On Fri, 2022-03-04 at 11:48 -0800, isaku.yamahata@xxxxxxxxx wrote:
> From: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
>
> In the existing x86 KVM MMU code, there is already max_level member in
> struct kvm_page_fault with KVM_MAX_HUGEPAGE_LEVEL initial value. The KVM
> page fault handler denies page size larger than max_level.
>
> Add per-VM member to indicate the allowed maximum page size with
> KVM_MAX_HUGEPAGE_LEVEL as default value and initialize max_level in struct
> kvm_page_fault with it.
>
> For the guest TD, the set per-VM value for allows maximum page size to 4K
> page size. Then only allowed page size is 4K. It means large page is
> disabled.
Do not support large page for TD is the reason that you want this change, but
not the result. Please refine a little bit.
>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
> ---
> arch/x86/include/asm/kvm_host.h | 1 +
> arch/x86/kvm/mmu.h | 2 +-
> arch/x86/kvm/mmu/mmu.c | 2 ++
> 3 files changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index d8b78d6abc10..d33d79f2af2d 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -1053,6 +1053,7 @@ 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.h b/arch/x86/kvm/mmu.h
> index 0ae91b8b25df..650989c37f2e 100644
> --- a/arch/x86/kvm/mmu.h
> +++ b/arch/x86/kvm/mmu.h
> @@ -192,7 +192,7 @@ static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
> .is_tdp = likely(vcpu->arch.mmu->page_fault == kvm_tdp_page_fault),
> .nx_huge_page_workaround_enabled = is_nx_huge_page_enabled(),
>
> - .max_level = KVM_MAX_HUGEPAGE_LEVEL,
> + .max_level = vcpu->kvm->arch.tdp_max_page_level,
> .req_level = PG_LEVEL_4K,
> .goal_level = PG_LEVEL_4K,
> };
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index a474f2e76d78..e9212394a530 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -5782,6 +5782,8 @@ void kvm_mmu_init_vm(struct kvm *kvm)
> node->track_write = kvm_mmu_pte_write;
> node->track_flush_slot = kvm_mmu_invalidate_zap_pages_in_memslot;
> kvm_page_track_register_notifier(kvm, node);
> +
> + kvm->arch.tdp_max_page_level = KVM_MAX_HUGEPAGE_LEVEL;
> }
>
> void kvm_mmu_uninit_vm(struct kvm *kvm)
