Re: [kvm-unit-tests PATCH] x86: svm: Skip NPT-only part of guest CR3 tests when NPT is disabled

[Sean Christopherson <seanjc@google.com>]

On Wed, Apr 21, 2021, Sean Christopherson wrote:
> Skip the sub-tests for guest CR3 that rely on NPT, unsurprisingly they
> fail when running with NPT disabled.  Alternatively, the test could be
> modified to poke into the legacy page tables, but obviously no one
> actually cares that much about shadow paging.
> 
> Fixes: 6d0ecbf ("nSVM: Test non-MBZ reserved bits in CR3 in long mode and legacy PAE mode")
> Signed-off-by: Sean Christopherson <seanjc@google.com>

Ping!  Doesn't look like this ever got merged.

> ---
>  x86/svm_tests.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/x86/svm_tests.c b/x86/svm_tests.c
> index 29a0b59..353ab6b 100644
> --- a/x86/svm_tests.c
> +++ b/x86/svm_tests.c
> @@ -2237,6 +2237,9 @@ static void test_cr3(void)
>  
>  	vmcb->save.cr4 = cr4_saved & ~X86_CR4_PCIDE;
>  
> +	if (!npt_supported())
> +		goto skip_npt_only;
> +
>  	/* Clear P (Present) bit in NPT in order to trigger #NPF */
>  	pdpe[0] &= ~1ULL;
>  
> @@ -2255,6 +2258,8 @@ static void test_cr3(void)
>  	    SVM_CR3_PAE_LEGACY_RESERVED_MASK, SVM_EXIT_NPF, "(PAE) ");
>  
>  	pdpe[0] |= 1ULL;
> +
> +skip_npt_only:
>  	vmcb->save.cr3 = cr3_saved;
>  	vmcb->save.cr4 = cr4_saved;
>  }
> -- 
> 2.31.1.498.g6c1eba8ee3d-goog
>