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Re: [Qemu-devel] [PATCH 1/6] kvm: Decouple 'interrupt injection is async
From: |
Jan Kiszka |
Subject: |
Re: [Qemu-devel] [PATCH 1/6] kvm: Decouple 'interrupt injection is async' from 'kernel irqchip' |
Date: |
Wed, 25 Jul 2012 17:41:09 +0200 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 |
On 2012-07-25 15:24, Peter Maydell wrote:
> On x86 interrupt injection is asynchronous (and therefore
> VCPU idle management is done in the kernel) if and only
> if there is an in-kernel irqchip. On other architectures this
> isn't necessarily true (they may always do asynchronous
> injection), so define a new kvm_async_interrupt_injection()
> function instead of misusing kvm_irqchip_in_kernel().
>
> Signed-off-by: Peter Maydell <address@hidden>
> ---
> cpus.c | 3 ++-
> kvm-all.c | 7 ++++++-
> kvm-stub.c | 1 +
> kvm.h | 11 +++++++++++
> 4 files changed, 20 insertions(+), 2 deletions(-)
>
> diff --git a/cpus.c b/cpus.c
> index 756e624..584b298 100644
> --- a/cpus.c
> +++ b/cpus.c
> @@ -69,7 +69,8 @@ static bool cpu_thread_is_idle(CPUArchState *env)
> if (env->stopped || !runstate_is_running()) {
> return true;
> }
> - if (!env->halted || qemu_cpu_has_work(env) || kvm_irqchip_in_kernel()) {
> + if (!env->halted || qemu_cpu_has_work(env) ||
> + kvm_async_interrupt_injection()) {
> return false;
> }
> return true;
> diff --git a/kvm-all.c b/kvm-all.c
> index 2148b20..3354c6f 100644
> --- a/kvm-all.c
> +++ b/kvm-all.c
> @@ -100,6 +100,7 @@ struct KVMState
>
> KVMState *kvm_state;
> bool kvm_kernel_irqchip;
> +bool kvm_async_interrupt_injection;
>
> static const KVMCapabilityInfo kvm_required_capabilites[] = {
> KVM_CAP_INFO(USER_MEMORY),
> @@ -857,7 +858,7 @@ int kvm_irqchip_set_irq(KVMState *s, int irq, int level)
> struct kvm_irq_level event;
> int ret;
>
> - assert(kvm_irqchip_in_kernel());
> + assert(kvm_async_interrupt_injection());
>
> event.level = level;
> event.irq = irq;
> @@ -1201,6 +1202,10 @@ static int kvm_irqchip_create(KVMState *s)
> s->irqchip_inject_ioctl = KVM_IRQ_LINE_STATUS;
> }
> kvm_kernel_irqchip = true;
> + /* If we have an in-kernel IRQ chip then we must have asynchronous
> + * interrupt injection (though the reverse is not necessarily true)
> + */
> + kvm_async_interrupt_injection = true;
>
> kvm_init_irq_routing(s);
>
> diff --git a/kvm-stub.c b/kvm-stub.c
> index d23b11c..b4023d1 100644
> --- a/kvm-stub.c
> +++ b/kvm-stub.c
> @@ -19,6 +19,7 @@
>
> KVMState *kvm_state;
> bool kvm_kernel_irqchip;
> +bool kvm_async_interrupt_injection;
>
> int kvm_init_vcpu(CPUArchState *env)
> {
> diff --git a/kvm.h b/kvm.h
> index 2617dd5..00abe36 100644
> --- a/kvm.h
> +++ b/kvm.h
> @@ -24,13 +24,24 @@
>
> extern int kvm_allowed;
> extern bool kvm_kernel_irqchip;
> +extern bool kvm_async_interrupt_injection;
>
> #if defined CONFIG_KVM || !defined NEED_CPU_H
> #define kvm_enabled() (kvm_allowed)
> #define kvm_irqchip_in_kernel() (kvm_kernel_irqchip)
> +/**
> + * kvm_async_interrupt_injection:
> + *
> + * Returns: true if we can inject interrupts into a KVM CPU
> + * asynchronously (ie by ioctl from any thread at any time)
> + * rather than having to do interrupt delivery synchronously
> + * (where the vcpu must be stopped at a suitable point first).
> + */
> +#define kvm_async_interrupt_injection() (kvm_async_interrupt_injection)
> #else
> #define kvm_enabled() (0)
> #define kvm_irqchip_in_kernel() (false)
> +#define kvm_async_interrupt_injection() (false)
> #endif
>
> struct kvm_run;
>
Acked-by: Jan Kiszka <address@hidden>
--
Siemens AG, Corporate Technology, CT RTC ITP SDP-DE
Corporate Competence Center Embedded Linux