use irqfds to inject interrupts into > @@ -101,6 +110,7 @@ extern bool kvm_gsi_routing_allowed; > #define kvm_enabled() (0) > #define kvm_irqchip_in_kernel() (false) > #define kvm_async_interrupts_enabled() (false) > +#define kvm_halt_in_kernel() (false) > #define kvm_irqfds_enabled() (false) > #define kvm_msi_via_irqfd_enabled() (false) > #define kvm_gsi_routing_allowed() (false) > diff --git a/kvm-all.c b/kvm-all.c > index 130cdbc..2e301f5 100644 > --- a/kvm-all.c > +++ b/kvm-all.c > @@ -106,6 +106,7 @@ struct KVMState > KVMState *kvm_state; > bool kvm_kernel_irqchip; > bool kvm_async_interrupts_allowed; > +bool kvm_halt_in_kernel_allowed; > bool kvm_irqfds_allowed; > bool kvm_msi_via_irqfd_allowed; > bool kvm_gsi_routing_allowed; > @@ -1219,6 +1220,7 @@ static int kvm_irqchip_create(KVMState *s) > * interrupt delivery (though the reverse is not necessarily true) > */ > kvm_async_interrupts_allowed = true; > + kvm_halt_in_kernel_allowed = true; > > kvm_init_irq_routing(s); > > The code looks good to me. Jan
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