Re: [PATCH kvm-unit-tests] vmx: fixes for MAXPHYADDR requirement

["Radim Krčmář" <rkrcmar@redhat.com>]

2018-01-17 19:03+0100, Paolo Bonzini:
> The EPT access tests require at least 41 bits of guest physical address
> space.  This is because the test data needs a separate PML4 entry in the
> EPT table.  However, many consumer-grade processors have only 36 or
> 39-bit MAXPHYADDR, and the tests fail there with a page fault due to
> reserved bits set in the guest (GVA->GPA) page tables.
> 
> Add a test on MAXPHYADDR and skip the tests if they cannot run on the
> system under test, and only require 40 bits to lower the requirements.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  x86/vmx_tests.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/x86/vmx_tests.c b/x86/vmx_tests.c
> index e8c97f2..0c3b5a7 100644
> --- a/x86/vmx_tests.c
> +++ b/x86/vmx_tests.c
> @@ -2609,6 +2609,10 @@ static void ept_access_test_setup(void)
>  	if (setup_ept(false))
>  		test_skip("EPT not supported");
>  
> +	/* We use data->gpa = 1 << 39 so that test data has a separate pml4 entry */
> +	if (cpuid_maxphyaddr() < 40)

This does not help at the moment -- QEMU reports 40 even on hosts that
don't have as much.  It is a QEMU bug, so applied still, thanks.