Re: [PATCH][RFC] kvm-scheduler integration

[Shaohua Li <shaohua.li@intel.com>]

On Sun, 2007-07-08 at 20:58 +0800, Avi Kivity wrote:
> The only fly in the ointment is that it crashes quite soon.  Haven't
> figured
> out why yet, but comments on the general direction would be welcome.
Attached patch seems help in my test. prepare_task_switch is called with
irq disabled.


> -static void vmx_vcpu_load(struct kvm_vcpu *vcpu)
> +static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
>  {
>         u64 phys_addr = __pa(vcpu->vmcs);
> -       int cpu;
>         u64 tsc_this, delta;
> 
> -       cpu = get_cpu();
> -
> +       WARN_ON(!preempt_count());
This and below change will break preempt disabled case. better remove
them.

>         if (vcpu->cpu != cpu)
>                 vcpu_clear(vcpu);
> 
> @@ -426,9 +432,9 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu)
> 
>  static void vmx_vcpu_put(struct kvm_vcpu *vcpu)
>  {
> +       WARN_ON(!preempt_count());
>         vmx_load_host_state(vcpu);
>         kvm_put_guest_fpu(vcpu);
> -       put_cpu();
>  }

Index: linux-2.6/drivers/kvm/vmx.c
===================================================================
--- linux-2.6.orig/drivers/kvm/vmx.c
+++ linux-2.6/drivers/kvm/vmx.c
@@ -347,6 +347,7 @@ static void vmx_save_host_state(struct k
 static void vmx_load_host_state(struct kvm_vcpu *vcpu)
 {
 	struct vmx_host_state *hs = &vcpu->vmx_host_state;
+	unsigned long flags;
 
 	if (!hs->loaded)
 		return;
@@ -359,12 +360,12 @@ static void vmx_load_host_state(struct k
 		 * If we have to reload gs, we must take care to
 		 * preserve our gs base.
 		 */
-		local_irq_disable();
+		local_irq_save(flags);
 		load_gs(hs->gs_sel);
 #ifdef CONFIG_X86_64
 		wrmsrl(MSR_GS_BASE, vmcs_readl(HOST_GS_BASE));
 #endif
-		local_irq_enable();
+		local_irq_restore(flags);
 
 		reload_tss();
 	}