linux-kernel - Re: [PATCH v18 056/121] KVM: TDX: Add accessors VMX VMCS helpers

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Date: Mon, 5 Feb 2024 09:53:11 +0800
From: Binbin Wu <binbin.wu@...ux.intel.com>
To: isaku.yamahata@...el.com
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
 isaku.yamahata@...il.com, Paolo Bonzini <pbonzini@...hat.com>,
 erdemaktas@...gle.com, Sean Christopherson <seanjc@...gle.com>,
 Sagi Shahar <sagis@...gle.com>, Kai Huang <kai.huang@...el.com>,
 chen.bo@...el.com, hang.yuan@...el.com, tina.zhang@...el.com
Subject: Re: [PATCH v18 056/121] KVM: TDX: Add accessors VMX VMCS helpers



On 1/23/2024 7:53 AM, isaku.yamahata@...el.com wrote:
> From: Isaku Yamahata <isaku.yamahata@...el.com>
>
> TDX defines SEAMCALL APIs to access TDX control structures corresponding to
> the VMX VMCS.  Introduce helper accessors to hide its SEAMCALL ABI details.
>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@...el.com>
> ---
>   arch/x86/kvm/vmx/tdx.h | 95 ++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 95 insertions(+)
>
> diff --git a/arch/x86/kvm/vmx/tdx.h b/arch/x86/kvm/vmx/tdx.h
> index d3077151252c..c8a52eedde02 100644
> --- a/arch/x86/kvm/vmx/tdx.h
> +++ b/arch/x86/kvm/vmx/tdx.h
> @@ -58,6 +58,101 @@ static inline struct vcpu_tdx *to_tdx(struct kvm_vcpu *vcpu)
>   	return container_of(vcpu, struct vcpu_tdx, vcpu);
>   }
>   
> +static __always_inline void tdvps_vmcs_check(u32 field, u8 bits)
> +{
> +#define VMCS_ENC_ACCESS_TYPE_MASK	0x1UL
> +#define VMCS_ENC_ACCESS_TYPE_FULL	0x0UL
> +#define VMCS_ENC_ACCESS_TYPE_HIGH	0x1UL
> +#define VMCS_ENC_ACCESS_TYPE(field)	((field) & VMCS_ENC_ACCESS_TYPE_MASK)
> +
> +	/* TDX is 64bit only.  HIGH field isn't supported. */
> +	BUILD_BUG_ON_MSG(__builtin_constant_p(field) &&
> +			 VMCS_ENC_ACCESS_TYPE(field) == VMCS_ENC_ACCESS_TYPE_HIGH,
> +			 "Read/Write to TD VMCS *_HIGH fields not supported");
> +
> +	BUILD_BUG_ON(bits != 16 && bits != 32 && bits != 64);
> +
> +#define VMCS_ENC_WIDTH_MASK	GENMASK(14, 13)
> +#define VMCS_ENC_WIDTH_16BIT	(0UL << 13)
> +#define VMCS_ENC_WIDTH_64BIT	(1UL << 13)
> +#define VMCS_ENC_WIDTH_32BIT	(2UL << 13)
> +#define VMCS_ENC_WIDTH_NATURAL	(3UL << 13)
> +#define VMCS_ENC_WIDTH(field)	((field) & VMCS_ENC_WIDTH_MASK)
> +
> +	/* TDX is 64bit only.  i.e. natural width = 64bit. */
> +	BUILD_BUG_ON_MSG(bits != 64 && __builtin_constant_p(field) &&
> +			 (VMCS_ENC_WIDTH(field) == VMCS_ENC_WIDTH_64BIT ||
> +			  VMCS_ENC_WIDTH(field) == VMCS_ENC_WIDTH_NATURAL),
> +			 "Invalid TD VMCS access for 64-bit field");
> +	BUILD_BUG_ON_MSG(bits != 32 && __builtin_constant_p(field) &&
> +			 VMCS_ENC_WIDTH(field) == VMCS_ENC_WIDTH_32BIT,
> +			 "Invalid TD VMCS access for 32-bit field");
> +	BUILD_BUG_ON_MSG(bits != 16 && __builtin_constant_p(field) &&
> +			 VMCS_ENC_WIDTH(field) == VMCS_ENC_WIDTH_16BIT,
> +			 "Invalid TD VMCS access for 16-bit field");
> +}
> +
> +static __always_inline void tdvps_state_non_arch_check(u64 field, u8 bits) {}
> +static __always_inline void tdvps_management_check(u64 field, u8 bits) {}

Should this two APIs be added along with for he accessors for MANAGEMENT /
STATE_NON_ARCH?

