Re: [PATCH 2/2] make the injection of interrupts run at sleepable mode.

Avi Kivity
2007-10-16T09:41:56Z

Izik Eidus wrote:

> diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
> index 74b427f..0b12a98 100644
> --- a/drivers/kvm/kvm.h
> +++ b/drivers/kvm/kvm.h
> @@ -68,6 +68,7 @@
> * vcpu->requests bit members
> */
> #define KVM_TLB_FLUSH 0
> +#define VMX_INJECT_RMODE_IRQ 1
>
> /*
> * Address types:
> @@ -319,6 +320,7 @@ struct kvm_vcpu {
> int guest_mode;
> unsigned long requests;
> unsigned long irq_summary; /* bit vector: 1 per word in irq_pending */
> + int inject_rmode_irq;
> DECLARE_BITMAP(irq_pending, KVM_NR_INTERRUPTS);
> unsigned long regs[NR_VCPU_REGS]; /* for rsp: vcpu_load_rsp_rip() */
> unsigned long rip; /* needs vcpu_load_rsp_rip() */
> @@ -520,6 +522,7 @@ struct kvm_x86_ops {
> void (*inject_pending_irq)(struct kvm_vcpu *vcpu);
> void (*inject_pending_vectors)(struct kvm_vcpu *vcpu,
> struct kvm_run *run);
> + void (*vmx_inject_rmode_irq)(struct kvm_vcpu *vcpu, int irq);
> };
>
> extern struct kvm_x86_ops *kvm_x86_ops;
> diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
> index f58d49b..0e2bbe5 100644
> --- a/drivers/kvm/kvm_main.c
> +++ b/drivers/kvm/kvm_main.c
> @@ -2178,6 +2178,10 @@ again:
> if (unlikely(r))
> goto out;
>
> +vmx_inject_rmode:
> + if (test_and_clear_bit(VMX_INJECT_RMODE_IRQ, &vcpu->requests))
> + kvm_x86_ops->vmx_inject_rmode_irq(vcpu, vcpu->inject_rmode_irq);
> +
> preempt_disable();
>
> kvm_x86_ops->prepare_guest_switch(vcpu);
> @@ -2194,10 +2198,22 @@ again:
> goto out;
> }
>
> - if (irqchip_in_kernel(vcpu->kvm))
> + if (irqchip_in_kernel(vcpu->kvm)) {
> kvm_x86_ops->inject_pending_irq(vcpu);
> - else if (!vcpu->mmio_read_completed)
> + if (test_bit(VMX_INJECT_RMODE_IRQ, &vcpu->requests)) {
> + local_irq_enable();
> + preempt_enable();
> + goto vmx_inject_rmode;
> + }
> + }
> + else if (!vcpu->mmio_read_completed) {
> kvm_x86_ops->inject_pending_vectors(vcpu, kvm_run);
> + if (test_bit(VMX_INJECT_RMODE_IRQ, &vcpu->requests)) {
> + local_irq_enable();
> + preempt_enable();
> + goto vmx_inject_rmode;
> + }
> + }
>
>

This exposes a minor implementation details (how real mode irqs are
injected on intel) to the core code. How about we move all interrupt
injection out of the critical section? That will improve latency as well.

--
error compiling committee.c: too many arguments to function