linux-kernel - Re: [RFC 1/5] selftests: KVM: Add a basic SNP smoke test

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Message-ID: <b41f3149-1020-4996-911f-7f357db81376@amd.com>
Date: Thu, 11 Jul 2024 11:23:32 -0500
From: "Sampat, Pratik Rajesh" <pratikrajesh.sampat@....com>
To: Tom Lendacky <thomas.lendacky@....com>, <kvm@...r.kernel.org>
CC: <shuah@...nel.org>, <michael.roth@....com>, <seanjc@...gle.com>,
	<pbonzini@...hat.com>, <pgonda@...gle.com>,
	<linux-kselftest@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [RFC 1/5] selftests: KVM: Add a basic SNP smoke test

Hi Tom,

On 7/11/2024 10:56 AM, Tom Lendacky wrote:
> On 7/10/24 17:05, Pratik R. Sampat wrote:
>> Extend sev_smoke_test to also run a minimal SEV-SNP smoke test that
>> initializes and sets up private memory regions required to run a simple
>> SEV-SNP guest.
>>
>> Similar to it's SEV-ES smoke test counterpart, this also does not support
>> GHCB and ucall yet and uses the GHCB MSR protocol to trigger an exit of
>> the type KVM_EXIT_SYSTEM_EVENT.
>>
>> Also, decouple policy and type and require functions to provide both
>> such that there is no assumption regarding the type using policy.
>>
>> Signed-off-by: Pratik R. Sampat <pratikrajesh.sampat@....com>
>> ---
>>  .../selftests/kvm/include/x86_64/processor.h  |  1 +
>>  .../selftests/kvm/include/x86_64/sev.h        | 29 ++++++++
>>  tools/testing/selftests/kvm/lib/kvm_util.c    |  7 +-
>>  .../selftests/kvm/lib/x86_64/processor.c      |  6 +-
>>  tools/testing/selftests/kvm/lib/x86_64/sev.c  | 70 ++++++++++++++++++-
>>  .../selftests/kvm/x86_64/sev_smoke_test.c     | 51 ++++++++++----
>>  6 files changed, 146 insertions(+), 18 deletions(-)
>>
>> diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
>> index 8eb57de0b587..5683fc9794e4 100644
>> --- a/tools/testing/selftests/kvm/include/x86_64/processor.h
>> +++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
> 
>> +
>> +	if (kvm_cpu_has(X86_FEATURE_SNP) && is_kvm_snp_supported()) {
>> +		test_sev(guest_snp_code, KVM_X86_SNP_VM, SNP_POLICY_SMT | SNP_POLICY_RSVD_MBO);
>> +		/* Test minimum firmware level */
>> +		test_sev(guest_snp_code, KVM_X86_SNP_VM,
>> +			 SNP_POLICY_SMT | SNP_POLICY_RSVD_MBO |
>> +			 (SNP_FW_REQ_VER_MAJOR * SNP_POLICY_ABI_MAJOR) |
>> +			 (SNP_FW_REQ_VER_MINOR * SNP_POLICY_ABI_MINOR));
> 
> This seems an odd way of setting these fields. Maybe, instead, use a
> couple of macros that take the values and shift appropriately and ensure
> that they don't exceed the 8-bits each field occupies.
> 

Sure, I will clean this up and ensure the flags are set up more elegantly.

> Thanks,
> Tom
> 
>>