Re: [PATCH v6 9/9] KVM: selftests: Add a basic SEV-SNP smoke test

[Sean Christopherson <seanjc@google.com>]

On Fri, Feb 14, 2025, Pratik Rajesh Sampat wrote:
> 
> 
> On 2/11/25 8:31 PM, Sean Christopherson wrote:
> > On Mon, Feb 03, 2025, Pratik R. Sampat wrote:
> >> @@ -217,5 +244,20 @@ int main(int argc, char *argv[])
> >>  		}
> >>  	}
> >>  
> >> +	if (kvm_cpu_has(X86_FEATURE_SEV_SNP)) {
> >> +		uint64_t snp_policy = snp_default_policy();
> >> +
> >> +		test_snp(snp_policy);
> >> +		/* Test minimum firmware level */
> >> +		test_snp(snp_policy | SNP_FW_VER_MAJOR(SNP_MIN_API_MAJOR) |
> >> +			SNP_FW_VER_MINOR(SNP_MIN_API_MINOR));
> > 
> > Ah, this is where the firmware policy stuff is used.  Refresh me, can userspace
> > request _any_ major/minor as the min, and expect failure if the version isn't
> > supported?  If so, the test should iterate over the major/minor combinations that
> > are guaranteed to fail.  And if userspace can query the supported minor/major,
> > the test should iterate over all the happy versions too. 
> > 
> 
> Yes, any policy greater than the min policy (defined in sev-dev.c)
> should be supported. The sad path tests were intended to be added in the
> upcoming negative test patch series so that we could have the proper
> infrastructure to handle and report failures.
> 
> > Unless there's nothing interesting to test, I would move the major/minor stuff to
> > a separate patch.
> 
> Would you rather prefer I do the happy tests here (something like -
> min_policy and min_policy + 1?) and defer the failure tests for the
> next patchset? Or, I can remove policy testing from here entirely and
> introduce it only when the sad path testing infrastructure is ready, so
> that we can test this completely at once?

Let's do the latter.  For the initial series, do the bare minimum so that we can
get that merged, and then focus on the min API version stuff in a separate series.
The version testing shouldn't be terribly complex, but it doesn't seem like it's
entirely trivial either, and I don't want it to block the base SNP support.