Re: [PATCH v18 020/121] x86/virt/tdx: Get system-wide info about TDX module on initialization

[Yuan Yao]

On Mon, Jan 22, 2024 at 03:52:56PM -0800, isaku.yamahata@xxxxxxxxx wrote:
> From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
>
> TDX KVM needs system-wide information about the TDX module, store it in
> struct tdx_info.
>
> TODO: Once TDX host patch series introduces a framework to read TDX meta
> data, convert the code to it.
>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
> ---
> Change v18:
> - Newly Added
> ---
>  arch/x86/include/uapi/asm/kvm.h | 11 +++++
>  arch/x86/kvm/vmx/main.c         |  9 +++-
>  arch/x86/kvm/vmx/tdx.c          | 79 ++++++++++++++++++++++++++++++++-
>  arch/x86/kvm/vmx/x86_ops.h      |  2 +
>  4 files changed, 99 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
> index aa7a56a47564..45b2c2304491 100644
> --- a/arch/x86/include/uapi/asm/kvm.h
> +++ b/arch/x86/include/uapi/asm/kvm.h
> @@ -567,4 +567,15 @@ struct kvm_pmu_event_filter {
>  #define KVM_X86_TDX_VM		2
>  #define KVM_X86_SNP_VM		3
>
> +#define KVM_TDX_CPUID_NO_SUBLEAF	((__u32)-1)
> +
> +struct kvm_tdx_cpuid_config {
> +	__u32 leaf;
> +	__u32 sub_leaf;
> +	__u32 eax;
> +	__u32 ebx;
> +	__u32 ecx;
> +	__u32 edx;
> +};
> +
>  #endif /* _ASM_X86_KVM_H */
> diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
> index 62236bde3779..f181620b2922 100644
> --- a/arch/x86/kvm/vmx/main.c
> +++ b/arch/x86/kvm/vmx/main.c
> @@ -47,6 +47,13 @@ static __init int vt_hardware_setup(void)
>  	return 0;
>  }
>
> +static void vt_hardware_unsetup(void)
> +{
> +	if (enable_tdx)
> +		tdx_hardware_unsetup();
> +	vmx_hardware_unsetup();
> +}
> +
>  static int vt_vm_init(struct kvm *kvm)
>  {
>  	if (is_td(kvm))
> @@ -69,7 +76,7 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
>
>  	.check_processor_compatibility = vmx_check_processor_compat,
>
> -	.hardware_unsetup = vmx_hardware_unsetup,
> +	.hardware_unsetup = vt_hardware_unsetup,
>
>  	.hardware_enable = vt_hardware_enable,
>  	.hardware_disable = vmx_hardware_disable,
> diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
> index 1608bdf2381d..55399136b680 100644
> --- a/arch/x86/kvm/vmx/tdx.c
> +++ b/arch/x86/kvm/vmx/tdx.c
> @@ -67,7 +67,7 @@ static size_t tdx_md_element_size(u64 fid)
>  	}
>  }
>
> -int tdx_md_read(struct tdx_md_map *maps, int nr_maps)
> +static int tdx_md_read(struct tdx_md_map *maps, int nr_maps)
>  {
>  	struct tdx_md_map *m;
>  	int ret, i;
> @@ -85,9 +85,39 @@ int tdx_md_read(struct tdx_md_map *maps, int nr_maps)
>  	return 0;
>  }
>
> +struct tdx_info {
> +	u64 attributes_fixed0;
> +	u64 attributes_fixed1;
> +	u64 xfam_fixed0;
> +	u64 xfam_fixed1;
> +
> +	u16 num_cpuid_config;
> +	/* This must the last member. */
> +	DECLARE_FLEX_ARRAY(struct kvm_tdx_cpuid_config, cpuid_configs);
> +};
> +
> +/* Info about the TDX module. */
> +static struct tdx_info *tdx_info;
> +
>  static int __init tdx_module_setup(void)
>  {
> +	u16 num_cpuid_config;
>  	int ret;
> +	u32 i;
> +
> +	struct tdx_md_map mds[] = {
> +		TDX_MD_MAP(NUM_CPUID_CONFIG, &num_cpuid_config),
> +	};
> +
> +#define TDX_INFO_MAP(_field_id, _member)			\
> +	TD_SYSINFO_MAP(_field_id, struct tdx_info, _member)
> +
> +	struct tdx_metadata_field_mapping tdx_info_md[] = {
> +		TDX_INFO_MAP(ATTRS_FIXED0, attributes_fixed0),
> +		TDX_INFO_MAP(ATTRS_FIXED1, attributes_fixed1),
> +		TDX_INFO_MAP(XFAM_FIXED0, xfam_fixed0),
> +		TDX_INFO_MAP(XFAM_FIXED1, xfam_fixed1),
> +	};
>
>  	ret = tdx_enable();
>  	if (ret) {
> @@ -95,7 +125,49 @@ static int __init tdx_module_setup(void)
>  		return ret;
>  	}
>
> +	ret = tdx_md_read(mds, ARRAY_SIZE(mds));
> +	if (ret)
> +		return ret;
> +
> +	tdx_info = kzalloc(sizeof(*tdx_info) +
> +			   sizeof(*tdx_info->cpuid_configs) * num_cpuid_config,
> +			   GFP_KERNEL);
> +	if (!tdx_info)
> +		return -ENOMEM;
> +	tdx_info->num_cpuid_config = num_cpuid_config;
> +
> +	ret = tdx_sys_metadata_read(tdx_info_md, ARRAY_SIZE(tdx_info_md), tdx_info);
> +	if (ret)
> +		return ret;

