Re: [PATCH 1/6] KVM: nVMX: delay loading of PDPTRs to KVM_REQ_GET_NESTED_STATE_PAGES

[Paolo Bonzini <pbonzini@redhat.com>]

On 01/04/21 16:18, Maxim Levitsky wrote:
> Similar to the rest of guest page accesses after migration,
> this should be delayed to KVM_REQ_GET_NESTED_STATE_PAGES
> request.
> 
> Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
> ---
>   arch/x86/kvm/vmx/nested.c | 14 +++++++++-----
>   1 file changed, 9 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> index fd334e4aa6db..b44f1f6b68db 100644
> --- a/arch/x86/kvm/vmx/nested.c
> +++ b/arch/x86/kvm/vmx/nested.c
> @@ -2564,11 +2564,6 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
>   		return -EINVAL;
>   	}
>   
> -	/* Shadow page tables on either EPT or shadow page tables. */
> -	if (nested_vmx_load_cr3(vcpu, vmcs12->guest_cr3, nested_cpu_has_ept(vmcs12),
> -				entry_failure_code))
> -		return -EINVAL;
> -
>   	/*
>   	 * Immediately write vmcs02.GUEST_CR3.  It will be propagated to vmcs12
>   	 * on nested VM-Exit, which can occur without actually running L2 and
> @@ -3109,11 +3104,16 @@ static bool nested_get_evmcs_page(struct kvm_vcpu *vcpu)
>   static bool nested_get_vmcs12_pages(struct kvm_vcpu *vcpu)
>   {
>   	struct vmcs12 *vmcs12 = get_vmcs12(vcpu);
> +	enum vm_entry_failure_code entry_failure_code;
>   	struct vcpu_vmx *vmx = to_vmx(vcpu);
>   	struct kvm_host_map *map;
>   	struct page *page;
>   	u64 hpa;
>   
> +	if (nested_vmx_load_cr3(vcpu, vmcs12->guest_cr3, nested_cpu_has_ept(vmcs12),
> +				&entry_failure_code))
> +		return false;
> +
>   	if (nested_cpu_has2(vmcs12, SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES)) {
>   		/*
>   		 * Translate L1 physical address to host physical
> @@ -3357,6 +3357,10 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu,
>   	}
>   
>   	if (from_vmentry) {
> +		if (nested_vmx_load_cr3(vcpu, vmcs12->guest_cr3,
> +		    nested_cpu_has_ept(vmcs12), &entry_failure_code))
> +			goto vmentry_fail_vmexit_guest_mode;
> +
>   		failed_index = nested_vmx_load_msr(vcpu,
>   						   vmcs12->vm_entry_msr_load_addr,
>   						   vmcs12->vm_entry_msr_load_count);
> 

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>