On 20/08/2015 21:38, Eugene Korenevsky wrote:
> VMWRITE instruction is not valid in compatibility mode. This is
> checked by nested_vmx_check_permission() function which throws #UD if CS.L=0.
> The additional check in is_64_bit_mode() for CS.L=0 is useless.
This is true, and it matches what handle_vmread does, on the other hand
is_long_mode is generally used to test page table type.
I think it's clearer if you change handle_vmread to use is_64_bit_mode
instead.
Paolo
> We should check only EFER.LMA=1 which is done by is_long_mode().
>
> Signed-off-by: Eugene Korenevsky <ekorenevsky@xxxxxxxxx>
> ---
> arch/x86/kvm/vmx.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index f39e24f..12bdaae 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -7034,7 +7034,7 @@ static int handle_vmwrite(struct kvm_vcpu *vcpu)
> field_value = kvm_register_readl(vcpu,
> (((vmx_instruction_info) >> 3) & 0xf));
> else {
> - mem_op_size = is_64_bit_mode(vcpu) ? 8 : 4;
> + mem_op_size = is_long_mode(vcpu) ? 8 : 4;
> if (get_vmx_mem_address(vcpu, exit_qualification,
> vmx_instruction_info, false, mem_op_size, &gva))
> return 1;
> -- 2.1.4
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