Re: [PATCH v6 03/16] KVM: TDX: Pass KVM page level to tdh_mem_page_add() and tdh_mem_page_aug()

[Binbin Wu]

On 11/7/2023 11:00 PM, isaku.yamahata@xxxxxxxxx wrote:
> From: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
>
> Level info is needed in tdh_clflush_page() to generate the correct page
> size.

tdh_clflush_page() -> tdx_clflush_page()

> Besides, explicitly pass level info to SEAMCALL instead of assuming
> it's zero. It works naturally when 2MB support lands.
>
> Signed-off-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
> ---
>   arch/x86/kvm/vmx/tdx.c     |  7 ++++---
>   arch/x86/kvm/vmx/tdx_ops.h | 19 ++++++++++++-------
>   2 files changed, 16 insertions(+), 10 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
> index 8b58d91bda4e..2d5c86e06c5f 100644
> --- a/arch/x86/kvm/vmx/tdx.c
> +++ b/arch/x86/kvm/vmx/tdx.c
> @@ -1468,7 +1468,7 @@ static int tdx_sept_page_aug(struct kvm *kvm, gfn_t gfn,
>   	union tdx_sept_entry entry;
>   	u64 err;
>   
> -	err = tdh_mem_page_aug(kvm_tdx->tdr_pa, gpa, hpa, &out);
> +	err = tdh_mem_page_aug(kvm_tdx->tdr_pa, gpa, tdx_level, hpa, &out);
>   	if (unlikely(err == TDX_ERROR_SEPT_BUSY)) {
>   		tdx_unpin(kvm, pfn);
>   		return -EAGAIN;
> @@ -1497,6 +1497,7 @@ static int tdx_sept_page_aug(struct kvm *kvm, gfn_t gfn,
>   static int tdx_sept_page_add(struct kvm *kvm, gfn_t gfn,
>   			     enum pg_level level, kvm_pfn_t pfn)
>   {
> +	int tdx_level = pg_level_to_tdx_sept_level(level);
>   	struct kvm_tdx *kvm_tdx = to_kvm_tdx(kvm);
>   	hpa_t hpa = pfn_to_hpa(pfn);
>   	gpa_t gpa = gfn_to_gpa(gfn);
> @@ -1531,8 +1532,8 @@ static int tdx_sept_page_add(struct kvm *kvm, gfn_t gfn,
>   	kvm_tdx->source_pa = INVALID_PAGE;
>   
>   	do {
> -		err = tdh_mem_page_add(kvm_tdx->tdr_pa, gpa, hpa, source_pa,
> -				       &out);
> +		err = tdh_mem_page_add(kvm_tdx->tdr_pa, gpa, tdx_level, hpa,
> +				       source_pa, &out);
>   		/*
>   		 * This path is executed during populating initial guest memory
>   		 * image. i.e. before running any vcpu.  Race is rare.
> diff --git a/arch/x86/kvm/vmx/tdx_ops.h b/arch/x86/kvm/vmx/tdx_ops.h
> index e726102d3523..0f2df7198bde 100644
> --- a/arch/x86/kvm/vmx/tdx_ops.h
> +++ b/arch/x86/kvm/vmx/tdx_ops.h
> @@ -63,6 +63,11 @@ static inline u64 tdx_seamcall(u64 op, u64 rcx, u64 rdx, u64 r8, u64 r9,
>   void pr_tdx_error(u64 op, u64 error_code, const struct tdx_module_args *out);
>   #endif
>   
> +static inline enum pg_level tdx_sept_level_to_pg_level(int tdx_level)
> +{
> +	return tdx_level + 1;
> +}
> +
>   static inline void tdx_clflush_page(hpa_t addr, enum pg_level level)
>   {
>   	clflush_cache_range(__va(addr), KVM_HPAGE_SIZE(level));
> @@ -104,11 +109,11 @@ static inline u64 tdh_mng_addcx(hpa_t tdr, hpa_t addr)
>   	return tdx_seamcall(TDH_MNG_ADDCX, addr, tdr, 0, 0, NULL);
>   }
>   
> -static inline u64 tdh_mem_page_add(hpa_t tdr, gpa_t gpa, hpa_t hpa, hpa_t source,
> -				   struct tdx_module_args *out)
> +static inline u64 tdh_mem_page_add(hpa_t tdr, gpa_t gpa, int level, hpa_t hpa,
> +				   hpa_t source, struct tdx_module_args *out)
>   {
> -	tdx_clflush_page(hpa, PG_LEVEL_4K);
> -	return tdx_seamcall_sept(TDH_MEM_PAGE_ADD, gpa, tdr, hpa, source, out);
> +	tdx_clflush_page(hpa, tdx_sept_level_to_pg_level(level));
> +	return tdx_seamcall_sept(TDH_MEM_PAGE_ADD, gpa | level, tdr, hpa, source, out);
>   }

For TDH_MEM_PAGE_ADD, only 4K page is supported, is this change necessary?
Or maybe huge page can be supported by TDH_MEM_PAGE_ADD in the future?

>   
>   static inline u64 tdh_mem_sept_add(hpa_t tdr, gpa_t gpa, int level, hpa_t page,
> @@ -143,11 +148,11 @@ static inline u64 tdh_mem_page_relocate(hpa_t tdr, gpa_t gpa, hpa_t hpa,
>   	return tdx_seamcall_sept(TDH_MEM_PAGE_RELOCATE, gpa, tdr, hpa, 0, out);
>   }
>   
> -static inline u64 tdh_mem_page_aug(hpa_t tdr, gpa_t gpa, hpa_t hpa,
> +static inline u64 tdh_mem_page_aug(hpa_t tdr, gpa_t gpa, int level, hpa_t hpa,
>   				   struct tdx_module_args *out)
>   {
> -	tdx_clflush_page(hpa, PG_LEVEL_4K);
> -	return tdx_seamcall_sept(TDH_MEM_PAGE_AUG, gpa, tdr, hpa, 0, out);
> +	tdx_clflush_page(hpa, tdx_sept_level_to_pg_level(level));
> +	return tdx_seamcall_sept(TDH_MEM_PAGE_AUG, gpa | level, tdr, hpa, 0, out);
>   }
>   
>   static inline u64 tdh_mem_range_block(hpa_t tdr, gpa_t gpa, int level,