linux-kernel - Re: [PATCH v9 05/19] KVM: selftests: Update kvm_init_vm_address

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Message-ID: <176247c7-6801-4e06-860e-4a6b8e77ba20@linux.intel.com>
Date: Tue, 26 Aug 2025 13:51:36 +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, Adrian Hunter <adrian.hunter@...el.com>
Subject: Re: [PATCH v9 05/19] KVM: selftests: Update
 kvm_init_vm_address_properties() for TDX

On 8/21/2025 12:28 PM, Sagi Shahar wrote:
> From: Isaku Yamahata <isaku.yamahata@...el.com>
>
> Let kvm_init_vm_address_properties() initialize vm->arch.{s_bit, tag_mask}
> similar to SEV.
>
> TDX sets the shared bit based on the guest physical address width and
> currently supports 48 and 52 widths.
>
> Co-developed-by: Adrian Hunter <adrian.hunter@...el.com>
> Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
> 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/include/x86/tdx/tdx_util.h       | 14 ++++++++++++++
>   tools/testing/selftests/kvm/lib/x86/processor.c    | 12 ++++++++++--
>   2 files changed, 24 insertions(+), 2 deletions(-)
>   create mode 100644 tools/testing/selftests/kvm/include/x86/tdx/tdx_util.h
>
> diff --git a/tools/testing/selftests/kvm/include/x86/tdx/tdx_util.h b/tools/testing/selftests/kvm/include/x86/tdx/tdx_util.h
> new file mode 100644
> index 000000000000..286d5e3c24b1
> --- /dev/null
> +++ b/tools/testing/selftests/kvm/include/x86/tdx/tdx_util.h
> @@ -0,0 +1,14 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +#ifndef SELFTESTS_TDX_TDX_UTIL_H
> +#define SELFTESTS_TDX_TDX_UTIL_H
> +
> +#include <stdbool.h>
> +
> +#include "kvm_util.h"
> +
> +static inline bool is_tdx_vm(struct kvm_vm *vm)
> +{
> +	return vm->type == KVM_X86_TDX_VM;
> +}

If the branch "vm->type != KVM_X86_TDX_VM" in patch 04/19
is still needed, this helper could be added earlier and used instead of
open code.

> +
> +#endif // SELFTESTS_TDX_TDX_UTIL_H
> diff --git a/tools/testing/selftests/kvm/lib/x86/processor.c b/tools/testing/selftests/kvm/lib/x86/processor.c
> index 1eae92957456..6dbf40cbbc2a 100644
> --- a/tools/testing/selftests/kvm/lib/x86/processor.c
> +++ b/tools/testing/selftests/kvm/lib/x86/processor.c
> @@ -8,6 +8,7 @@
>   #include "kvm_util.h"
>   #include "processor.h"
>   #include "sev.h"
> +#include "tdx/tdx_util.h"
>   
>   #ifndef NUM_INTERRUPTS
>   #define NUM_INTERRUPTS 256
> @@ -1190,12 +1191,19 @@ void kvm_get_cpu_address_width(unsigned int *pa_bits, unsigned int *va_bits)
>   
>   void kvm_init_vm_address_properties(struct kvm_vm *vm)
>   {
> +	uint32_t gpa_bits = kvm_cpu_property(X86_PROPERTY_GUEST_MAX_PHY_ADDR);
> +
> +	vm->arch.sev_fd = -1;
> +
>   	if (is_sev_vm(vm)) {
>   		vm->arch.sev_fd = open_sev_dev_path_or_exit();
>   		vm->arch.c_bit = BIT_ULL(this_cpu_property(X86_PROPERTY_SEV_C_BIT));
>   		vm->gpa_tag_mask = vm->arch.c_bit;
> -	} else {
> -		vm->arch.sev_fd = -1;
> +	} else if (is_tdx_vm(vm)) {
> +		TEST_ASSERT(gpa_bits == 48 || gpa_bits == 52,
> +			    "TDX: bad X86_PROPERTY_GUEST_MAX_PHY_ADDR value: %u", gpa_bits);
> +		vm->arch.s_bit = 1ULL << (gpa_bits - 1);

Nit: Use BIT_ULL().

> +		vm->gpa_tag_mask = vm->arch.s_bit;
>   	}
>   }
>