"goto error_sys_rd" as below to free the tdx_info ?

> +
> +	for (i = 0; i < num_cpuid_config; i++) {
> +		struct kvm_tdx_cpuid_config *c = &tdx_info->cpuid_configs[i];
> +		u64 leaf, eax_ebx, ecx_edx;
> +		struct tdx_md_map cpuids[] = {
> +			TDX_MD_MAP(CPUID_CONFIG_LEAVES + i, &leaf),
> +			TDX_MD_MAP(CPUID_CONFIG_VALUES + i * 2, &eax_ebx),
> +			TDX_MD_MAP(CPUID_CONFIG_VALUES + i * 2 + 1, &ecx_edx),
> +		};
> +
> +		ret = tdx_md_read(cpuids, ARRAY_SIZE(cpuids));
> +		if (ret)
> +			goto error_sys_rd;
> +
> +		c->leaf = (u32)leaf;
> +		c->sub_leaf = leaf >> 32;
> +		c->eax = (u32)eax_ebx;
> +		c->ebx = eax_ebx >> 32;
> +		c->ecx = (u32)ecx_edx;
> +		c->edx = ecx_edx >> 32;
> +	}
> +
>  	return 0;
> +
> +error_sys_rd:
> +	ret = -EIO;
> +	/* kfree() accepts NULL. */
> +	kfree(tdx_info);
> +	return ret;
>  }
>
>  bool tdx_is_vm_type_supported(unsigned long type)
> @@ -163,3 +235,8 @@ int __init tdx_hardware_setup(struct kvm_x86_ops *x86_ops)
>  out:
>  	return r;
>  }
> +
> +void tdx_hardware_unsetup(void)
> +{
> +	kfree(tdx_info);
> +}
> diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h
> index 5da7a5fd91cb..9523087ae355 100644
> --- a/arch/x86/kvm/vmx/x86_ops.h
> +++ b/arch/x86/kvm/vmx/x86_ops.h
> @@ -136,9 +136,11 @@ void vmx_setup_mce(struct kvm_vcpu *vcpu);
>
>  #ifdef CONFIG_INTEL_TDX_HOST
>  int __init tdx_hardware_setup(struct kvm_x86_ops *x86_ops);
> +void tdx_hardware_unsetup(void);
>  bool tdx_is_vm_type_supported(unsigned long type);
>  #else
>  static inline int tdx_hardware_setup(struct kvm_x86_ops *x86_ops) { return -EOPNOTSUPP; }
> +static inline void tdx_hardware_unsetup(void) {}
>  static inline bool tdx_is_vm_type_supported(unsigned long type) { return false; }
>  #endif
>
> --
> 2.25.1
>
>