Re: [kvm-unit-tests PATCH] x86: vmx_tests: pml: Skip PML test if it's not enabled in underlying

[Sean Christopherson <seanjc@google.com>]

On Sun, Jul 25, 2021, Robert Hoo wrote:
> PML in VM depends on "enable PML" in VM-execution control, check this
> before vmwrite to PMLADDR, because this field doesn't exist if PML is
> disabled in VM-execution control.

No, the field doesn't exist if the CPU doesn't support PML.  Whether or not PML
is enabled in the execution controls is irrelevant.  pml_init() checks for both
secondary execution controls and PML support (with bad indentation).

	if (!(ctrl_cpu_rev[0].clr & CPU_SECONDARY) ||
		!(ctrl_cpu_rev[1].clr & CPU_PML)) {
		printf("\tPML is not supported");
		return VMX_TEST_EXIT;
	}

	pml_log = alloc_page();
	vmcs_write(PMLADDR, (u64)pml_log);
	vmcs_write(GUEST_PML_INDEX, PML_INDEX - 1);

> Signed-off-by: Robert Hoo <robert.hu@linux.intel.com>
> ---
>  x86/vmx_tests.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/x86/vmx_tests.c b/x86/vmx_tests.c
> index 4f712eb..8663112 100644
> --- a/x86/vmx_tests.c
> +++ b/x86/vmx_tests.c
> @@ -1502,13 +1502,16 @@ static int pml_init(struct vmcs *vmcs)
>  		return VMX_TEST_EXIT;
>  	}
>  
> +	ctrl_cpu = vmcs_read(CPU_EXEC_CTRL1) & CPU_PML;
> +	if (!ctrl_cpu) {
> +		printf("\tPML is not enabled\n");
> +		return VMX_TEST_EXIT;
> +	}
> +
>  	pml_log = alloc_page();
>  	vmcs_write(PMLADDR, (u64)pml_log);
>  	vmcs_write(GUEST_PML_INDEX, PML_INDEX - 1);
>  
> -	ctrl_cpu = vmcs_read(CPU_EXEC_CTRL1) | CPU_PML;
> -	vmcs_write(CPU_EXEC_CTRL1, ctrl_cpu);
> -
>  	return VMX_TEST_START;
>  }
>  
> -- 
> 1.8.3.1
>