> +
> +#define TDX_BUILD_TDVPS_ACCESSORS(bits, uclass, lclass)				\
> +static __always_inline u##bits td_##lclass##_read##bits(struct vcpu_tdx *tdx,	\
> +							u32 field)		\
> +{										\
> +	struct tdx_module_args out;						\
> +	u64 err;								\
> +										\
> +	tdvps_##lclass##_check(field, bits);					\
> +	err = tdh_vp_rd(tdx->tdvpr_pa, TDVPS_##uclass(field), &out);		\
> +	if (KVM_BUG_ON(err, tdx->vcpu.kvm)) {					\
> +		pr_err("TDH_VP_RD["#uclass".0x%x] failed: 0x%llx\n",		\
> +		       field, err);						\
> +		return 0;							\
> +	}									\
> +	return (u##bits)out.r8;							\
> +}										\
> +static __always_inline void td_##lclass##_write##bits(struct vcpu_tdx *tdx,	\
> +						      u32 field, u##bits val)	\
> +{										\
> +	struct tdx_module_args out;						\
> +	u64 err;								\
> +										\
> +	tdvps_##lclass##_check(field, bits);					\
> +	err = tdh_vp_wr(tdx->tdvpr_pa, TDVPS_##uclass(field), val,		\
> +		      GENMASK_ULL(bits - 1, 0), &out);				\
> +	if (KVM_BUG_ON(err, tdx->vcpu.kvm))					\
> +		pr_err("TDH_VP_WR["#uclass".0x%x] = 0x%llx failed: 0x%llx\n",	\
> +		       field, (u64)val, err);					\
> +}										\
> +static __always_inline void td_##lclass##_setbit##bits(struct vcpu_tdx *tdx,	\
> +						       u32 field, u64 bit)	\
> +{										\
> +	struct tdx_module_args out;						\
> +	u64 err;								\
> +										\
> +	tdvps_##lclass##_check(field, bits);					\
> +	err = tdh_vp_wr(tdx->tdvpr_pa, TDVPS_##uclass(field), bit, bit, &out);	\
> +	if (KVM_BUG_ON(err, tdx->vcpu.kvm))					\
> +		pr_err("TDH_VP_WR["#uclass".0x%x] |= 0x%llx failed: 0x%llx\n",	\
> +		       field, bit, err);					\
> +}										\
> +static __always_inline void td_##lclass##_clearbit##bits(struct vcpu_tdx *tdx,	\
> +							 u32 field, u64 bit)	\
> +{										\
> +	struct tdx_module_args out;						\
> +	u64 err;								\
> +										\
> +	tdvps_##lclass##_check(field, bits);					\
> +	err = tdh_vp_wr(tdx->tdvpr_pa, TDVPS_##uclass(field), 0, bit, &out);	\
> +	if (KVM_BUG_ON(err, tdx->vcpu.kvm))					\
> +		pr_err("TDH_VP_WR["#uclass".0x%x] &= ~0x%llx failed: 0x%llx\n",	\
> +		       field, bit,  err);					\
> +}
> +
> +TDX_BUILD_TDVPS_ACCESSORS(16, VMCS, vmcs);
> +TDX_BUILD_TDVPS_ACCESSORS(32, VMCS, vmcs);
> +TDX_BUILD_TDVPS_ACCESSORS(64, VMCS, vmcs);
> +
>   static __always_inline u64 td_tdcs_exec_read64(struct kvm_tdx *kvm_tdx, u32 field)
>   {
>   	struct tdx_module_args out;