Re: KVM: MMU: handle invalid root_hpa at __direct_map

[Paolo Bonzini <pbonzini@redhat.com>]

Il 19/12/2013 18:28, Marcelo Tosatti ha scritto:
> 
> It is possible for __direct_map to be called on invalid root_hpa
> (-1), two examples:
> 
> 1) try_async_pf -> can_do_async_pf
>     -> vmx_interrupt_allowed -> nested_vmx_vmexit
> 2) vmx_handle_exit -> vmx_interrupt_allowed -> nested_vmx_vmexit
> 
> Then to load_vmcs12_host_state and kvm_mmu_reset_context.
> 
> Check for this possibility, let fault exception be regenerated.
> 
> BZ: https://bugzilla.redhat.com/show_bug.cgi?id=924916
> 
> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
> 
> 
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index 40772ef..31a5702 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -2659,6 +2659,9 @@ static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
>  	int emulate = 0;
>  	gfn_t pseudo_gfn;
>  
> +	if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
> +		return 0;
> +
>  	for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) {
>  		if (iterator.level == level) {
>  			mmu_set_spte(vcpu, iterator.sptep, ACC_ALL,
> 

Applied to queue, thanks.

Paolo