Re: [PATCH 10/11] VMX: work around lacking VNMI support

[Gleb Natapov <gleb@qumranet.com>]

On Wed, Sep 24, 2008 at 04:02:36PM +0300, Gleb Natapov wrote:
> On Wed, Sep 24, 2008 at 02:56:40PM +0200, Jan Kiszka wrote:
> > > We should do something like this:
> > > 
> > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> > > index 046a91b..860e66d 100644
> > > --- a/arch/x86/kvm/vmx.c
> > > +++ b/arch/x86/kvm/vmx.c
> > > @@ -2826,10 +2826,20 @@ static int handle_task_switch(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
> > >  	unsigned long exit_qualification;
> > >  	u16 tss_selector;
> > >  	int reason;
> > > +	struct vcpu_vmx *vmx = to_vmx(vcpu);
> > >  
> > >  	exit_qualification = vmcs_readl(EXIT_QUALIFICATION);
> > >  
> > >  	reason = (u32)exit_qualification >> 30;
> > > +
> > > +	if (reason == TASK_SWITCH_GATE && vmx->vcpu.arch.nmi_injected &&
> > > +		(vmx->idt_vectoring_info & VECTORING_INFO_VALID_MASK) &&
> > > +		(vmx->idt_vectoring_info & VECTORING_INFO_TYPE_MASK) == INTR_TYPE_NMI_INTR) {
> > > +		vcpu->arch.nmi_injected = false;
> > > +		vmcs_set_bits(GUEST_INTERRUPTIBILITY_INFO,
> > > +				      GUEST_INTR_STATE_NMI);
> > > +		printk(KERN_DEBUG"NMI cause task switch. No need to reinject\n");
> > > +	}
> > 
> > OK, I just think we are not supposed to set GUEST_INTR_STATE_NMI without
> > cpu_has_virtual_nmis(). Otherwise looks reasonable. Have you tested
> > this? Does it make your 2003 power-off?
> > 
> It does power-off, but hands during reboot. Looking at it right now.
> 
OK. The hand is a bug in qemu. Apic reset function marks CPU 1 as halted
and the CPU is never enters kernel again.

--
			Gleb.