Re: [PATCH 1/2] VMX: Properly return error to userspace on vmentry failure

[Avi Kivity <avi@redhat.com>]

On 05/24/2010 01:01 AM, Mohammed Gamal wrote:
> The vmexit handler returns KVM_EXIT_UNKNOWN since there is no handler
> for vmentry failures. This intercepts vmentry failures and returns
> KVM_FAIL_ENTRY to userspace instead.
>
> Signed-off-by: Mohammed Gamal<m.gamal005@gmail.com>
> ---
>   arch/x86/kvm/vmx.c |    7 +++++++
>   1 files changed, 7 insertions(+), 0 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 99ae513..4edcffb 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -3665,6 +3665,13 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu)
>   	if (enable_ept&&  is_paging(vcpu))
>   		vcpu->arch.cr3 = vmcs_readl(GUEST_CR3);
>
> +	if (exit_reason&  VMX_EXIT_REASONS_FAILED_VMENTRY) {
> +		vcpu->run->exit_reason = KVM_EXIT_FAIL_ENTRY;
> +		vcpu->run->fail_entry.hardware_entry_failure_reason
> +			= exit_reason&  ~VMX_EXIT_REASONS_FAILED_VMENTRY;
> +		return 0;
> +	}
> +
>   	if (unlikely(vmx->fail)) {
>   		vcpu->run->exit_reason = KVM_EXIT_FAIL_ENTRY;
>   		vcpu->run->fail_entry.hardware_entry_failure_reason
>    

How does the user distinguish between KVM_EXIT_FAIL_ENTRY due to an exit 
reason with bit 31 set and vmlauch/vmresume failure (vmx->fail set)?  We 
need separate exit codes (with documentation in api.txt).

-- 
error compiling committee.c: too many arguments to function