linux-kernel - Re: [PATCH v9 13/19] KVM: selftests: TDX: Use KVM_TDX_CAPABILITIES to validate TDs' attribute configuration

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Message-ID: <4306ca85-1dcd-47c1-bb36-b76a2efe061f@linux.intel.com>
Date: Tue, 26 Aug 2025 17:22:29 +0800
From: Binbin Wu <binbin.wu@...ux.intel.com>
To: Sagi Shahar <sagis@...gle.com>
Cc: linux-kselftest@...r.kernel.org, Paolo Bonzini <pbonzini@...hat.com>,
 Shuah Khan <shuah@...nel.org>, Sean Christopherson <seanjc@...gle.com>,
 Ackerley Tng <ackerleytng@...gle.com>, Ryan Afranji <afranji@...gle.com>,
 Andrew Jones <ajones@...tanamicro.com>,
 Isaku Yamahata <isaku.yamahata@...el.com>,
 Erdem Aktas <erdemaktas@...gle.com>,
 Rick Edgecombe <rick.p.edgecombe@...el.com>,
 Roger Wang <runanwang@...gle.com>, Oliver Upton <oliver.upton@...ux.dev>,
 "Pratik R. Sampat" <pratikrajesh.sampat@....com>,
 Reinette Chatre <reinette.chatre@...el.com>, Ira Weiny
 <ira.weiny@...el.com>, Chao Gao <chao.gao@...el.com>,
 Chenyi Qiang <chenyi.qiang@...el.com>, linux-kernel@...r.kernel.org,
 kvm@...r.kernel.org
Subject: Re: [PATCH v9 13/19] KVM: selftests: TDX: Use KVM_TDX_CAPABILITIES to
 validate TDs' attribute configuration

On 8/21/2025 12:29 PM, Sagi Shahar wrote:
> From: Isaku Yamahata <isaku.yamahata@...el.com>
>
> This also exercises the KVM_TDX_CAPABILITIES ioctl.

That commit message should describe what the patch does instead of relying on
the title/short log.

>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@...el.com>
> Co-developed-by: Sagi Shahar <sagis@...gle.com>
> Signed-off-by: Sagi Shahar <sagis@...gle.com>
> ---
>   .../selftests/kvm/lib/x86/tdx/tdx_util.c        | 17 +++++++++++++++++
>   1 file changed, 17 insertions(+)
>
> diff --git a/tools/testing/selftests/kvm/lib/x86/tdx/tdx_util.c b/tools/testing/selftests/kvm/lib/x86/tdx/tdx_util.c
> index 3869756a5641..d8eab99d9333 100644
> --- a/tools/testing/selftests/kvm/lib/x86/tdx/tdx_util.c
> +++ b/tools/testing/selftests/kvm/lib/x86/tdx/tdx_util.c
> @@ -232,6 +232,21 @@ static void vm_tdx_filter_cpuid(struct kvm_vm *vm,
>   	free(tdx_cap);
>   }
>   
> +static void tdx_check_attributes(struct kvm_vm *vm, uint64_t attributes)
> +{
> +	struct kvm_tdx_capabilities *tdx_cap;
> +
> +	tdx_cap = tdx_read_capabilities(vm);
> +
> +	/* TDX spec: any bits 0 in supported_attrs must be 0 in attributes */
> +	TEST_ASSERT_EQ(attributes & ~tdx_cap->supported_attrs, 0);
> +
> +	/* TDX spec: any bits 1 in attributes must be 1 in supported_attrs */

The comments are not accurate.

The descriptions in TDX spec are for ATTRIBUTES_ FIXED0 and ATTRIBUTES_ FIXED1.
They are related to tdx_cap->supported_attrs returned by KVM, but they are not
the same.

> +	TEST_ASSERT_EQ(attributes & tdx_cap->supported_attrs, attributes);
> +
> +	free(tdx_cap);
> +}
> +
>   void vm_tdx_init_vm(struct kvm_vm *vm, uint64_t attributes)
>   {
>   	struct kvm_tdx_init_vm *init_vm;
> @@ -251,6 +266,8 @@ void vm_tdx_init_vm(struct kvm_vm *vm, uint64_t attributes)
>   	memcpy(&init_vm->cpuid, cpuid, kvm_cpuid2_size(cpuid->nent));
>   	free(cpuid);
>   
> +	tdx_check_attributes(vm, attributes);
> +
>   	init_vm->attributes = attributes;
>   
>   	vm_tdx_vm_ioctl(vm, KVM_TDX_INIT_VM, 0, init_vm);