Re: [RFC PATCH 13/13] KVM: x86: remove struct kvm_arch.tdp_max_page_level

[Xiaoyao Li]

On 8/8/2022 6:18 AM, isaku.yamahata@xxxxxxxxx wrote:
> From: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
>
> Now that everything is there to support large page for TD guest.  Remove
> tdp_max_page_level from struct kvm_arch that limits the page size.

Isaku, we cannot do this to remove tdp_max_page_level. Instead, we need 
assign it as PG_LEVEL_2M, because TDX currently only supports AUG'ing a 
4K/2M page, 1G is not supported yet.

> Signed-off-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
> ---
>   arch/x86/include/asm/kvm_host.h | 1 -
>   arch/x86/kvm/mmu/mmu.c          | 1 -
>   arch/x86/kvm/mmu/mmu_internal.h | 2 +-
>   arch/x86/kvm/vmx/tdx.c          | 3 ---
>   4 files changed, 1 insertion(+), 6 deletions(-)
>
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index a6bfcabcbbd7..80f2bc3fbf0c 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -1190,7 +1190,6 @@ struct kvm_arch {
>   	unsigned long n_requested_mmu_pages;
>   	unsigned long n_max_mmu_pages;
>   	unsigned int indirect_shadow_pages;
> -	int tdp_max_page_level;
>   	u8 mmu_valid_gen;
>   	struct hlist_head mmu_page_hash[KVM_NUM_MMU_PAGES];
>   	struct list_head active_mmu_pages;
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index ba21503fa46f..0cbd52c476d7 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -6232,7 +6232,6 @@ int kvm_mmu_init_vm(struct kvm *kvm)
>   	kvm->arch.split_desc_cache.kmem_cache = pte_list_desc_cache;
>   	kvm->arch.split_desc_cache.gfp_zero = __GFP_ZERO;
>   
> -	kvm->arch.tdp_max_page_level = KVM_MAX_HUGEPAGE_LEVEL;
>   	return 0;
>   }
>   
> diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
> index e5d5fea29bfa..82b220c4d1bd 100644
> --- a/arch/x86/kvm/mmu/mmu_internal.h
> +++ b/arch/x86/kvm/mmu/mmu_internal.h
> @@ -395,7 +395,7 @@ static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
>   			is_nx_huge_page_enabled(vcpu->kvm),
>   		.is_private = kvm_is_private_gpa(vcpu->kvm, cr2_or_gpa),
>   
> -		.max_level = vcpu->kvm->arch.tdp_max_page_level,
> +		.max_level = KVM_MAX_HUGEPAGE_LEVEL,
>   		.req_level = PG_LEVEL_4K,
>   		.goal_level = PG_LEVEL_4K,
>   	};
> diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
> index a340caeb9c62..72f21f5f78af 100644
> --- a/arch/x86/kvm/vmx/tdx.c
> +++ b/arch/x86/kvm/vmx/tdx.c
> @@ -460,9 +460,6 @@ int tdx_vm_init(struct kvm *kvm)
>   	 */
>   	kvm_mmu_set_mmio_spte_mask(kvm, 0, VMX_EPT_RWX_MASK);
>   
> -	/* TODO: Enable 2mb and 1gb large page support. */
> -	kvm->arch.tdp_max_page_level = PG_LEVEL_4K;
> -
>   	/* vCPUs can't be created until after KVM_TDX_INIT_VM. */
>   	kvm->max_vcpus = 0;
>