Re: KVM: VMX: flush TLB with INVEPT on cpu migration

[Max Laier <max@love2party.net>]

On Friday 02 October 2009 00:16:58 you wrote:
> It is possible that stale EPTP-tagged mappings are used, if a
> vcpu migrates to a different pcpu.
> 
> Set KVM_REQ_TLB_FLUSH in vmx_vcpu_load, when switching pcpus, which
> will invalidate both VPID and EPT mappings on the next vm-entry.

Thank you - I was at the brink of a nervous break-down before discovering 
this.  Maybe it would help for the future to add a comment to 
ept_misconfig_inspect_spte that explains that this might be caused by out of 
sync tlbs, too (esp. when it doesn't show an apparent cause of the misconfig)

> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
> 
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index e86f1a6..97f4265 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -708,7 +708,7 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int
>  cpu) if (vcpu->cpu != cpu) {
>  		vcpu_clear(vmx);
>  		kvm_migrate_timers(vcpu);
> -		vpid_sync_vcpu_all(vmx);
> +		set_bit(KVM_REQ_TLB_FLUSH, &vcpu->requests);
>  		local_irq_disable();
>  		list_add(&vmx->local_vcpus_link,
>  			 &per_cpu(vcpus_on_cpu, cpu));
> --
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> 
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